United Kingdom
Impact of Local Emergency Demand Response Programs on the Operation of Electricity and Gas Systems
Mar 2022
Publication
With increasing attention to climate change the penetration level of renewable energy sources (RES) in the electricity network is increasing. Due to the intermittency of RES gas‐fired power plants could play a significant role in backing up the RES in order to maintain the supply– demand balance. As a result the interaction between gas and power networks are significantly in‐ creasing. On the other hand due to the increase in peak demand (e.g. electrification of heat) net‐ work operators are willing to execute demand response programs (DRPs) to improve congestion management and reduce costs. In this context modeling and optimal implementation of DRPs in proportion to the demand is one of the main issues for gas and power network operators. In this paper an emergency demand response program (EDRP) is implemented locally to reduce the con‐ gestion of transmission lines and gas pipelines more efficiently. Additionally the effects of optimal implementation of local emergency demand response program (LEDRP) in gas and power networks using linear and non‐linear economic models (power exponential and logarithmic) for EDRP in terms of cost and line congestion and risk of unserved demand are investigated. The most reliable demand response model is the approach that has the least difference between the estimated demand and the actual demand. Furthermore the role of the LEDRP in the case of hydrogen injection instead of natural gas in the gas infrastructure is investigated. The optimal incentives for each bus or node are determined based on the power transfer distribution factor gas transfer distribution factor available electricity or gas transmission capability and combination of unit commitment with the LEDRP in the integrated operation of these networks. According to the results implementing the LEDRP in gas and power networks reduces the total operation cost up to 11% and could facilitate hydrogen injection to the network. The proposed hybrid model is implemented on a 24‐bus IEEE electricity network and a 15‐bus gas network to quantify the role and value of different LEDRP models.
Study on Applicability of Energy-Saving Devices to Hydrogen Fuel Cell-Powered Ships
Mar 2022
Publication
The decarbonisation of waterborne transport is arguably the biggest challenge faced by the maritime industry presently. By 2050 the International Maritime Organization (IMO) aims to reduce greenhouse gas emissions from the shipping industry by 50% compared to 2008 with a vision to phase out fossil fuels by the end of the century as a matter of urgency. To meet such targets action must be taken immediately to address the barriers to adopt the various clean shipping options currently at different technological maturity levels. Green hydrogen as an alternative fuel presents an attractive solution to meet future targets from international bodies and is seen as a viable contributor within a future clean shipping vision. The cost of hydrogen fuel—in the shortterm at least—is higher compared to conventional fuel; therefore energy-saving devices (ESDs) for ships are more important than ever as implementation of rules and regulations restrict the use of fossil fuels while promoting zero-emission technology. However existing and emerging ESDs in standalone/combination for traditional fossil fuel driven vessels have not been researched to assess their compatibility for hydrogen-powered ships which present new challenges and considerations within their design and operation. Therefore this review aims to bridge that gap by firstly identifying the new challenges that a hydrogen-powered propulsion system brings forth and then reviewing the quantitative energy saving capability and qualitive additional benefits of individual existing and emerging ESDs in standalone and combination with recommendations for the most applicable ESD combinations with hydrogen-powered waterborne transport presented to maximise energy saving and minimise the negative impact on the propulsion system components. In summary the most compatible combination ESDs for hydrogen will depend largely on factors such as vessel types routes propulsion operation etc. However the mitigation of load fluctuations commonly encountered during a vessels operation was viewed to be a primary area of interest as it can have a negative impact on hydrogen propulsion system components such as the fuel cell; therefore the ESD combination that can maximise energy savings as well as minimise the fluctuating loads experienced would be viewed as the most compatible with hydrogen-powered waterborne transport.
Gas Goes Green: A System for All Seasons
Oct 2021
Publication
‘A System For All Seasons’ analyses Britain’s electricity generation and consumption trends concluding that the country’s wind and solar farms will have enough spare electricity generated in spring and summer when demand is lower to produce green hydrogen to the equivalent capacity of 25 Hinkley Point C nuclear power plants.
The hydrogen stored would provide the same amount of energy needed for every person in the UK to charge a Tesla Model S electric vehicle more than 21 times in the autumn and winter months when energy demand is highest creating a clean energy buffer that avoids having to manage limited energy supplies on the international markets.
Crucially the research finds that the UK has enough capacity to store the hydrogen in a combination of salt caverns and disused oil and gas fields in the North Sea as well other locations to meet this demand.
The research also finds that using renewable hydrogen will help reduce the total number of wind farms needed in 2050 by more than 75% because it will ensure electricity generated by Britain’s wind farms is used as efficiently as possible by avoiding surplus electricity going to waste.
‘A System For All Seasons’ finds that:
The hydrogen stored would provide the same amount of energy needed for every person in the UK to charge a Tesla Model S electric vehicle more than 21 times in the autumn and winter months when energy demand is highest creating a clean energy buffer that avoids having to manage limited energy supplies on the international markets.
Crucially the research finds that the UK has enough capacity to store the hydrogen in a combination of salt caverns and disused oil and gas fields in the North Sea as well other locations to meet this demand.
The research also finds that using renewable hydrogen will help reduce the total number of wind farms needed in 2050 by more than 75% because it will ensure electricity generated by Britain’s wind farms is used as efficiently as possible by avoiding surplus electricity going to waste.
‘A System For All Seasons’ finds that:
- Britain’s wind and solar farms could generate between 60-80GW of renewable hydrogen - the equivalent capacity of 25 Hinkley Point C nuclear power plants - from spare renewable electricity generated in the spring and summer months between May and October each year.
- Running the energy system this way will reduce the need for the total electricity generating capacity of UK wind farms from 500-600GW by 2050 down to 140-190GW – a reduction of up to 76%.
- It would mean Great Britain would be using spare renewable electricity that would otherwise go to waste to produce green hydrogen. Under the alternative scenario additional wind farms would need to be built to accommodate for autumn and wind energy demand peaks but be left unused during other times of the year.
- With 140-190GW of wind generation capacity 115 to 140TWh of green hydrogen would be stored – enough energy for every person in the UK to charge a Tesla Model S more than 21 times.
- The potential storage volume from Britain’s salt fields ranges from >1TWh up to 30TWh. For disused oil and gas fields the potential storage volume for individual sites ranges from ~1TWh up to 330TWh.
The Role of Hydrogen in Powering Industry: APPG on Hydrogen report
Jul 2021
Publication
The APPG on Hydrogen has published its report urging the Government to deliver beyond its existing net zero commitments and set ambitious hydrogen targets in forthcoming strategies to reach net zero by 2050.
The All-Party Parliamentary Group (APPG) on Hydrogen’s report on the role of ‘Hydrogen in powering industry’ sets out 10 recommendations to support and accelerate the growth of the UK’s hydrogen sector and enable a sustainable energy transition.
The All-Party Parliamentary Group (APPG) on Hydrogen’s report on the role of ‘Hydrogen in powering industry’ sets out 10 recommendations to support and accelerate the growth of the UK’s hydrogen sector and enable a sustainable energy transition.
- The Government must continue to expand beyond its existing commitments of 5GW production in the forthcoming Hydrogen Strategy.
- Any forthcoming Government and devolved policies must be complementary of the wider UK low-carbon commitments.
- Industrial clusters should be prioritised for hydrogen use and will be the key catalyst for driving forward the UK’s decarbonisation of industry.
- The Government must commit to incentivising hydrogen production within the UK as opposed to importing this.
- The Government must align hydrogen production pathways with nuclear technology to enhance hydrogen production.
- The Government must develop a UK wide hydrogen network to support the transport sector including a larger-scale implementation of hydrogen refuelling stations.
- Regulators must act quickly to update energy regulations and guidance to support hydrogen’s role in powering industry.
- For hydrogen to expand in the UK a technology neutral approach is required for all types of energy systems.
- Significant and long-term financial support is required for the development deployment and operation of hydrogen technologies.
- Ofgem must ensure the hydrogen market is subject to effective competition to drive down prices for consumers.
The Dawn of Hydrogen - Fuel of the Future
Aug 2021
Publication
This is a time of enormous change for the gas industry as the UK and the world at large attempts to meet the challenges of decarbonisation in the face of climate change. Hydrogen is expected to play a vital role in achieving the government’s commitment of eliminating the UK’s contribution to climate change by 2050 with the industry creating up to 8000 jobs by 2030 and potentially unlocking up to 100000 jobs by the middle of the century. But despite the UK government’s huge ambitions hydrogen is just one piece of the puzzle and it will be necessary to seek solutions that bring the whole energy system together – including not just heat for buildings but hard-to decarbonise areas such as manufacturing road transport aviation and shipping. Here we bring you just a taste of some of the amazing work taking place across the energy sector to understand this fuel more clearly to comprehend its strengths and limitations and to integrate it into our current energy infrastructure. We hope you enjoy this special publication.
Energy and Utility Skills - Hydrogen Competency Framework Report
Jul 2021
Publication
In 2020 the Department for Business Enterprise and Industrial Strategy (BEIS) commissioned Energy & Utility Skills to develop and deliver a Hydrogen Competency Framework as part of the Hy4Heat programme. The successful completion of this work is detailed in a new report published today.
The work done by Energy & Utility Skills was underpinned by three key pillars:
Collaboration
The resulting outputs of the design development stages are:
More details about this report can be found on the Energy & Utility Skills website.
The work done by Energy & Utility Skills was underpinned by three key pillars:
Collaboration
- Driving growth in engagement levels across the industry
- Designing the framework for both initial trials and any future rollout
- The framework ensures engineers will have all the skills knowledge and understanding they need
The resulting outputs of the design development stages are:
- A Comparative Analysis of Hydrogen and existing hydrocarbon gases
- A Skills Matrix that translates the analysis into skills knowledge and understanding
- An Interim Hydrogen Technical Standard that defines acceptable parameters and requirements for hydrogen installation work
- A Hydrogen Training Specification that will enable training course consistency and facilitate industry recognition
- An independent Hydrogen Assessment Module that will facilitate the addition of a hydrogen competence category on the Gas Safe Register
More details about this report can be found on the Energy & Utility Skills website.
Heat in Buildings Strategy: Achieving Net Zero Emissions in Scotland's Buildings
Oct 2021
Publication
Sets out our vision for the future of heat in buildings and the actions we are taking in the buildings sector to deliver our climate change commitments maximise economic opportunities and ensure a just transition including helping address fuel poverty.
Towards a 100% Hydrogen Domestic Gas Network: Regulatory and Commercial Barriers to the First Demonstrator Project in the United Kingdom
May 2022
Publication
In the debate on the decarbonisation of heat renewable electricity tends to play a much more dominant role than green gases despite the potential advantages of gas in terms of utilising existing transportation networks and end-use appliances. Informed comparisons are hampered by information asymmetry; the renewable electricity has seen a huge grid level deployment whereas low-carbon hydrogen or bio-methane have been limited to some small stand-alone trials. This paper explores the regulatory and commercial challenges of implementing the first UK neighbourhood level 100% low-carbon hydrogen demonstration project. We draw on existing literature and action research to identify the key practical barriers currently hindering the ability of strategically important actors to accelerate the substitution of natural gas with low carbon hydrogen in local gas networks. This paper adds much needed contextual depth to existing generic and theoretical understandings of low-carbon hydrogen for heat transition feasibility. The learnings from pilot projects about the exclusion of hydrogen calorific value from the Local Distribution Zone calorific value calculation Special Purpose Vehicle companies holding of liability and future costs to consumers need to be quickly transferred into resilient operational practice or gas repurposing projects will continue to be less desirable than electrification using existing regulations and with more rapid delivery
Developing Networks for the Future: Long-Term Development Plan 2019
Oct 2019
Publication
This report provides you with the information you need if you have plans to interact with or connect to our gas networks. Our vision is to set the standards that all of our customers love and others aspire to. This means that our long-term plans are shaped by our customers and stakeholders. This annual publication is an important opportunity to share our latest long-term plan and our strategic thinking and seek feedback so we can continue to adapt our activities going forward. We want to make it as easy and efficient as possible for you to interact with us.
Cadent Long Term Development Plan 2019
Cadent Long Term Development Plan 2019
Analysis of Control-System Strategy and Design of a Small Modular Reactor with Different Working Fluids for Electricity and Hydrogen Production as Part of a Decentralised Mini Grid
Mar 2022
Publication
Hydrogen is increasingly being viewed as a significant fuel for future industrial processes as it offers pathways to zero emission. The UK sees hydrogen as one of a handful of low-carbon solutions for transition to net zero. Currently most hydrogen production is from steam reforming of natural gas or coal gasification both of which involve the release of carbon dioxide. Hydrogen production from mini decentralised grids via a thermochemical process coupled with electricity production could offer favourable economics for small modular reactors (SMRs) whereby demand or grid management as a solution would include redirecting the power for hydrogen production when electricity demand is low. It also offers a clean-energy alternative to the aforementioned means. SMRs could offer favourable economics due to their flexible power system as part of the dual-output function. This study objective is to investigate the critical performance parameters associated with the nuclear power plant (NPP) the cycle working fluids and control-system design for switching between electricity and hydrogen demand to support delivery as part of a mini grid system for a reactor power delivering up to approximately 600 MWth power. The novelty of the work is in the holistic parametric analysis undertaken using a novel in-house tool which analyses the NPP using different working fluids with a control function bolt-on at the offtake for hydrogen production. The results indicate that the flow conditions at the offtake can be maintained. The choice of working fluids affects the pressure component. However the recuperator and heat-exchanger effectiveness are considered as efficiency-limiting factors for hydrogen production and electricity generation. As such the benefit of high-technology heat exchangers cannot be underestimated. This is also true when deciding on the thermochemical process to bolt onto the plant. The temperature of the gas at the end of the pipeline should also be considered to ensure that the minimum temperature-requirement status for hydrogen production is me
Reducing the Cost of Low-carbon Hydrogen Production via Emerging Chemical Looping Process
Jan 2023
Publication
A thorough techno-economic analysis where inherent carbon capture is examined against state-of-the-art blue hydrogen production configurations for large (100000 Nm3 /h) and very large (333000 Nm3 /h) capacities. Advanced solvent-based technologies based on post-combustion capture and auto-thermal reformer combined with a gas heated reformer are simulated with process flowsheet software and compared with the emerging chemical looping process. A network of dynamically operated packed bed reactors has been designed and modelled using an in-house code and key parameters generating uncertainties in the results have been examined in a sensitivity analysis. The chemical looping reforming process presents a higher net reforming efficiency than the benchmark cases (8.2 % higher at large scale and 1.5 % higher at very large scale) ranged 75.4–75.7 % while the specific energy for CO2 avoidance is negative in the range of − 0.78 to − 0.85 MJ/kgCO2. In the carbon capture cases the chemical looping reforming in packed beds technology generated a levelised cost of hydrogen of 168.9 £/kNm3 H2 for the large scale and 159.1 £/kNm3 H2 for the very large scale with the values for the benchmark cases being higher at 196.4 and 166.6 £/kNm3 H2 respectively while the levelised cost of hydrogen values are 1 % higher in the benchmark cases where carbon emission price is accounted for. The carbon capture ratio is 99.9 % for the chemical looping reforming cases compared to 90–91 % for the benchmark ones thus providing a significant foreground for the scale-up and implementation of chemical looping reforming technologies for hydrogen production.
Effect of Bipolar Plate Material on Proton Exchange Membrane Fuel Cell Performance
Mar 2022
Publication
Commercialization of proton exchange membrane fuel cells can only materials provided its performance is closely related to existing technologies useful in commercial application. Other critical parameters like the utilization of cheaper materials should be taken into account during the manufacturing of the cell. A key component in the cell that has direct correlation to the cell perfor‐ mance is the flow plate. The weight coupled with cost of the cell revolves around the flow plate used in the manufacturing of the cell. This study explores materials ideal for the manufacturing of fuel cells in order to improve the overall cell performance. The investigation highlights the critical impact of varying materials used in the manufacturing of flow plates for PEM fuel cells. Stainless steel (SS) aluminium (Al) and copper (Cu) were the materials considered. The flow plate designs considered were serpentine and open pore cellular foam channel. Machine learning using python for the validation of the results with Linear regression Ridge regression and Polynomial regression algorithm was carried out. The performance of both flow field channels was compared using dif‐ ferent bipolar plate materials. The results show that metal foam flow channels overall performance was better than serpentine flow channels with all the various bipolar plate material used and Al material outperformed Cu and SS material. There is a direct correlation in terms of the outcome of the study and literature based on the data generated experimentally. It can however be concluded that molecules of hydrogen are stable on aluminium plates compared to copper and stainless steel
Modelling of Boil‐Off and Sloshing Relevant to Future Liquid Hydrogen Carriers
Mar 2022
Publication
This study presents an approach for estimating fuel boil‐off behaviour in cryogenic energy carrier ships such as future liquid hydrogen (LH2) carriers. By relying on thermodynamic model‐ ling and empirical formulas for ship motion and propulsion the approach can be used to investigate boil‐off as a function of tank properties weather conditions and operating velocities during a laden voyage. The model is first calibrated against data from a liquefied natural gas (LNG) carrier and is consequently used to investigate various design configurations of an LH2 ship. Results indicate that an LH2 ship with the same tank volume and glass wool insulation thickness as a conventional LNG carrier stores 40% of the fuel energy and is characterised by a boil‐off rate nine times higher and twice as sensitive to sloshing. Adding a reliquefaction unit can reduce the LH2 fuel depletion rate by at least 38.7% but can increase its variability regarding velocity and weather conditions. In calm weather LH2 boil‐off rates can only meet LNG carrier standards by utilising at least 6.6 times the insulation thickness. By adopting fuel cell propulsion in an LH2 ship a 1.1% increase in fuel delivery is expected. An LH2 ship with fuel cells and reliquefaction is required to be at least 1.7 times larger than an existing LNG carrierto deliverthe same energy. Further comparison of alternative scenarios indicates that LH2 carriers necessitate significant redesigns if LNG carrier standards are desired. The present approach can assist future feasibility studies featuring other vessels and propulsion technologies and can be seen as an extendable framework that can predict boil‐off in real‐time.
Future Electricity Series Part 2 - Power from Renewables
Sep 2013
Publication
The independent cross-party report highlights a ‘sensible middle ground’ in the renewables debate and calls for more effort in building cross-party consensus. It finds that the UK has only just begun to harness low carbon renewable resources bigger than North Sea oil and gas and argues that the Government could do more to narrow the scope of debate about the technology mix beyond 2020. It argues that it should work with industry and academia first to establish ‘low regrets’ levels of technology deployment and second to ensure that policies are in place to incentivise investments such as supply chain investment needed to deliver these low regrets actions.
This approach would help provide the longer term clarity that could secure supply chain investments giving the UK a head-start in the global race. The report finds that these investments could be missed delayed or more expensive if there is insufficient confidence about long term demand for key technologies such as offshore wind. Work by Government to help incentivise these investments would increase the likelihood that technology cost reductions are achieved and help mitigate against high costs if new nuclear or carbon capture and storage development fail or are delayed.
On affordability the report finds that there are ‘hidden’ benefits that the UK could see from investing more in renewables through electricity bills between now and 2020. These include: avoiding bill increases driven by fossil fuels; making electricity bills more predictable; and providing an economic boost. The extra money paid to support renewables and other low carbon generation such as nuclear power could be more than offset by energy efficiency savings although Government needs to do more to show how these savings will arise.
On sustainability the report tackles myths about the carbon emitted in manufacturing renewable technologies or in backing up varying technologies such as wind solar wave and tidal. It finds that even when considering these factors renewables are still amongst the most low carbon options. The report also looks at the sustainability of electricity from biomass. Bioenergy overall could provide up to ten per cent of energy and reduce the cost of cutting carbon by £44 billion per year in 2050. The Government’s new biomass policies are a pragmatic response to concerns about the sustainability of biomass power which balances protecting the environment building public confidence and enabling the sector to grow.
On security of supply the inquiry argues that debate should focus on the whole electricity system and that individual technologies should be considered in the context of how they add to or reduce system risks. Considered like this renewables reduce some risks such as fuel supply risks which caused concern last winter and add to others such as system balancing risks. System balancing risks from varying renewables (wind solar wave and tidal technologies) are manageable using a number of existing and developing technologies.
The independent report chaired by former Energy Minister Charles Hendry MP and Shadow Energy Minister Baroness Worthington was compiled between May and September 2013 and was sponsored by Siemens and DONG Energy. It is part of a year-long independent and cross party inquiry into the UK power sector the Future Electricity Series sponsored by the Institution of Gas Engineers and Managers.
Link to Launch Video
This approach would help provide the longer term clarity that could secure supply chain investments giving the UK a head-start in the global race. The report finds that these investments could be missed delayed or more expensive if there is insufficient confidence about long term demand for key technologies such as offshore wind. Work by Government to help incentivise these investments would increase the likelihood that technology cost reductions are achieved and help mitigate against high costs if new nuclear or carbon capture and storage development fail or are delayed.
On affordability the report finds that there are ‘hidden’ benefits that the UK could see from investing more in renewables through electricity bills between now and 2020. These include: avoiding bill increases driven by fossil fuels; making electricity bills more predictable; and providing an economic boost. The extra money paid to support renewables and other low carbon generation such as nuclear power could be more than offset by energy efficiency savings although Government needs to do more to show how these savings will arise.
On sustainability the report tackles myths about the carbon emitted in manufacturing renewable technologies or in backing up varying technologies such as wind solar wave and tidal. It finds that even when considering these factors renewables are still amongst the most low carbon options. The report also looks at the sustainability of electricity from biomass. Bioenergy overall could provide up to ten per cent of energy and reduce the cost of cutting carbon by £44 billion per year in 2050. The Government’s new biomass policies are a pragmatic response to concerns about the sustainability of biomass power which balances protecting the environment building public confidence and enabling the sector to grow.
On security of supply the inquiry argues that debate should focus on the whole electricity system and that individual technologies should be considered in the context of how they add to or reduce system risks. Considered like this renewables reduce some risks such as fuel supply risks which caused concern last winter and add to others such as system balancing risks. System balancing risks from varying renewables (wind solar wave and tidal technologies) are manageable using a number of existing and developing technologies.
The independent report chaired by former Energy Minister Charles Hendry MP and Shadow Energy Minister Baroness Worthington was compiled between May and September 2013 and was sponsored by Siemens and DONG Energy. It is part of a year-long independent and cross party inquiry into the UK power sector the Future Electricity Series sponsored by the Institution of Gas Engineers and Managers.
Link to Launch Video
Strategies for the Sampling of Hydrogen at Refuelling Stations for Purity Assessment
Aug 2021
Publication
Hydrogen delivered at hydrogen refuelling station must be compliant with requirements stated in different standards which require specialized sampling device and personnel to operate it. Currently different strategies are implemented in different parts of the world and these strategies have already been used to perform 100s of hydrogen fuel sampling in USA EU and Japan. However these strategies have never been compared on a large systematic study. The purpose of this paper is to describe and compare the different strategies for sampling hydrogen at the nozzle and summarize the key aspects of all the existing hydrogen fuel sampling including discussion on material compatibility with the impurities that must be assessed. This review highlights the fact it is currently difficult to evaluate the impact or the difference these strategies would have on the hydrogen fuel quality assessment. Therefore comparative sampling studies are required to evaluate the equivalence between the different sampling strategies. This is the first step to support the standardization of hydrogen fuel sampling and to identify future research and development area for hydrogen fuel sampling.
Differentiating Gas Leaks from Normal Appliance Use
Jun 2021
Publication
DNV has carried out an investigation into potential uses for smart gas meter data as part of Phase 1 of the Modernising Energy Data Applications competition as funded by UK Research & Innovation. In particular a series of calculations have been carried out to investigate the possibility of differentiating accidental gas leaks from normal appliance use in domestic properties. This is primarily with the aim of preventing explosions but the detection of leaks also has environmental and financial benefits.
Three gases have been considered in this study:
An examination of detailed historical incident information suggests that the explosions that lead to fatalities or significant damage to houses are typically of the type that would be more likely to be detected and prevented. It is estimated that between 25% and 75% of the more severe explosions could be prevented depending on which potential improvements are implemented.
Based on the conservative estimates of explosion prevention a cost benefit analysis suggests that it is justifiable to spend between around £1 and £10 per meter installed to implement the proposed technology. This is based purely on lives saved and does not take account of other benefits.
Three gases have been considered in this study:
- A representative UK natural gas composition.
- A blend of 80% natural gas and 20% hydrogen.
- Pure hydrogen.
- Small holes of up to 1 mm rarely reach flammable gas/air concentrations for any gas except under the most unfavourable conditions such as small volumes combined with low ventilation rates. These releases would likely be detected within 6 to 12 hours.
- Medium holes between 1 mm and 6 mm give outflow rates equivalent to a moderate to high level of gas use by appliances. The ability to detect these leaks is highly dependent on the hole size the time at which the leak begins and the normal gas use profile in the building. The larger leaks in this category would be detected within 30 to 60 minutes while the smaller leaks could take several hours to be clearly differentiated from appliance use. This is quick enough to prevent some explosions.
- Large holes of over 6 mm give leak rates greater than any gas use by appliances. These releases rapidly reach a flammable gas/air mixture in most cases but would typically be detected within the first 30-minute meter output period. Again some explosions could be prevented in this timescale.
An examination of detailed historical incident information suggests that the explosions that lead to fatalities or significant damage to houses are typically of the type that would be more likely to be detected and prevented. It is estimated that between 25% and 75% of the more severe explosions could be prevented depending on which potential improvements are implemented.
Based on the conservative estimates of explosion prevention a cost benefit analysis suggests that it is justifiable to spend between around £1 and £10 per meter installed to implement the proposed technology. This is based purely on lives saved and does not take account of other benefits.
IGEM/TD/13 Edition 3 Supplement 1 - Pressure Regulating Installations for Hydrogen at Pressures Exceeding 7 Bar
Nov 2021
Publication
IGEM/TD/13 Standard applies to the safe design construction inspection testing operation and maintenance of pressure regulating installations (PRIs) in accordance with current knowledge and operational experience.
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations
You can purchase the standard here
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations
- with an upstream maximum operating pressure (MOP) not greater than 100 bar
- with an outlet pressure greater than or equal to 7 bar
- for use with Hydrogen or NG/H blends with a Hydrogen content greater than 10 %
- operating with a temperature range between -20°C and 120°C.
You can purchase the standard here
Injection of Gaseous Hydrogen into a Natural Gas Pipeline
May 2022
Publication
The injection of pure hydrogen at a T-junction into a horizontal pipe carrying natural gas is analysed computationally to understand the influence of blending and pipe geometry (diameter ratio various 90 orientations) on mixing for a target of 4.8e20% volume fraction hydrogen blend. The strongly inhomogeneous distribution of hydrogen within the pipe flow and on the pipe walls could indicate the location of potential pipe material degradation including embrittlement effects. The low molecular mass of hydrogen reduces the penetration of a side-branch flow and increases the buoyancy forces leading to stratification with high hydrogen concentrations on the upper pipe surface downstream of the branch. Top-side injection leads to the hydrogen concentration remaining >40% for up to 8 pipe diameters from the injection point for volumetric dilutions ( D) less than 30%. Under-side injection promotes mixing within the flow interior and reduces wall concentration at the lower surface compared to top-side injection. The practical implications for these results in terms of mixing requirements and the contrasting constraint of codes of practice and energy demands are discussed.
UK Hydrogen Strategy
Aug 2021
Publication
The UK’s first-ever Hydrogen Strategy drives forward the commitments laid out in the Prime Minister’s ambitious 10 Point Plan for a green industrial revolution by setting the foundation for how the UK government will work with industry to meet its ambition for 5GW of low carbon hydrogen production capacity by 2030 – the equivalent of replacing natural gas in powering around 3 million UK homes each year as well as powering transport and businesses particularly heavy industry.<br/>A booming UK-wide hydrogen economy could be worth £900 million and create over 9000 high-quality jobs by 2030 potentially rising to 100000 jobs and worth up to £13 billion by 2050. By 2030 hydrogen could play an important role in decarbonising polluting energy-intensive industries like chemicals oil refineries power and heavy transport like shipping HGV lorries and trains by helping these sectors move away from fossil fuels. Low-carbon hydrogen provides opportunities for UK companies and workers across our industrial heartlands.<br/>With government analysis suggesting that 20-35% of the UK’s energy consumption by 2050 could be hydrogen-based this new energy source could be critical to meet our targets of net zero emissions by 2050 and cutting emissions by 78% by 2035 – a view shared by the UK’s independent Climate Change Committee. In the UK a low-carbon hydrogen economy could deliver emissions savings equivalent to the carbon captured by 700 million trees by 2032 and is a key pillar of capitalising on cleaner energy sources as the UK moves away from fossil fuels.
Electrification Versus Hydrogen for UK Road Freight: Conclusions from a Systems Analysis of Transport Energy Transitions
Mar 2022
Publication
Collectively the UK investment in transport decarbonisation is greater than £27B from government for incentivising zero-emission vehicles as part of an urgent response to decarbonise the transport sector. The investments made must facilitate a transition to a long-term solution. The success relies on coordinating and testing the evolution of both the energy and transport systems this avoids the risk of unforeseen consequences in both systems and therefore de-risks investment Here we present a semiquantitative energy and transport system analysis for UK road freight focusing on two primary investment areas for nation-wide decarbonisation namely electrification and hydrogen propulsion. Our study assembles and assesses the potential roadblocks of these energy systems into a concise record and considers the infrastructure in relation to all other components within the energy system. It highlights that for system-wide success and resilience a hydrogen system must overcome hydrogen production and distribution barriers whereas an electric system needs to optimise storage solutions and charging facilities. Without cohesive co-evolving energy networks the planning and operational modelling of transport decarbonisation may fall short of meaningful real-world results. A developed understanding of the dependencies between the energy and transport systems is a necessary step in the development of meaningful operational transport models that could de-risk investment in both the energy and transport systems.
HydroGenerally - Episode 3: Lift Off for Hydrogen in Aviation
Apr 2022
Publication
In this third episode Steffan Eldred and Hannah Abson from Innovate UK KTN are exploring the scale of the opportunity that hydrogen and aviation present alongside their special guest Katy Milne Head of Industrial Strategy at FlyZero.
The podcast can be found on their website
The podcast can be found on their website
A Combined Heat and Green Hydrogen (CHH) Generator Integrated with a Heat Network
Sep 2021
Publication
Combined heat and power (CHP) systems offer high energy efficiencies as they utilise both the electricity generated and any excess heat by co-suppling to local consumers. This work presents the potential of a combined heat and hydrogen (CHH) system a solution where Proton exchange membrane (PEM) electrolysis systems producing hydrogen at 60–70% efficiency also co-supply the excess heat to local heat networks. This work investigates the method of capture and utilisation of the excess heat from electrolysis. The analysed system was able to capture 312 kW of thermal energy per MW of electricity and can deliver it as heated water at either 75 ◦C or 45 ◦C this appropriate for existing district heat networks and lower temperature heat networks respectively. This yields an overall CHH system efficiency of 94.6%. An economic analysis was conducted based on income generated through revenue sales of both hydrogen and heat which resulted in a significant reduction in the Levelized Cost of Hydrogen.
Hydrogen Production, Distribution, Storage and Power Conversion in a Hydrogen Economy - A Technology Review
Aug 2021
Publication
To meet ambitious targets for greenhouse gas emissions reduction in the 2035-2050 timeframe hydrogen has been identified as a clean “green” fuel of interest. In comparison to fossil fuel use the burning of hydrogen results in zero CO2 emissions and it can be obtained from renewable energy sources. In addition to zero CO2 emissions hydrogen has several other attractive properties such as higher gravimetric energy content and wider flammability limits than most fossil fuels. However there are practical limitations to its widespread use at present which include low volumetric energy density in the gaseous state and high well-to-wheel costs when compared to fossil fuel production and distribution. In this paper a review is undertaken to identify the current state of development of key areas of the hydrogen network such as production distribution storage and power conversion technology. At present high technology costs still are a barrier to widespread hydrogen adoption but it is envisioned that as scale of production increases then costs are likely to fall. Technical barriers to a hydrogen economy adoption are not as significant as one might think as key technologies in the hydrogen network are already mature with working prototypes already developed for technologies such as liquid hydrogen composite cryotanks and proton exchange membrane fuel cells. It is envisioned that with continuous investment to achieve requisite scale that a hydrogen economy could be realised sooner rather than later with novel concepts such as turboelectric distributed propulsion enabled by a shift to hydrogen-powered network.
The Effect of Symmetrically Tilt Grain Boundary of Aluminum on Hydrogen Diffusion
Feb 2022
Publication
High-strength aluminum alloys are widely used in industry. Hydrogen embrittlement greatly reduces the performance and service safety of aluminum alloys. The hydrogen traps in aluminum profoundly affect the hydrogen embrittlement of aluminum. Here we took a coincidence-site lattice (CSL) symmetrically tilted grain boundary (STGB) Σ5(120)[001] as an example to carry out molecular dynamics (MD) simulations of hydrogen diffusion in aluminum at different temperatures and to obtain results and rules consistent with the experiment. At 700 K three groups of MD simulations with concentrations of 0.5 2.5 and 5 atomic % hydrogen (at. % H) were carried out for STGB models at different angles. By analyzing the simulation results and the MSD curves of hydrogen atoms we found that in the low hydrogen concentration of STGB models the grain boundaries captured hydrogen atoms and hindered their movement. In high-hydrogen-concentration models the diffusion rate of hydrogen atoms was not affected by the grain boundaries. The analysis of the simulation results showed that the diffusion of hydro-gen atoms at the grain boundary is anisotropic.
Crack Management of Hydrogen Pipelines
Sep 2021
Publication
The climate emergency is one of the biggest challenges humanity must face in the 21st century. The global energy transition faces many challenges when it comes to ensuring a sustainable reliable and affordable energy supply. A likely outcome is decarbonizing the existing gas infrastructure. This will inevitably lead to greater penetration of hydrogen. While the introduction of hydrogen into natural gas transmission and distribution networks creates challenges there is nothing new or inherently impossible about the concept. Indeed more than 4000 kilometers of hydrogen pipelines are currently in operation. These pipelines however were (almost) all built and operated exclusively in accordance with specific hydrogen codes which tend to be much more restrictive than their natural gas equivalents. This means that the conversion of natural gas pipelines which have often been in service for decades and have accumulated damage and been subject to cracking threats (e.g. fatigue or stress corrosion cracking (SCC)) throughout their lifetime can be challenging. This paper will investigate the impact of transporting hydrogen on the crack management of existing natural gas pipelines from an overall integrity perspective. Different cracking threats will be described including recent industry experience of those which are generic to all steel pipelines but exacerbated by hydrogen and those which are hydrogen specific. The application of a Hydrogen Framework to identify characterise and manage credible cracking threats to pipelines in order to help enable the safe economic and successful introduction of hydrogen into the natural gas network will be discussed.
Our Green Print: Future Heat for Everyone
Jul 2021
Publication
Green Print - Future Heat for Everyone draws together technical consumer and economic considerations to create a pioneering plan to transition 22 million UK homes to low carbon heat by 2050.<br/>Our Green Print underlines the scale of the challenge ahead acknowledging that a mosaic of low carbon heating solutions will be required to meet the needs of individual communities and setting out 12 key steps that can be taken now in order to get us there<br/>The Climate Change Committee (CCC) estimates an investment spend of £250bn to upgrade insulation and heating in homes as well as provide the infrastructure to deliver the energy.<br/>This is a task of unprecedented scale the equivalent of retro-fitting 67000 homes every month from now until 2050. In this Report Cadent takes the industry lead in addressing the challenge.
An Evaluation of Turbocharging and Supercharging Options for High-Efficiency Fuel Cell Electric Vehicles
Dec 2018
Publication
Mass-produced off-the-shelf automotive air compressors cannot be directly used for boosting a fuel cell vehicle (FCV) application in the same way that they are used in internal combustion engines since the requirements are different. These include a high pressure ratio a low mass flow rate a high efficiency requirement and a compact size. From the established fuel cell types the most promising for application in passenger cars or light commercial vehicle applications is the proton exchange membrane fuel cell (PEMFC) operating at around 80 ◦C. In this case an electric-assisted turbocharger (E-turbocharger) and electric supercharger (single or two-stage) are more suitable than screw and scroll compressors. In order to determine which type of these boosting options is the most suitable for FCV application and assess their individual merits a co-simulation of FCV powertrains between GT-SUITE and MATLAB/SIMULINK is realised to compare vehicle performance on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle. The results showed that the vehicle equipped with an E-turbocharger had higher performance than the vehicle equipped with a two-stage compressor in the aspects of electric system efficiency (+1.6%) and driving range (+3.7%); however for the same maximal output power the vehicle’s stack was 12.5% heavier and larger. Then due to the existence of the turbine the E-turbocharger led to higher performance than the single-stage compressor for the same stack size. The solid oxide fuel cell is also promising for transportation application especially for a use as range extender. The results show that a 24-kWh electric vehicle can increase its driving range by 252% due to a 5 kW solid oxide fuel cell (SOFC) stack and a gas turbine recovery system. The WLTP driving range depends on the charge cycle but with a pure hydrogen tank of 6.2 kg the vehicle can reach more than 600 km.
Fugitive Hydrogen Emissions in a Future Hydrogen Economy
Apr 2022
Publication
There is an increasing body of evidence that leakage of hydrogen to the atmosphere will have an indirect warming effect on the climate and so should be minimised.<br/>This study investigates and quantifies the current understanding of potential hydrogen emissions in the different sectors across a future hydrogen value-chain. It shows that there are some key areas in production distribution and end-use where there could potentially be significant leaks of hydrogen to the atmosphere. In some of these areas there are clear mitigation options while with others the options are less clear due to uncertainty in either data or future technology development.<br/>The report recommends further research and development to reduce the main leak pathways and additional evidence gathering in key areas where there is currently inadequate data to make accurate predictions.<br/>The study was commissioned by BEIS and conducted by the Frazer-Nash consultancy.
The Evolution and Structure of Ignited High-pressure Cryogenic Hydrogen Jets
Jun 2022
Publication
The anticipated upscaling of hydrogen energy applications will involve the storage and transport of hydrogen at cryogenic conditions. Understanding the potential hazard arising from leaks in high-pressure cryogenic storage is needed to improve hydrogen safety. The manuscript reports a series of numerical simulations with detailed chemistry for the transient evolution of ignited high-pressure cryogenic hydrogen jets. The study aims to gain insight of the ignition processes flame structures and dynamics associated with the transient flame evolution. Numerical simulations were firstly conducted for an unignited jet released under the same cryogenic temperature of 80 K and pressure of 200 bar as the considered ignited jets. The predicted hydrogen concentrations were found to be in good agreement with the experimental measurements. The results informed the subsequent simulations of the ignited jets involving four different ignition locations. The predicted time series snapshots of temperature hydrogen mass fraction and the flame index are analyzed to study the transient evolution and structure of the flame. The results show that a diffusion combustion layer is developed along the outer boundary of the jet and a side diffusion flame is formed for the near-field ignition. For the far-field ignition an envelope flame is observed. The flame structure contains a diffusion flame on the outer edge and a premixed flame inside the jet. Due to the complex interactions between turbulence fuel-air mixing at cryogenic temperature and chemical reactions localized spontaneous ignition and transient flame extinguishment are observed. The predictions also captured the experimentally observed deflagration waves in the far-field ignited jets.
A Review of Factors Affecting SCC Initiation and Propagation in Pipeline Carbon Steels
Aug 2022
Publication
Pipelines have been installed and operated around the globe to transport oil and gas for decades. They are considered to be an effective economic and safe means of transportation. The major concern in their operation is corrosion. Among the different forms of corrosion stress corrosion cracking (SCC) which is caused by stresses induced by internal fluid flow or other external forces during the pipeline’s operation in combined action with the presence of a corrosive medium can lead to pipeline failure. In this paper an extensive review of different factors affecting SCC of pipeline steels in various environmental conditions is carried out to understand their impact. Several factors such as temperature presence of oxidizers (O2 CO2 H2S etc.) composition and concentration of medium pH applied stress and microstructure of the metal/alloy have been established to affect the SCC of pipeline steels. SCC susceptibility of a steel at a particular temperature strongly depends on the type and composition of the corrosive medium and microstructure. It was observed that pipeline steels with water quenched and quenched and tempered heat treatments such as those that consist of acicular ferrite or bainitic ferrite grains are more susceptible to SCC irrespective of solution type and composition. Applied stress stress concentration and fluctuating stress facilitates SCC initiation and propagation. In general the mechanisms for crack initiation and propagation in near-neutral solutions are anodic dissolution and hydrogen embrittlement.
Ammonia as Hydrogen Carrier for Transportation; Investigation of the Ammonia Exhaust Gas Fuel Reforming
Jun 2013
Publication
In this paper we show for the first time the feasibility of ammonia exhaust gas reforming as a strategy for hydrogen production used in transportation. The application of the reforming process and the impact of the product on diesel combustion and emissions were evaluated. The research was started with an initial study of ammonia autothermal reforming (NH3 e ATR) that combined selective oxidation of ammonia (into nitrogen and water) and ammonia thermal decomposition over a ruthenium catalyst using air as the oxygen source. The air was later replaced by real diesel engine exhaust gas to provide the oxygen needed for the exothermic reactions to raise the temperature and promote the NH3 decomposition. The main parameters varied in the reforming experiments are O2/NH3 ratios NH3 concentration in feed gas and gas e hourly e space e velocity (GHSV). The O2/NH3 ratio and NH3 concentration were the key factors that dominated both the hydrogen production and the reforming process efficiencies: by applying an O2/NH3 ratio ranged from 0.04 to 0.175 2.5e3.2 l/min of gaseous H2 production was achieved using a fixed NH3 feed flow of 3 l/min. The reforming reactor products at different concentrations (H2 and unconverted NH3) were then added into a diesel engine intake. The addition of considerably small amount of carbon e free reformate i.e. represented by 5% of primary diesel replacement reduced quite effectively the engine carbon emissions including CO2 CO and total hydrocarbons.
Moving Toward the Low-carbon Hydrogen Economy: Experiences and Key Learnings from National Case Studies
Sep 2022
Publication
The urgency to achieve net-zero carbon dioxide (CO2) emissions by 2050 as first presented by the IPCC special report on 1.5°C Global Warming has spurred renewed interest in hydrogen to complement electrification for widespread decarbonization of the economy. We present reflections on estimates of future hydrogen demand optimization of infrastructure for hydrogen production transport and storage development of viable business cases and environmental impact evaluations using life cycle assessments. We highlight challenges and opportunities that are common across studies of the business cases for hydrogen in Germany the UK the Netherlands Switzerland and Norway. The use of hydrogen in the industrial sector is an important driver and could incentivise large-scale hydrogen value chains. In the long-term hydrogen becomes important also for the transport sector. Hydrogen production from natural gas with capture and permanent storage of the produced CO2 (CCS) enables large-scale hydrogen production in the intermediate future and is complementary to hydrogen from renewable power. Furthermore timely establishment of hydrogen and CO2 infrastructures serves as an anchor to support the deployment of carbon dioxide removal technologies such as direct air carbon capture and storage (DACCS) and biohydrogen production with CCS. Significant public support is needed to ensure coordinated planning governance and the establishment of supportive regulatory frameworks which foster the growth of hydrogen markets.
Regional Uptake of Direct Reduction Iron Production Using Hydrogen Under Climate Policy
Nov 2022
Publication
The need to reduce CO2 emissions to zero by 2050 has meant an increasing focus on high emitting industrial sectors such as steel. However significant uncertainties remain as to the rate of technology diffusion across steel production pathways in different regions and how this might impact on climate ambition. Informed by empirical analysis of historical transitions this paper presents modelling on the regional deployment of Direction Reduction Iron using hydrogen (DRI-H2). We find that DRI-H2 can play a leading role in the decarbonisation of the sector leading to near-zero emissions by 2070. Regional spillovers from early to late adopting regions can speed up the rate of deployment of DRI-H2 leading to lower cumulative emissions and system costs. Without such effects cumulative emissions are 13% higher than if spillovers are assumed and approximately 15% and 20% higher in China and India respectively. Given the estimates of DRI-H2 cost-effectiveness relative to other primary production technologies we also find that costs increase in the absence of regional spillovers. However other factors can also have impacts on deployment emission reductions and costs including the composition of the early adopter group material efficiency improvements and scrap recycling rates. For the sector to achieve decarbonisation key regions will need to continue to invest in low carbon steel projects recognising their broader global benefit and look to develop and strengthen policy coordination on technologies such as DRI-H2.
Progress in Reducing Emissions in Scotland: 2021 Report to Parliament
Dec 2021
Publication
This is the tenth annual Progress Report to the Scottish Parliament as required by the Climate Change (Scotland) Act 2009. This year’s report shows that in 2019 Scotland’s greenhouse emissions fell by 2% compared to 2018 and are now 44% below 1990 levels. The reductions were largely driven by the manufacturing and construction and fuel supply sectors with electricity generation remaining the biggest driver of emissions cuts over the past decade (2009-2019). The potential for further emissions savings from electricity generation has however largely run out.
The focus must now shift to ensuring that rapid emissions reductions are delivered with no further delay to allow Scotland to meet its legislated 2030 target.
This report and other reports by the Climate Change Committee can be downloaded on their website.
The focus must now shift to ensuring that rapid emissions reductions are delivered with no further delay to allow Scotland to meet its legislated 2030 target.
This report and other reports by the Climate Change Committee can be downloaded on their website.
Hydrogen-Enriched Compressed Natural Gas Network Simulation for Consuming Green Hydrogen Considering the Hydrogen Diffusion Process
Sep 2022
Publication
Transporting green hydrogen by existing natural gas networks has become a practical means to accommodate curtailed wind and solar power. Restricted by pipe materials and pressure levels there is an upper limit on the hydrogen blending ratio of hydrogen-enriched compressed natural gas (HCNG) that can be transported by natural gas pipelines which affects whether the natural gas network can supply energy safely and reliably. To this end this paper investigates the effects of the intermittent and fluctuating green hydrogen produced by different types of renewable energy on the dynamic distribution of hydrogen concentration after it is blended into natural gas pipelines. Based on the isothermal steady-state simulation results of the natural gas network two convection–diffusion models for the dynamic simulation of hydrogen injections are proposed. Finally the dynamic changes of hydrogen concentration in the pipelines under scenarios of multiple green hydrogen types and multiple injection nodes are simulated on a seven-node natural gas network. The simulation results indicate that compared with the solar-power-dominated hydrogen productionblending scenario the hydrogen concentrations in the natural gas pipelines are more uniformly distributed in the wind-power-dominated scenario and the solar–wind power balance scenario. To be specific in the solar-power-dominated scenario the hydrogen concentration exceeds the limit for more time whilst the overall hydrogen production is low and the local hydrogen concentration in the natural gas network exceeds the limit for nearly 50% of the time in a day. By comparison in the wind-power-dominated scenario all pipelines can work under safe conditions. The hydrogen concentration overrun time in the solar–wind power balance scenario is also improved compared with the solar-power-dominated scenario and the limit-exceeding time of the hydrogen concentration in Pipe 5 and Pipe 6 is reduced to 91.24% and 91.99% of the solar-power-dominated scenario. This work can help verify the day-ahead scheduling strategy of the electricity-HCNG integrated energy system (IES) and provide a reference for the design of local hydrogen production-blending systems.
Critical Parameters Controlling Wettability in Hydrogen Underground Storage - An Analytical Study
Sep 2022
Publication
Hypothesis.<br/>The large-scale implementation of hydrogen economy requires immense storage spaces to facilitate the periodic storage/production cycles. Extensive modelling of hydrogen transport in porous media is required to comprehend the hydrogen-induced complexities prior to storage to avoid energy loss. Wettability of hydrogen-brine-rock systems influence flow properties (e.g. capillary pressure and relative permeability curves) and the residual saturations which are all essential for subsurface hydrogen systems.<br/>Model.<br/>This study aims to understand which parameters critically control the contact angle for hydrogen-brine-rock systems using the surface force analysis following the DLVO theory and sensitivity analysis. Furthermore the effect of roughness is studied using the Cassie-Baxter model.<br/>Findings.<br/>Our results reveal no considerable difference between H2 and other gases such as N2. Besides the inclusion of roughness highly affects the observed apparent contact angles and even lead to water-repelling features. It was observed that contact angle does not vary significantly with variations of surface charge and density at high salinity which is representative for reservoir conditions. Based on the analysis it is speculated that the influence of roughness on contact angle becomes significant at low water saturation (i.e. high capillary pressure).
Life Cycle Cost Analysis for Scotland Short-Sea Ferries
Feb 2023
Publication
The pathway to zero carbon emissions passing through carbon emissions reduction is mandatory in the shipping industry. Regarding the various methodologies and technologies reviewed for this purpose Life Cycle Cost Analysis (LCCA) has been used as an excellent tool to determine economic feasibility and sustainability and to present directions. However insufficient commercial applications cause a conflict of opinion on which fuel is the key to decarbonisation. Many LCCA comparison studies about eco-friendly ship propulsion claim different results. In order to overcome this and discover the key factors that affect the overall comparative analysis and results in the maritime field it is necessary to conduct the comparative analysis considering more diverse case ships case routes and various types that combine each system. This study aims to analyse which greener fuels are most economically beneficial for the shipping sector and prove the factors influencing different results in LCCA. This study was conducted on hydrogen ammonia and electric energy which are carbon-free fuels among various alternative fuels that are currently in the limelight. As the power source a PEMFC and battery were used as the main power source and a solar PV system was installed as an auxiliary power source to compare economic feasibility. Several cost data for LCCA were selected from various feasible case studies. As the difficulty caused by the storage and transportation of hydrogen and ammonia should not be underestimated in this study the LCCA considers not only the CapEx and OpEx but also fuel transport costs. As a result fuel cell propulsion systems with hydrogen as fuel proved financial effectiveness for short-distance ferries as they are more inexpensive than ammonia-fuelled PEMFCs and batteries. The fuel cost takes around half of the total life-cycle cost during the life span.
Enabling Hydrogen Blending From Industrial Clusters
Nov 2022
Publication
This study has been commissioned by the gas transporters as part of the Gas Goes Green (GGG)2 work programme to develop and report a ‘gas transporter view’ on how to facilitate hydrogen blending from industrial clusters which are likely to form the initial source for hydrogen blending in the gas network. This view has been developed through engagement carried out with industrial clusters and other stakeholders as well as drawing on learnings from a previous hydrogen blending study.3 The key takeaways of this study are that: l Enabling hydrogen blending from industrial clusters can be done in a pragmatic way with limited need for change to existing gas frameworks. l Where frameworks do need to change the changes are incremental rather than involving overhaul of existing frameworks and are highly workable. l While there remain uncertainties as to the nature of blending at each cluster (e.g. the volume and profile of hydrogen injections) in general the changes required to commercial and regulatory frameworks are the same implying that they are low regret. Below we summarise gas transporters’ preferred approach to facilitating hydrogen blending from industrial clusters including both the policy decisions needed and the changes required to commercial and regulatory frameworks. We note that this work has not involved a legal review and that one will be required as part of the process of implementing the framework changes described below.
Spontaneous Ignition of Cryo-Compressed Hydrogen in a T-Shaped Channel System
Aug 2022
Publication
Sudden releases of pressurised hydrogen may spontaneously ignite by the so-called “diffusion ignition” mechanism. Several experimental and numerical studies have been performed on spontaneous ignition for compressed hydrogen at ambient temperature. However there is no knowledge of the phenomenon for compressed hydrogen at cryogenic temperatures. The study aims to close this knowledge gap by performing numerical experiments using a computational fluid dynamics model validated previously against experiments at atmospheric temperatures to assess the effect of temperature decrease from ambient 300 K to cryogenic 80 K. The ignition dynamics is analysed for a T-shaped channel system. The cryo-compressed hydrogen is initially separated from the air in the T-shaped channel system by a burst disk (diaphragm). The inertia of the burst disk is accounted for in the simulations. The numerical experiments were carried out to determine the hydrogen storage pressure limit leading to spontaneous ignition in the configuration under investigation. It is found that the pressure limit for spontaneous ignition of the cryo-compressed hydrogen at temperature 80 K is 9.4 MPa. This is more than 3 times larger than pressure limit for spontaneous ignition of 2.9 MPa in the same setup at ambient temperature of 300 K.
Green Hydrogen Production and Use in Low- and Middle-income Countries: A Least-cost Geospatial Modelling Approach Applied to Kenya
May 2023
Publication
With the rising threat of climate change green hydrogen is increasingly seen as the high-capacity energy storage and transport medium of the future. This creates an opportunity for low- and middle-income countries to leverage their high renewable energy potential to produce use and export low-cost green hydrogen creating environmental and economic development benefits. While identifying ideal locations for green hydrogen production is critical for countries when defining their green hydrogen strategies there has been a paucity of adequate geospatial planning approaches suitable to low- and middle-income countries. It is essential for these countries to identify green hydrogen production sites which match demand to expected use cases such that their strategies are economically sustainable. This paper therefore develops a novel geospatial cost modelling method to optimize the location of green hydrogen production across different use cases with a focus on suitability to low- and middle-income countries. This method is applied in Kenya to investigate the potential hydrogen supply chain for three use cases: ammonia-based fertilizer freight transport and export. We find hydrogen production costs of e3.7–9.9/kgH2 are currently achievable across Kenya depending on the production location chosen. The cheapest production locations are identified to the south and south-east of Lake Turkana. We show that ammonia produced in Kenya can be cost-competitive given the current energy crisis and that Kenya could export hydrogen to Rotterdam with costs of e7/kgH2 undercutting current market prices regardless of the carrier medium. With expected techno-economic improvements hydrogen production costs across Kenya could drop to e1.8–3.0/kgH2 by 2030.
Heating Economics Evaluated Against Emissions: An Analysis of Low-carbon Heating Systems with Spatiotemporal and Dwelling Variations
Oct 2022
Publication
An understanding of heating technologies from the consumers’ perspective is critical to ensure low-carbon technologies are adopted for reducing their current associated emissions. Existing studies from the consumers’ perspective do not compare and optimise the full range and combinations of potential heating systems. There is also little consideration of how spatiotemporal and dwelling variations combined alter the economic and environmental effectiveness of technologies. The novelty of this paper is the creation and use of a new comprehensive framework to capture the range of heating technologies and their viability for any specific dwelling’s traits and climate from customers’ perspective which is missing from current studies. The model optimises combinations of prime heaters energy sources ancillary solar technologies and sizes thermal energy storage sizes and tariffs with hourly heating simulation across a year and compares their operation capital and lifetime costs alongside emissions to realise the true preferential heating systems for customers which could be used by various stakeholders. Using the UK as a case study the results show electrified heating is generally the optimum lifetime cost solution mainly from air source heat pumps coupled with photovoltaics. However direct electrical heating becomes more economically viable as dwelling demands reduce from smaller dwellings or warmer climates as shorter durations of the ownership are considered or with capital cost constraints from lower income households. Understanding this is of high importance as without correctly targeted incentives a larger uptake of direct electrical heating may occur which will burden the electrical network and generation to a greater extent than more efficient heat pumps.
Next for Net Zero Podcast: Unlock & Understand, Achieving a More Sustainable Future
Sep 2022
Publication
This episode examines how we are tackling a sustainable future – with Net Zero hurtling towards us at great pace. We’re around a year on from the pledges made at COP26 the UK’s Green Recovery initiative is well under way and by next year Britain is aiming to blend up to 20 per cent hydrogen into its gas networks. So now is the time to continue to unlock new insight and understand further the realities of both the challenges and opportunities ahead.
The podcast can be found here.
The podcast can be found here.
Green Ammonia as a Spatial Energy Vector: A Review
May 2021
Publication
Green hydrogen is considered a highly promising vector for deep decarbonisation of energy systems and is forecast to represent 20% of global energy use by 2050. In order to secure access to this resource Japan Germany and South Korea have announced plans to import hydrogen; other major energy consumers are sure to follow. Ammonia a promising hydrogen derivative may enable this energy transport by densifying hydrogen at relatively low cost using well-understood technologies. This review seeks to describe a global green ammonia import/export market: it identifies benefits and limitations of ammonia relative to other hydrogen carriers the costs of ammonia production and transport and the constraints on both supply and demand. We find that green ammonia as an energy vector is likely to be critical to future energy systems but that gaps remain in the literature. In particular rigorous analysis of production and transport costs are rarely paired preventing realistic assessments of the delivered cost of energy or the selection of optimum import/export partners to minimise the delivered cost of ammonia. Filling these gaps in the literature is a prerequisite to the development of robust hydrogen and ammonia strategies and to enable the formation of global import and export markets of green fuel
A Review on Ports' Readiness to Facilitate International Hydrogen Trade
Jan 2023
Publication
The existing literature on the hydrogen supply chains has knowledge gaps. Most studies focus on hydrogen production storage transport and utilisation but neglect ports which are nexuses in the supply chains. To fill the gap this paper focuses on ports' readiness for the upcoming hydrogen international trade. Potential hydrogen exporting and importing ports are screened. Ports' readiness for hydrogen export and import are reviewed from perspectives of infrastructure risk management public acceptance regulations and standards and education and training. The main findings are: (1) liquid hydrogen ammonia methanol and LOHCs are suitable forms for hydrogen international trade; (2) twenty ports are identified that could be first movers; among them twelve are exporting ports and eight are importing ports; (3) ports’ readiness for hydrogen international trade is still in its infancy and the infrastructure construction or renovation risk management measures establishment of regulations and standards education and training all require further efforts.
Technical and Economic Performance Assessment of Blue Hydrogen Production Using New Configuration Through Modelling and Simulation
Mar 2024
Publication
Steam methane reforming (SMR) is the dominant process for hydrogen production which produce large amount of carbon dioxide (CO2) as a by-product. To address concerns about carbon emissions there is an increasing focus on blue hydrogen to mitigate carbon emissions during hydrogen production. However the commercialization of blue hydrogen production (BHP) is hindered by the challenges of high cost and energy consumption. This study proposes a new configuration to address these challenges which is characterized by: (a) the use of piperazine (PZ) as a solvent which has a high CO2 absorption efficiency; (b) a more efficient heat exchange configuration which recovers the waste exergy from flue gas; (c) the advanced flash stripper (AFS) was adopted to reduce the capital cost due to its simpler stripper configuration. In addition the technical and economic performance of the proposed energy and cost-saving blue hydrogen production (ECSB) process is investigated and compared with the standard SMR process. The detailed models of the SMR process and the post-combustion carbon capture (PCC) process were developed and integrated in Aspen plus® V11. The results of the technical analysis showed that the ECSB process with 30 wt.% PZ achieves a 36.3 % reduction in energy penalty when compared to the standard process with 30 wt.% Monoethanolamine (MEA). The results of the economic analysis showed that the lowest levelized cost of blue hydrogen (LCBH) was achieved by the ECSB process with 30 wt.% PZ. Compared to the BHP process with 30 wt.% MEA the LCBH was reduced by 19.7 %.
Gas Goes Green: Britain's Hydrogen Blending Delivery Plan
Jan 2022
Publication
Britain’s Hydrogen Blending Delivery Plan which sets out how all five of Britain’s gas grid companies will meet the Government’s target for Britain’s network of gas pipes to be ready to deliver 20% hydrogen to homes and businesses from 2023 as a replacement for natural gas.
Ammonia: Zero-carbon Fertiliser, Fuel and Energy Storage
Feb 2020
Publication
This briefing considers the opportunities and challenges associated with the manufacture and future use of zero-carbon ammonia which is referred to in this report as green ammonia. The production of green ammonia has the capability to impact the transition towards zero-carbon through the decarbonisation of its current major use in fertiliser production. Perhaps as significantly it has the following potential uses: • As a medium to store and transport chemical energy with the energy being released either by directly reacting with air or by the full or partial decomposition of ammonia to release hydrogen. • As a transport fuel by direct combustion in an engine or through chemical reaction with oxygen in the air in a fuel cell to produce electricity to power a motor. • To store thermal energy through the absorption of water and through phase changes between material states (for example liquid to gas).
Impact of Hydrogen Liquefaction on Hydrogen Fuel Quality for Transport Applications (ISO-14687:2019)
Aug 2022
Publication
Decarbonisation of the energy sector is becoming increasingly more important to the reduction in climate change. Renewable energy is an effective means of reducing CO2 emissions but the fluctuation in demand and production of energy is a limiting factor. Liquid hydrogen allows for long-term storage of energy. Hydrogen quality is important for the safety and efficiency of the end user. Furthermore the quality of the hydrogen gas after liquefaction has not yet been reported. The purity of hydrogen after liquefaction was assessed against the specification of Hydrogen grade D in the ISO-14687:2019 by analysing samples taken at different locations throughout production. Sampling was carried out directly in gas cylinders and purity was assessed using multiple analytical methods. The results indicate that the hydrogen gas produced from liquefaction is of a higher purity than the starting gas with all impurities below the threshold values set in ISO-14687:2019. The amount fraction of water measured in the hydrogen sample increased with repeated sampling from the liquid hydrogen tank suggesting that the sampling system used was affected by low temperatures (−253 ◦C). These data demonstrate for the first time the impact of liquefaction on hydrogen purity assessed against ISO-14687:2019 showing that liquified hydrogen is a viable option for long-term energy storage whilst also improving quality.
The Key Techno-Economic and Manufacturing Drivers for Reducing the Cost of Power-to-Gas and a Hydrogen-Enabled Energy System
Jul 2021
Publication
Water electrolysis is a process which converts electricity into hydrogen and is seen as a key technology in enabling a net-zero compatible energy system. It will enable the scale-up of renewable electricity as a primary energy source for heating transport and industry. However displacing the role currently met by fossil fuels might require a price of hydrogen as low as 1 $/kg whereas renewable hydrogen produced using electrolysis is currently 10 $/kg. This article explores how mass manufacturing of proton exchange membrane (PEM) electrolysers can reduce the capital cost and thus make the production of renewable power to hydrogen gas (PtG) more economically viable. A bottom up direct manufacturing model was developed to determine how economies of scale can reduce the capital cost of electrolysis. The results demonstrated that (assuming an annual production rate of 5000 units of 200 kW PEM electrolysis systems) the capital cost of a PEM electrolysis system can reduce from 1990 $/kW to 590 $/kW based on current technology and then on to 431 $/kW and 300 $/kW based on the an installed capacity scale-up of ten- and one-hundred-fold respectively. A life-cycle costing analysis was then completed to determine the importance of the capital cost of an electrolysis system to the price of hydrogen. It was observed that based on current technology mass manufacturing has a large impact on the price of hydrogen reducing it from 6.40 $/kg (at 10 units units per year) to 4.16 $/kg (at 5000 units per year). Further analysis was undertaken to determine the cost at different installed capacities and found that the cost could reduce further to 2.63 $/kg and 1.37 $/kg based on technology scale-up by ten- and one hundred-fold respectively. Based on the 2030 (and beyond) baseline assumptions it is expected that hydrogen production from PEM electrolysis could be used as an industrial process feed stock provide power and heat to buildings and as a fuel for heavy good vehicles (HGVs). In the cases of retrofitted gas networks for residential or industrial heating solutions or for long distance transport it represents a more economically attractive and mass-scale compatible solution when compared to electrified heating or transport solutions.
Blast Wave Generated by Delayed Ignition of Under-Expanded Hydrogen Free Jet at Ambient and Cryogenic Temperatures
Nov 2022
Publication
An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using available experimental data. The dimensionless blast wave overpressure generated by delayed ignition and the follow-up deflagration or detonation of hydrogen jets at an any location from the jet ∆Pexp/P0 is correlated to the original dimensionless parameter composed of the product of the dimensionless ratio of storage pressure to atmospheric pressure Ps/P0 and the ratio of the jet release nozzle diameter to the distance from the centre of location of the fast-burning near-stoichiometric mixture on the jet axis (30% of hydrogen in the air by volume) to the location of a target (personnel or property) d/Rw. The correlation is built using the analysis of 78 experiments regarding this phenomenon in the wide range of hydrogen storage pressure of 0.5–65.0 MPa and release diameter of 0.5–52.5 mm. The correlation is applicable to hydrogen free jets at ambient and cryogenic temperatures. It is found that the generated blast wave decays inversely proportional to the square of the distance from the fast-burning portion of the jet. The correlation is used to calculate the hazard distances by harm thresholds for five typical hydrogen applications. It is observed that in the case of a vehicle with onboard storage tank at pressure 70 MPa the “no-harm” distance for humans reduces from 10.5 m to 2.6 m when a thermally activated pressure relief device (TPRD) diameter decreases from 2 mm to a diameter of 0.5 mm.
Assessment of Hydrogen Fuel for Rotorcraft Applications
Jun 2022
Publication
This paper presents the application of a multidisciplinary approach for the preliminary design and evaluation of the potential improvements in performance and environmental impact through the utilization of compressed (CGH2) and liquefied (LH2) hydrogen fuel for a civil tilt-rotor modelled after the NASA XV-15. The methodology deployed comprises models for rotorcraft flight dynamics engine performance flight path analysis hydrogen tank and thermal management system sizing. Trade-offs between gravimetric efficiency energy consumption fuel burn CO2 emissions and cost are quantified and compared to the kerosene-fuelled rotorcraft. The analysis carried out suggests that for these vehicle scales gravimetric efficiencies of the order of 13% and 30% can be attained for compressed and liquid hydrogen storage respectively leading to reduced range capability relative to the baseline tilt-rotor by at least 40%. At mission level it is shown that the hydrogen-fuelled configurations result in increased energy consumption by at least 12% (LH2) and 5% (CGH2) but at the same time significantly reduced life-cycle carbon emissions compared to the kerosene counterpart. Although LH2 storage at cryogenic conditions has a higher gravimetric efficiency than CGH2 (at 700 bar) it is shown that for this class of rotorcraft the latter is more energy efficient when the thermal management system for fuel pressurization and heating prior to combustion is accounted for.
Stand-off Detection of Hydrogen Concentration
Sep 2021
Publication
The ability to remotely monitor hydrogen and map its concentration is a pressing challenge in large scale production and distribution as well as other sectors such as nuclear storage. We present a photonicsbased approach for the stand-off sensing and mapping of hydrogen concentration capable of detecting and locating <0.1% concentrations at 100m distance. The technique identifies the wavelength of light resulting from interaction with laser pulses via Raman scattering and can identify a range of other gas species e.g. hydrocarbons ammonia by the spectroscopic analysis of the wavelengths present in the return signal. LIDAR Light Detection and Ranging – analogous to Radar is used for ranging. Laserbased techniques for the stand-off detection of hydrocarbons frequently employ absorption of light at specific wavelengths which are characteristic of the gas species. Unfortunately Hydrogen does not exhibit strong absorption however it does exhibit strong Raman scattering when excited in the UV wavelength range. Raman scattering is a comparatively weak effect. However the use of solid-state detectors capable of detecting single photons known as SPADS (Single Photon Avalanche Photodiode) enables the detection of low concentrations at range while making use of precise time-of-flight range location correlation. The initial safety case which necessitated our development of stand-off hydrogen sensing was the condition monitoring of stored nuclear waste supported and funded by Sellafield and the National Nuclear Laboratory in the UK. A deployable version of the device has been developed and hydrogen characterisation has been carried out in an active nuclear store. Prior to deployment a full ignition risk assessment was carried out. To the best of our knowledge this technique is the strongest candidate for the remote stand-off sensing of hydrogen.
Techno-Economic Analysis of Hydrogen Storage Technologies for Railway Engineering: A Review
Sep 2022
Publication
According to the specific requirements of railway engineering a techno-economic comparison for onboard hydrogen storage technologies is conducted to discuss their feasibility and potentials for hydrogen-powered hybrid trains. Physical storage methods including compressed hydrogen (CH2 ) liquid hydrogen (LH2 ) and cryo-compressed hydrogen (CcH2 ) and material-based (chemical) storage methods such as ammonia liquid organic hydrogen carriages (LOHCs) and metal hydrides are carefully discussed in terms of their operational conditions energy capacity and economic costs. CH2 technology is the most mature now but its storage density cannot reach the final target which is the same problem for intermetallic compounds. In contrast LH2 CcH2 and complex hydrides are attractive for their high storage density. Nevertheless the harsh working conditions of complex hydrides hinder their vehicular application. Ammonia has advantages in energy capacity utilisation efficiency and cost especially being directly utilised by fuel cells. LOHCs are now considered as a potential candidate for hydrogen transport. Simplifying the dehydrogenation process is the important prerequisite for its vehicular employment. Recently increasing novel hydrogen-powered trains based on different hydrogen storage routes are being tested and optimised across the world. It can be forecasted that hydrogen energy will be a significant booster to railway decarbonisation.
Stochastic Low-order Modelling of Hydrogen Autoignition in a Turbulent Non-premixed Flow
Jul 2022
Publication
Autoignition risk in initially non-premixed flowing systems such as premixing ducts must be assessed to help the development of low-NOx systems and hydrogen combustors. Such situations may involve randomly fluctuating inlet conditions that are challenging to model in conventional mixture-fraction-based approaches. A Computational Fluid Dynamics (CFD)-based surrogate modelling strategy is presented here for fast and accurate predictions of the stochastic autoignition behaviour of a hydrogen flow in a hot air turbulent co-flow. The variability of three input parameters i.e. inlet fuel and air temperatures and average wall temperature is first sampled via a space-filling design. For each sampled set of conditions the CFD modelling of the flame is performed via the Incompletely Stirred Reactor Network (ISRN) approach which solves the reacting flow governing equations in post-processing on top of a Large Eddy Simulation (LES) of the inert hydrogen plume. An accurate surrogate model namely a Gaussian Process is then trained on the ISRN simulations of the burner and the final quantification of the variability of autoignition locations is achieved by querying the surrogate model via Monte Carlo sampling of the random input quantities. The results are in agreement with the observed statistics of the autoignition locations. The methodology adopted in this work can be used effectively to quantify the impact of fluctuations and assist the design of practical combustion systems. © 2022 The Authors. Published by Elsevier Inc. on behalf of The Combustion Institute.
Beyond the triangle of renewable Energy Acceptance: The Five Dimensions of Domestic Hydrogen Acceptance
Aug 2022
Publication
The ‘deep’ decarbonization of the residential sector is a priority for meeting national climate change targets especially in countries such as the UK where natural gas has been the dominant fuel source for over half a century. Hydrogen blending and repurposing the national grid to supply low-carbon hydrogen gas may offer respective short- and long-term solutions to achieving emissions reduction across parts of the housing sector. Despite this imperative the social acceptance of domestic hydrogen energy technologies remains underexplored by sustainability scholars with limited insights regarding consumer perceptions and expectations of the transition. A knowledge deficit of this magnitude is likely to hinder effective policymaking and may result in sub-optimal rollout strategies that derail the trajectory of the net zero agenda. Addressing this knowledge gap this study develops a conceptual framework for examining the consumer-facing side of the hydrogen transition. The paper affirms that the spatiotemporal patterns of renewable energy adoption are shaped by a range of interacting scales dimensions and factors. The UK’s emerging hydrogen landscape and its actor-network is characterized as a heterogenous system composed of dynamic relationships and interdependencies. Future studies should engage with domestic hydrogen acceptance as a co-evolving multi-scalar phenomenon rooted in the interplay of five distinct dimensions: attitudinal socio-political community market and behavioral acceptance. If arrived to behavioral acceptance helps realize the domestication of hydrogen heating and cooking established on grounds on cognitive sociopolitical and sociocultural legitimacy. The research community should internalize the complexity and richness of consumer attitudes and responses through a more critical and reflexive approach to the study of social acceptance.
Techno-economic Assessment of Offshore Wind-to-hydrogen Scenarios: A UK Case Study
Jan 2023
Publication
The installed capacity electricity generation from wind and the curtailment of wind power in the UK between 2011 and 2021 showed that penetration levels of wind energy and the amount of energy that is curtailed in future would continue to rise whereas the curtailed energy could be utilised to produce green hydrogen. In this study data were collected technologies were chosen systems were designed and simulation models were developed to determine technical requirements and levelised costs of hydrogen produced and transported through different pathways. The analysis of capital and operating costs of the main components used for onshore and offshore green hydrogen production using offshore wind including alternative strategies for hydrogen storage and transport and hydrogen carriers showed that a significant reduction in cost could be achieved by 2030 enabling the production of green hydrogen from offshore wind at a competitive cost compared to grey and blue hydrogen. Among all scenarios investigated in this study compressed hydrogen produced offshore is the most cost-effective scenario for projects starting in 2025 although the economic feasibility of this scenario is strongly affected by the storage period and the distance to the shore of the offshore wind farm. Alternative scenarios for hydrogen storage and transport such as liquefied hydrogen and methylcyclohexane could become more cost-effective for projects starting in 2050 when the levelised cost of hydrogen could reach values of about £2 per kilogram of hydrogen or lower.
Life Cycle Cost Analysis of an Autonomous Underwater Vehicle that Employs Hydrogen Fuel Cell
Feb 2024
Publication
The use of autonomous vehicles for marine and submarine work has risen considerably in the last decade. Developing new monitoring systems navigation and communications technologies allows a wide range of operational possibilities. Autonomous Underwater Vehicles (AUVs) are being used in offshore missions and applications with some innovative purposes by using sustainable and green energy sources. This paper considers an AUV that uses a hydrogen fuel cell achieving zero emissions. This paper analyses the life cycle cost of the UAV and compares it with a UAV powered by conventional energy. The EN 60300-3-3 guidelines have been employed to develop the cost models. The output results show estimations for the net present value under different scenarios and financial strategies. The study has been completed with the discount rate sensibility analysis in terms of financial viability.
Socio-technical Barriers to Domestic Hydrogen Futures: Repurposing Pipelines, Policies, and Public Perceptions
Feb 2023
Publication
The feasibility of the global energy transition may rest on the ability of nations to harness hydrogen's potential for cross-sectoral decarbonization. In countries historically reliant on natural gas for domestic heating and cooking such as the UK hydrogen may prove critical to meeting net-zero targets and strengthening energy security. In response the UK government is targeting industrial decarbonization via hydrogen with parallel interest in deploying hydrogen-fueled appliances for businesses and homes. However prospective hydrogen futures and especially the domestic hydrogen transition face multiple barriers which reflect the cross-sectoral dynamics of achieving economies of scale and social acceptance. Addressing these challenges calls for a deep understanding of socio-technical factors across different scales of the hydrogen economy. In response this paper develops a socio-technical systems framework for overcoming barriers to the domestic transition which is applied to the UK context. The paper demonstrates that future strategies should account for interactions between political techno-economic technical market and social dimensions of the hydrogen transition. In parallel to techno-economic feasibility the right policies will be needed to create an even playing field for green hydrogen technologies while also supporting stakeholder symbiosis and consumer buy-in. Future studies should grapple with how an effective repurposing of pipelines policies and public perceptions can be aligned to accelerate the development of the hydrogen economy with maximum net benefits for society and the environment.
Next for Net Zero Podcast: Transporting to a Greener World
Oct 2022
Publication
Decarbonisation will need a significant societal shift. The when why and how we travel is going to look very different within a decade. Joining us is Florentine Roy – a leading expert on electric vehicles and Innovation Project Lead at UK Power Networks and Matt Hindle - Head of Net Zero and Sustainability at Wales and West Utilities. Let’s talk about the energy system implications of this massive undertaking and how it can be enabled by innovation in a fair and just way.
The podcast can be found here.
The podcast can be found here.
Notes on the Development of the Hydrogen Supplement to IGEM/TD13 > 7 bar
Nov 2021
Publication
IGEM/TD/13 Standard applies to the safe design construction inspection testing operation and maintenance of pressure regulating installations (PRIs) in accordance with current knowledge and operational experience.
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations:
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations:
- with an upstream maximum operating pressure (MOP) not greater than 100 bar
- with an outlet pressure greater than or equal to 7 bar
- for use with Hydrogen or NG/H blends with a Hydrogen content greater than 10 %
- operating with a temperature range between -20°C and 120°C.
A Justice and Responsible Research and Innovation Exploration of Marine Renewables and Green Hydrogen in Island Communities
Oct 2022
Publication
Both marine renewables and hydrogen are being tested by the European Marine Energy Centre in the Orkney Islands Scotland. Given their emerging nature there is opportunity and risk pertaining to their development and deployment. This research will contribute conceptually and methodologically through the integration of energy justice and RRI conceptual frameworks strengthening justice analyses in relation to emerging energy technologies. This integrated model will be mobilized to critically scrutinize marine energy and green hydrogen as two future energy sources within the energy system. Following a technology-centered exploration of these technologies this work will then contextualise them into place-based considerations of Orkney’s just energy futures. Placing the technologies at the centre of the justice analysis insights will have the potential to inform their development and deployment in other locations. Exploring them within the local Orkney context will initiate an essential and important discussion of energy futures in this specific location. This presentation sets out the empirical and conceptual context for this work and presents a novel conceptual and methodological model combining energy justice and RRI frameworks. Moreover preliminary methods are discussed including methods and outcomes from co-creation workshops held at research design phase.
Batteries, Fuel Cells, or Engines? A Probabilistic Economic and Environmental Assessment of Electricity and Electrofuels for Heavy Goods Vehicles
Oct 2022
Publication
Uncertainty surrounding the total cost of ownership system costs and life cycle environmental impacts means that stakeholders may lack the required information to evaluate the risks of transitioning to low-carbon fuels and powertrains. This paper assesses the life cycle costs and well-to-wheel environmental impacts of using electricity and electrofuels in Heavy Good Vehicles (HGVs) whilst considering input parameter uncertainty. The complex relationship between electricity cost electrolyser capacity factor CO2 capture cost and electricity emissions intensity is assessed within a Monte Carlo based framework to identify scenarios where use of electricity or electrofuels in heavy goods vehicles makes economic and environmental sense. For vehicles with a range of less than 450 km battery electric vehicles achieve the lowest total cost of ownership for an electricity cost less than 100 €/MWh. For vehicles that require a range of up to 900 km hydrogen fuel cell vehicles represent the lowest long-term cost of abatement. Power-to-methane and power-to-liquid scenarios become economically competitive when low-cost electricity is available at high-capacity factors and CO2 capture costs for fuel synthesis are below 100 €/tCO2; these fuels may be more applicable to decarbonise shipping and aviation. Battery electric HGVs reduce greenhouse gas emissions by 50% compared to the diesel baseline with electricity emissions of 350 gCO2e/kWh. Electricity emissions less than 35 gCO2e/kWh are required for the power-to-methane and power-to-liquid scenarios to meet EU emissions savings criteria. High vehicle capital costs and a lack of widespread refuelling infrastructure may hinder initial uptake of low-carbon fuels and powertrains for HGVs.
Global Trade of Hydrogen: What is the Best Way to Transfer Hydrogen Over Long Distances?
Aug 2022
Publication
As a manufactured fuel hydrogen can be produced in a decentralized way in most countries around the world. This means even in a net zero economy the global trade of hydrogen could look quite different to the current international trade in fossil fuels including natural gas. With further declines in the costs of renewable electricity and electrolyzers regions which have lower cost renewable electricity may develop an economic advantage in the production of low-cost hydrogen but for hydrogen to become a globally traded commodity the cost of imports needs to be lower than the cost of domestic production. Unlike oil or natural gas transporting hydrogen over long distances is not an easy task. Hydrogen liquefaction is an extremely energy-intensive process while maintaining the low temperature required for long-distance transportation and storage purposes results in additional energy losses and accompanying costs. The upside is that hydrogen can be converted into multiple carriers that have a higher energy density and higher transport capacity and can potentially be cheaper to transport over long distances. Among the substances currently identified as potential hydrogen carriers suitable for marine shipping liquid ammonia the so-called ‘liquid organic hydrogen carriers’ in general (toluene-methylcyclohexane (MCH) in particular) and methanol have received the most attention in recent years. This paper compares the key techno-economic characteristics of these potential carriers with that of liquified hydrogen in order to develop a better understanding of the ways in which hydrogen could be transported overseas in an efficient manner. The paper also discusses other factors beyond techno-economic features that may affect the choice of optimum hydrogen carrier for long distance transport as well as the global trade of hydrogen.
Hydrogen Storage Vessel for a Proton-Exchange Membrane (PEM) Fuel Cell Auxiliary Power Unit for Commercial Aircraft
Jul 2025
Publication
Approximately 20% of emissions from air travel are attributed to the auxiliary power units (APUs) carried in commercial aircraft. This paper proposes to reduce greenhouse gas emissions in international air transport by adopting proton-exchange membrane (PEM) fuel cells to replace APUs in commercial aircraft: we consider the design of three compressed hydrogen storage vessels made of 304 stainless steel 6061-T6 aluminium and Grade 5 (Ti-6Al-4V) titanium and capable of delivering 440 kW—enough for a PEM fuel cell for a Boeing 777. Complete structural analyses for pressures from 35 MPa to 70 MPa and wall thicknesses of 25 50 100 and 150 mm are used to determine the optimal material for aviation applications. Key factors such as deformation safety factors and Von Mises equivalent stress are evaluated to ensure structural integrity under a range of operating conditions. In addition CO2 emissions from a conventional 440 kW gas turbine APU and an equivalent PEM fuel cell are compared. This study provides insights into optimal material selection for compressed hydrogen storage vessels emphasising safety reliability cost and weight reduction. Ultimately this research aims to facilitate the adoption of fuel cell technology in aviation contributing to greenhouse emissions reduction and hence sustainable air transport.
Solar Hydrogen Fuel Generation from Wastewater—Beyond Photoelectrochemical Water Splitting: A Perspective
Oct 2022
Publication
Green hydrogen—a carbon-free renewable fuel—has the capability to decarbonise a variety of sectors. The generation of green hydrogen is currently restricted to water electrolysers. The use of freshwater resources and critical raw materials however limits their use. Alternative water splitting methods for green hydrogen generation via photocatalysis and photoelectrocatalysis (PEC) have been explored in the past few decades; however their commercial potential still remains unexploited due to the high hydrogen generation costs. Novel PEC-based simultaneous generation of green hydrogen and wastewater treatment/high-value product production is therefore seen as an alternative to conventional water splitting. Interestingly the organic/inorganic pollutants in wastewater and biomass favourably act as electron donors and facilitate the dual-functional process of recovering green hydrogen while oxidising the organic matter. The generation of green hydrogen through the dual-functional PEC process opens up opportunities for a “circular economy”. It further enables the end-of-life commodities to be reused recycled and resourced for a better life-cycle design while being economically viable for commercialisation. This review brings together and critically analyses the recent trends towards simultaneous wastewater treatment/biomass reforming while generating hydrogen gas by employing the PEC technology. We have briefly discussed the technical challenges associated with the tandem PEC process new avenues techno-economic feasibility and future directions towards achieving net neutrality.
Ammonia, Methane and Hydrogen for Gas Turbines
Aug 2015
Publication
Ammonia has been identified as a sustainable fuel for transport and power applications. Similar to hydrogen ammonia is a synthetic product that can be obtained either from fossil fuels biomass or other renewable sources. Since the 1960’s considerable research has taken place to develop systems capable of burning the material in gas turbines. However it is not until recently that interest in ammonia has regained some momentum in the energy agenda as it is a carbon free carrier and offers an energy density higher than compressed hydrogen. . Therefore this work examines combustion stability and emissions from gaseous ammonia blended with methane or hydrogen in gas turbines. Experiments were carried out in a High Pressure Combustion Rig under atmospheric conditions employing a bespoke generic swirl burner. OH* Chemiluminescense was used for all trials to determine reactivity of the radical. Emissions were measured and correlated to equilibrium calculations using GASEQ. Results show that efficient combustion can be achieved with high power but at very narrow equivalence ratios using both hydrogen and methane blends. Moreover low concentrations of OH radicals are observed at high hydrogen content probably as a consequence of the high NH2 production.
Recent Progress in Ammonia Fuel Cells and their Potential Applications
Nov 2020
Publication
Conventional technologies are largely powered by fossil fuel exploitation and have ultimately led to extensive environmental concerns. Hydrogen is an excellent carbon-free energy carrier but its storage and long-distance transportation remain big challenges. Ammonia however is a promising indirect hydrogen storage medium that has well-established storage and transportation links to make it an accessible fuel source. Moreover the notion of ‘green ammonia’ synthesised from renewable energy sources is an emerging topic that may open significant markets and provide a pathway to decarbonise a variety of applications reliant on fossil fuels. Herein a comparative study based on the chosen design working principles advantages and disadvantages of direct ammonia fuel cells is summarised. This work aims to review the most recent advances in ammonia fuel cells and demonstrates how close this technology type is to integration with future applications. At present several challenges such as material selection NOx formation CO2 tolerance limited power densities and long-term stability must still be overcome and are also addressed within the contents of this review
Perspective on the Hydrogen Economy as a Pathway to Reach Net-zero CO2 Emissions in Europe
Jan 2022
Publication
The envisioned role of hydrogen in the energy transition – or the concept of a hydrogen economy – has varied through the years. In the past hydrogen was mainly considered a clean fuel for cars and/or electricity production; but the current renewed interest stems from the versatility of hydrogen in aiding the transition to CO2 neutrality where the capability to tackle emissions from distributed applications and complex industrial processes is of paramount importance. However the hydrogen economy will not materialise without strong political support and robust infrastructure design. Hydrogen deployment needs to address multiple barriers at once including technology development for hydrogen production and conversion infrastructure co-creation policy market design and business model development. In light of these challenges we have brought together a group of hydrogen researchers who study the multiple interconnected disciplines to offer a perspective on what is needed to deploy the hydrogen economy as part of the drive towards net-zero-CO2 societies. We do this by analysing (i) hydrogen end-use technologies and applications (ii) hydrogen production methods (iii) hydrogen transport and storage networks (iv) legal and regulatory aspects and (v) business models. For each of these we provide key take home messages ranging from the current status to the outlook and needs for further research. Overall we provide the reader with a thorough understanding of the elements in the hydrogen economy state of play and gaps to be filled.
Strategic Transport Fleet Analysis of Heavy Goods Vehicle Technology for Net-zero Targets
Jul 2022
Publication
This paper addresses the decarbonisation of the heavy-duty transport sector and develops a strategy towards net-zero greenhouse gas (GHG) emissions in heavy-goods vehicles (HGVs) by 2040. By conducting a literature review and a case study on the vehicle fleet of a large UK food and consumer goods retailer the feasibilities of four alternative vehicle technologies are evaluated from environmental economic and technical perspectives. Socio-political factors and commercial readiness are also examined to capture non-technical criteria that influences decision-makers. Strategic analysis frameworks such as PEST-SWOT models were developed for liquefied natural gas biomethane electricity and hydrogen to allow a holistic comparison and identify their long-term deployment potential. Technology innovation is needed to address range and payload limitations of electric trucks whereas government and industry support are essential for a material deployment of hydrogen in the 2030s. Given the UK government’s plan to phase out new diesel HGVs by 2040 fleet operators should commence new vehicle trials by 2025 and replace a considerable amount of their lighter diesel trucks with zero-emission vehicles by 2030 and the remaining heavier truck fleet by 2035.
Cushion Gas in Hydrogen Storage—A Costly CAPEX or a Valuable Resource for Energy Crises?
Dec 2022
Publication
The geological storage of hydrogen is a seasonal energy storage solution and the storage capacity of saline aquifers is most appropriately defined by quantifying the amount of hydrogen that can be injected and reproduced over a relevant time period. Cushion gas stored in the reservoir to support the production of the working gas is a CAPEX which should be reduced to decrease implementation cost for gas storage. The cushion gas to working gas ratio provides a sufficiently accurate reflection of the storage efficiency with higher ratios equating to larger initial investments. This paper investigates how technical measures such as well configurations and adjustments to the operational size and schedule can reduce this ratio and the outcomes can inform optimisation strategies for hydrogen storage operations. Using a simplified open saline aquifer reservoir model hydrogen storage is simulated with a single injection and production well. The results show that the injection process is more sensitive to technical measures than the production process; a shorter perforation and a smaller well diameter increases the required cushion gas for the injection process but has little impact on the production. If the storage operation capacity is expanded and the working gas volume increased the required cushion gas to working gas ratio increases for injection reducing the efficiency of the injection process. When the reservoir pressure has more time to equilibrate less cushion gas is required. It is shown that cushion gas plays an important role in storage operations and that the tested optimisation strategies impart only minor effects on the production process however there is significant need for careful optimisation of the injection process. It is suggested that the recoverable part of the cushion gas could be seen as a strategic gas reserve which can be produced during an energy crisis. In this scenario the recoverable cushion gas could be owned by the state and the upfront costs for gas storage to the operator would be reduced making the implementation of more gas storage and the onset of hydrogen storage more attractive to investors.
Maximizing Green Hydrogen Production from Water Electrocatalysis: Modeling and Optimization
Mar 2023
Publication
The use of green hydrogen as a fuel source for marine applications has the potential to significantly reduce the carbon footprint of the industry. The development of a sustainable and cost-effective method for producing green hydrogen has gained a lot of attention. Water electrolysis is the best and most environmentally friendly method for producing green hydrogen-based renewable energy. Therefore identifying the ideal operating parameters of the water electrolysis process is critical to hydrogen production. Three controlling factors must be appropriately identified to boost hydrogen generation namely electrolysis time (min) electric voltage (V) and catalyst amount (µg). The proposed methodology contains the following two phases: modeling and optimization. Initially a robust model of the water electrolysis process in terms of controlling factors was established using an adaptive neuro-fuzzy inference system (ANFIS) based on the experimental dataset. After that a modern pelican optimization algorithm (POA) was employed to identify the ideal parameters of electrolysis duration electric voltage and catalyst amount to enhance hydrogen production. Compared to the measured datasets and response surface methodology (RSM) the integration of ANFIS and POA improved the generated hydrogen by around 1.3% and 1.7% respectively. Overall this study highlights the potential of ANFIS modeling and optimal parameter identification in optimizing the performance of solar-powered water electrocatalysis systems for green hydrogen production in marine applications. This research could pave the way for the more widespread adoption of this technology in the marine industry which would help to reduce the industry’s carbon footprint and promote sustainability.
Cost and Thermodynamic Analysis of Wind-Hydrogen Production via Multi-energy Systems
Mar 2024
Publication
With rising temperatures extreme weather events and environmental challenges there is a strong push towards decarbonization and an emphasis on renewable energy with wind energy emerging as a key player. The concept of multi-energy systems offers an innovative approach to decarbonization with the potential to produce hydrogen as one of the output streams creating another avenue for clean energy production. Hydrogen has significant potential for decarbonizing multiple sectors across buildings transport and industries. This paper explores the integration of wind energy and hydrogen production particularly in areas where clean energy solutions are crucial such as impoverished villages in Africa. It models three systems: distinct configurations of micro-multi-energy systems that generate electricity space cooling hot water and hydrogen using the thermodynamics and cost approach. System 1 combines a wind turbine a hydrogen-producing electrolyzer and a heat pump for cooling and hot water. System 2 integrates this with a biomass-fired reheat-regenerative power cycle to balance out the intermittency of wind power. System 3 incorporates hydrogen production a solid oxide fuel cell for continuous electricity production an absorption cooling system for refrigeration and a heat exchanger for hot water production. These systems are modeled with Engineering Equation Solver and analyzed based on energy and exergy efficiencies and on economic metrics like levelized cost of electricity (LCOE) cooling (LCOC) refrigeration (LCOR) and hydrogen (LCOH) under steady-state conditions. A sensitivity analysis of various parameters is presented to assess the change in performance. Systems were optimized using a multiobjective method with maximizing exergy efficiency and minimizing total product unit cost used as objective functions. The results show that System 1 achieves 79.78 % energy efficiency and 53.94 % exergy efficiency. System 2 achieves efficiencies of 55.26 % and 27.05 % respectively while System 3 attains 78.73 % and 58.51 % respectively. The levelized costs for micro-multi-energy System 1 are LCOE = 0.04993 $/kWh LCOC = 0.004722 $/kWh and LCOH = 0.03328 $/kWh. For System 2 these values are 0.03653 $/kWh 0.003743 $/kWh and 0.03328 $/kWh. In the case of System 3 they are 0.03736 $/kWh 0.004726 $/kWh and 0.03335 $/kWh and LCOR = 0.03309 $/kWh. The results show that the systems modeled here have competitive performance with existing multi-energy systems powered by other renewables. Integrating these systems will further the sustainable and net zero energy system transition especially in rural communities.
Sustainable Ammonia Production Processes
Mar 2021
Publication
Due to the important role of ammonia as a fertilizer in the agricultural industry and its promising prospects as an energy carrier many studies have recently attempted to find the most environmentally benign energy efficient and economically viable production process for ammonia synthesis. The most commonly utilized ammonia production method is the Haber-Bosch process. The downside to this technology is the high greenhouse gas emissions surpassing 2.16 kgCO2-eq/kg NH3 and high amounts of energy usage of over 30 GJ/tonne NH3 mainly due to the strict operational conditions at high temperature and pressure. The most widely adopted technology for sustainable hydrogen production used for ammonia synthesis is water electrolysis coupled with renewable technologies such as wind and solar. In general a water electrolyzer requires a continuous supply of pretreated water with high purity levels for its operation. Moreover for production of 1 tonne of hydrogen 9 tonnes of water is required. Based on this data for the production of the same amount of ammonia through water electrolysis 233.6 million tonnes/yr of water is required. In this paper a critical review of different sustainable hydrogen production processes and emerging technologies for sustainable ammonia synthesis along with a comparative life cycle assessment of various ammonia production methods has been carried out. We find that through the review of each of the studied technologies either large amounts of GHG emissions are produced or high volumes of pretreated water is required or a combination of both these factors occur.
Thermocatalytic Hydrogen Production Through Decomposition of Methane-A Review
Oct 2021
Publication
Consumption of fossil fuels especially in transport and energy-dependent sectors has led to large greenhouse gas production. Hydrogen is an exciting energy source that can serve our energy purposes and decrease toxic waste production. Decomposition of methane yields hydrogen devoid of COx components thereby aiding as an eco-friendly approach towards large-scale hydrogen production. This review article is focused on hydrogen production through thermocatalytic methane decomposition (TMD) for hydrogen production. The thermodynamics of this approach has been highlighted. Various methods of hydrogen production from fossil fuels and renewable resources were discussed. Methods including steam methane reforming partial oxidation of methane auto thermal reforming direct biomass gasification thermal water splitting methane pyrolysis aqueous reforming and coal gasification have been reported in this article. A detailed overview of the different types of catalysts available the reasons behind their deactivation and their possible regeneration methods were discussed. Finally we presented the challenges and future perspectives for hydrogen production via TMD. This review concluded that among all catalysts nickel ruthenium and platinum-based catalysts show the highest activity and catalytic efficiency and gave carbon-free hydrogen products during the TMD process. However their rapid deactivation at high temperatures still needs the attention of the scientific community.
The Hydrogen Bike: Communicating the Production and Safety of Green Hydrogen
Mar 2021
Publication
As the international community aims to reduce its reliance on fossil fuels green hydrogen has great potential to replace methane as a clean source of fuel. A novel public engagement activity The Hydrogen Bike has been developed to demonstrate the production and use of green hydrogen from water. The aim of the activity is to educate entertain and inform young people and adults so that they have an opportunity to form an opinion about the use of hydrogen as a fuel. Using a novel two-part data collection system participants are briefly surveyed for their opinion on hydrogen before and after participating in The Hydrogen Bike activity. Through this we have found that most participants (73%) are considered to have no opinion or a neutral opinion on hydrogen before participating in The Hydrogen Bike activity. After participation 88% of those who were originally neutral or had no opinion on hydrogen self-reported a positive feeling about hydrogen. The method of data collection was quick intuitive and suitable for an audience attracted from passing footfall.
Risk Perception of an Emergent Technology: The Case of Hydrogen Energy
Jan 2006
Publication
Although hydrogen has been used in industry for many years as a chemical commodity its use as a fuel or energy carrier is relatively new and expert knowledge about its associated risks is neither complete nor consensual. Public awareness of hydrogen energy and attitudes towards a future hydrogen economy are yet to be systematically investigated. This paper opens by discussing alternative conceptualisations of risk then focuses on issues surrounding the use of emerging technologies based on hydrogen energy. It summarises expert assessments of risks associated with hydrogen. It goes on to review debates about public perceptions of risk and in doing so makes comparisons with public perceptions of other emergent technologies—Carbon Capture and Storage (CCS) Genetically Modified Organisms and Food (GM) and Nanotechnology (NT)—for which there is considerable scientific uncertainty and relatively little public awareness. The paper finally examines arguments about public engagement and "upstream" consultation in the development of new technologies. It is argued that scientific and technological uncertainties are perceived in varying ways and different stakeholders and different publics focus on different aspects or types of risk. Attempting to move public consultation further "upstream" may not avoid this because the framing of risks and benefits is necessarily embedded in a cultural and ideological context and is subject to change as experience of the emergent technology unfolds.
Evidence Base Utilised to Justify a Hydrogen Blend Gas Network Safety Case
Sep 2021
Publication
Blending hydrogen with natural gas up to 20 % mol/mol has been identified as a key enabler of hydrogen deployment within the UK gas network. This work outlines the evidence base generated to form the basis of safety submitted to the Health and Safety Executive (HSE) to justify a demonstration of hydrogen blending on a live public gas network within the UK supplying a hydrogen blend to 668homes over the course of 10 months. An evidence base to demonstrate that gas users are not prejudiced by the addition of hydrogen is required by the Gas Safety (Management) Regulations [1] to allow hydrogen distribution above the 0.1 mol% limit specified within the regulations. The technical evidence generated to support the safety case presented to the HSE concerned the implications of introducing a hydrogen blend on appliance operation materials gas characteristics and operational procedures. The outputs of the technical evidence workstreams provided input data to a Quantitative Risk Assessment (QRA) of the GB gas distribution network. The QRA was developed in support of the safety case to allow a causal understanding of public risk to be understood where harm due to gas usage was defined as risk to life caused either by carbon monoxide poisoning or as a result of fires/explosions. Public records were used to calibrate and validate the base risk model to understand the dynamics of public risk due to natural gas usage. The experimental and analytical results of the technical workstreams were then used to derive risk model inputs relating to a hydrogen blend. This allowed a quantified comparison of risk to be understood to demonstrate parity of safety between natural gas and a hydrogen blend. This demonstration of risk parity is a condition precedent of allowing the distribution and utilisation of hydrogen blends within the GB gas network.
Techno Environmental Assessment of Flettner Rotor as Assistance Propulsion System for LH2 Tanker Ship Fuelled by Hydrogen
Nov 2022
Publication
This study presents a novel design and development of a 280000 m3 liquefied hydrogen tanker ship by implementing a set of 6 Flettner rotors as an assistance propulsion system in conjunction with a combined-cycle gas turbine fuelled by hydrogen as a prime mover. The study includes assessment of the technical and environmental aspects of the developed design. Furthermore an established method was applied to simulate the LH2 tanker in different voyages and conditions to investigate the benefits of harnessing wind energy to assist combined-cycle gas turbine in terms of performance and emission reduction based on engine behaviour for different voyages under loaded and unloaded normal as well as 6 % degraded engine and varying ambient conditions. The results indicate that implementing a set of 6 Flettner rotors for the LH2 tanker ship has the potential to positively impact the performance and lead to environmental benefits. A maximum contribution power of around 1.8 MW was achieved in the winter season owing to high wind speed and favourable wind direction. This power could save approximately 3.6 % of the combined-cycle gas turbine total output power (50 MW) and cause a 3.5 % reduction in NOx emissions.
Combustion Characterization of Hybrid Methane-hydrogen Gas in Domestic Swirl Stoves
Oct 2022
Publication
Combustion of hybrid natural gas (methane) and hydrogen mixture in domestic swirl stoves has been characterized using hot-state experiments and numerical analysis. The detailed combustion mechanism of methane and hydrogen (GRI-Mech 3.0) has been simplified to obtain reduced number of chemical reactions involved (82 % reduction). The novel simplified combustion mechanism developed has been used to obtain combustion characteristics of hybrid methane-hydrogen mixture. The difference between the calculations from the detailed and the simplified mechanisms has been found to be Combustion of hybrid natural gas (methane) and hydrogen mixture in domestic swirl stoves has been characterized using hot-state experiments and numerical analysis. The detailed combustion mechanism of methane and hydrogen (GRI-Mech 3.0) has been simplified to obtain reduced number of chemical reactions involved (82 % reduction). The novel simplified combustion mechanism developed has been used to obtain combustion characteristics of hybrid methane-hydrogen mixture. The difference between the calculations from the detailed and the simplified mechanisms has been found to be <1 %. A numerical model based on the simplified combustion model is developed rigorously tested and validated against hot-state tests. The results depict that the maximum difference in combustion zone’s average temperature is <13 %. The investigations have then been extended to hybrid methane-hydrogen mixtures with varying volume fraction of hydrogen. The results show that for a mixture containing 15 % hydrogen the release of CO due to combustion reduces by 25 % while the combustion zone’s average temperature reduces by 6.7 %. The numerical results and hot-state tests both confirm that the temperature remains stable when hybrid methane-hydrogen mixture is used in domestic swirl gas stoves demonstrating its effectiveness in cooking processes.
Future Pathways for Energy Networks: A Review of International Experiences in High Income Countries
Oct 2022
Publication
Energy networks are the systems of pipes and wires by which different energy vectors are transported from where they are produced to where they are needed. As such these networks are central to facilitating countries’ moves away from a reliance on fossil fuels to a system based around the efficient use of renewable and other low carbon forms of energy. In this review we highlight the challenges facing energy networks from this transition in a sample of key high income countries. We identify the technical and other innovations being implemented to meet these challenges and describe some of the new policy and regulatory developments that are incentivising the required changes. We then review evidence from the literature about the benefits of moving to a more integrated approach based on the concept of a Multi-Vector Energy Network (MVEN). Under this approach the different networks are planned and operated together to achieve greater functionality and performance than simply the sum of the individual networks. We find that most studies identify a range of benefits from an MVEN approach but that these findings are based on model simulations. Further work is therefore needed to verify whether the benefits can be realised in practice and to identify how any risks can be mitigated.
Effect of TPRD Diameter and Direction of Release on Hydrogen Dispersion in Underground Parking
Sep 2021
Publication
Unignited hydrogen release in underground parking could be considered inherently safer if the safety strategy to avoid the formation of the flammable hydrogen-air mixture under a ceiling is followed. This strategy excludes destructive deflagrative combustion and associated pressure and thermal effects in the case of ignition. This paper aims at understanding the effects of the thermally activated pressure relieve device (TPRD) diameter and direction of release on the build-up of hydrogen flammable concentration under the ceiling in the presence of mechanical ventilation required for underground parking. The study employs the similarity law for hydrogen jet concentration decay in a free under-expanded jet to find the lower limit of TPRD diameter that excludes the formation of a flammable mixture under the ceiling during upward release. This approach is conservative and does not include the effect of mechanical ventilation providing flow velocity around a few meters per second which is significantly below velocities in hydrogen momentum-dominated under-expanded jets. Hydrogen releases downwards under a vehicle at different angles and with different air velocities due to mechanical ventilation were investigated using computational fluid dynamics (CFD). The joint effect of TPRD diameter release direction and mechanical ventilation is studied. TPRD diameters for the release of hydrogen upwards and downwards preventing the creation of flammable hydrogen-air mixture under the parking ceiling are defined for different ceiling heights and locations of TPRD above the floor. Recommendations to the design of TPRD devices to underpin the safe introduction of hydrogen fuelled vehicles in currently existing underground parking and infrastructure are formulated."
Metal-Hydride-Based Hydrogen Storage as Potential Heat Source for the Cold Start of PEM FC in Hydrogen-Powered Coaches: A Comparative Study of Various Materials and Thermal Management Techniques
Nov 2022
Publication
The successful and fast start-up of proton exchange membrane fuel cells (PEMFCs) at subfreezing temperatures (cold start) is very important for the use of PEMFCs as energy sources for automotive applications. The effective thermal management of PEMFCs is of major importance. When hydrogen is stored in hydride-forming intermetallics significant amounts of heat are released due to the exothermic nature of the reaction. This excess of heat can potentially be used for PEMFC thermal management and to accelerate the cold start. In the current work this possibility is extensively studied. Three hydride-forming intermetallics are introduced and their hydrogenation behavior is evaluated. In addition five thermal management scenarios of the metal hydride beds are studied in order to enhance the kinetics of the hydrogenation. The optimum combination of the intermetallic hydrogenation behavior weight and complexity of the thermal management system was chosen for the study of thermal coupling with the PEMFCs. A 1D GT-SUITE model was built to stimulate the thermal coupling of a 100 kW fuel cell stack with the metal hydride. The results show that the use of the heat from the metal hydride system was able to reduce the cold start by up to 8.2%.
Estimates of the Decarbonization Potential of Alternative Fuels for Shipping as a Function of Vessel Type, Cargo, and Voyage
Oct 2022
Publication
Fuel transition can decarbonize shipping and help meet IMO 2050 goals. In this paper HFO with CCS LNG with CCS bio-methanol biodiesel hydrogen ammonia and electricity were studied using empirical ship design models from a fleet-level perspective and at the Tank-ToWake level to assist operators technology developers and policy makers. The cargo attainment rate CAR (i.e. cargo that must be displaced due to the low-C propulsion system) the ES (i.e. TTW energy needed per ton*n.m.) the CS (economic cost per ton*n.m.) and the carbon intensity index CII (gCO2 per ton*n.m.) were calculated so that the potential of the various alternatives can be compared quantitatively as a function of different criteria. The sensitivity of CAR towards ship type fuel type cargo type and voyage distance were investigated. All ship types had similar CAR estimates which implies that considerations concerning fuel transition apply equally to all ships (cargo containership tankers). Cargo type was the most sensitive factor that made a ship either weight or volume critical indirectly impacting on the CAR of different fuels; for example a hydrogen ship is weight-critical and has 2.3% higher CAR than the reference HFO ship at 20000 nm. Voyage distance and fuel type could result in up to 48.51% and 11.75% of CAR reduction. In addition to CAR the ES CS and CII for a typical mission were calculated and it was found that HFO and LNG with CCS gave about 20% higher ES and CS than HFO and biodiesel had twice the cost while ammonia methanol and hydrogen had 3–4 times the CS of HFO and electricity about 20 times suggesting that decarbonisation of the world’s fleet will come at a large cost. As an example of including all factors in an effort to create a normalized scoring system an equal weight was allocated to each index (CAR ES CS and CII). Biodiesel achieved the highest score (80%) and was identified as the alternative with the highest potential for a deep-seagoing containership followed by ammonia hydrogen bio-methanol and CCS. Electricity has the lowest normalized score of 33%. A total of 100% CAR is achievable by all alternative fuels but with compromises in voyage distance or with refuelling. For example a battery containership carrying an equal amount of cargo as an HFO-fuelled containership can only complete 13% of the voyage distance or needs refuelling seven times to complete 10000 n.m. The results can guide decarbonization strategies at the fleet level and can help optimise emissions as a function of specific missions.
Application of Pipeline QRA Methodologies to Hydrogen Pipelines in Support of the Transition to a Decarbonised Future
Sep 2021
Publication
Hydrogen is expected to play a key role in the decarbonised future of energy. For hydrogen distribution pipelines are seen as the main method for mass transport of hydrogen gas. To support the evaluation of risk related to hydrogen pipelines a revised QRA methodology is presented based on currently available and industry accepted guidance related to natural gas. The QRA approach is primarily taken from HSE UK’s MISHAP methodology [1]. The base methodology is reviewed and modifications suggested to adapt it for use with hydrogen gas transport. Compared to natural gas it was found that the escape distances for hydrogen (based on the degree of heat flux) were lower. However as for the overall risk for both individual and societal the case with hydrogen was more severe close to the pipeline. This was driven by the increased ignition probability of hydrogen. The approach may be used as part of the review and appraisal process of hydrogen projects
Enabling or Requiring Hydrogen-ready Industrial Boiler Equipment: Call for Evidence, Summary of Responses
Dec 2022
Publication
On 20 December 2021 the Department for Business Energy and Industrial Strategy (BEIS) launched a Call for Evidence (CfE) on enabling or requiring hydrogen-ready industrial boiler equipment. The aim was to gather evidence from a broad range of UK manufacturers industrial end-users supply chain participants and other experts to enable the development of proposals. The CfE was open for 12 weeks closing on 14 March 2022. The CfE followed the publication of the UK Hydrogen Strategy on 17 August 2021. In the Strategy government committed to run a CfE on hydrogen-ready industrial equipment by theend of 2022. The published CfE focussed on industrial boilers due to their widespread use and because BEIS analysis indicates a significant proportion of the demand for hydrogen in industry will come from this equipment category. Furthermore the technology required for hydrogen boilers is relatively advanced and more standardised than for other types of industrial<br/>equipment. For these reasons industrial boiler equipment presents a good test case for hydrogen-ready industrial equipment more broadly.<br/>The CfE contained the following three sections:<br/>• The opportunity for hydrogen-ready industrial boilers<br/>• The role for government to support hydrogen-ready industrial boiler equipment<br/>• The role of the supply chain and economic opportunities for the UK<br/>Respondents were asked to support their answers with evidence relating to their business product or sector published literature studies or to their broader expertise. To raise awareness of the CfE BEIS officials held two online webinars on 1 February 2022 and 3 February 2022. These were open to boiler manufacturers industrial end-users supply chain participants trade associations professional bodies and any other person(s) with an interest in the area.<br/>To build on evidence gathered through the CfE BEIS commissioned an independent study from Arup and Kiwa Gastec to further examine whether government should enable or require hydrogen-ready industrial boiler equipment. This study investigated the following topics:<br/>• definitions of hydrogen-readiness for industrial boilers<br/>• comparisons of the cost and resource requirement to install and convert hydrogen-ready industrial boiler equipment<br/>• industrial boiler supply chain capacity for conversion to hydrogen<br/>• estimates of the UK industrial boiler population<br/>The final report for this study has been published alongside the government response to the call for evidence. The conclusions and recommendations of that report do not necessarily represent the view of BEIS.
Hydrogen Strategy Update to the Market: December 2022
Dec 2022
Publication
The Government is committed to developing the UK’s low carbon hydrogen economy: hydrogen is considered critical to delivering energy security and our decarbonisation targets and presents a significant growth opportunity. It can play a pivotal role in our transition to a future based on renewable and nuclear energy while ensuring that natural gas used during this transition is from reliable sources including our own North Sea production and can provide clean energy for use in industry power transport and potentially home heating. In the UK Hydrogen Strategy we included the commitment to regularly summarise our policy development to keep industry apprised. Since publication of the Hydrogen Strategy we have doubled our low carbon hydrogen production capacity ambition to up to 10GW by 2030 (with at least half from electrolytic hydrogen) in the British Energy Security Strategy provided greater clarity to investors through the Hydrogen Investment Package and made substantial policy and funding strides across the hydrogen value chain. We summarised these ambitions commitments and actions in the first Hydrogen Strategy update to the market in July 2022. This was published alongside other key elements of our policy support which also included the launch of the first Electrolytic Hydrogen Allocation Round – offering joint Net Zero Hydrogen Fund (NZHF) and Hydrogen Production Business Model (HPBM) support – and our Hydrogen Sector Development Action Plan and the appointment of a UK Hydrogen Champion. Hydrogen is closely integrated into Government’s wider policy development on energy security and the energy transition both domestically and internationally with hydrogen policy previously announced through the Net Zero Strategy and the Breakthrough Agenda at COP26. This December 2022 Hydrogen Strategy update to the market summarises the extensive activity across Government since July to develop new hydrogen policy at pace and to design and deliver funding support. This includes announcements on shortlisted hydrogen projects in the Cluster Sequencing Process the launch of a consultation on hydrogen transport and storage (T&S) infrastructure the publication of the HPBM Heads of Terms and an update on the ongoing first Electrolytic Hydrogen Allocation Round. The hydrogen policy development presented here underlines the Government’s approach to promote every aspect of the UK hydrogen economy in collaboration with industry investors and international partners to create a strong globally competitive UK hydrogen sector.
Decarbonisation of Heavy-duty Diesel Engines Using Hydrogen Fuel: A Review of the Potential Impact NOx Emissions
Jul 2022
Publication
As countries seek ways to meet climate change commitments hydrogen fuel offers a low-carbon alternative for sectors where battery electrification may not be viable. Blending hydrogen with fossil fuels requires only modest technological adaptation however since combustion is retained nitrogen oxides (NOx) emissions remain a potential disbenefit. We review the potential air quality impacts arising from the use of hydrogen–diesel blends in heavy-duty diesel engines a powertrain which lends itself to hydrogen co-fuelling. Engine load is identified as a key factor influencing NOx emissions from hydrogen–diesel combustion in heavy-duty engines although variation in other experimental parameters across studies complicates this relationship. Combining results from peer-reviewed literature allows an estimation to be made of plausible NOx emissions from hydrogen–diesel combustion relative to pure-diesel combustion. At 0–30% engine load which encompasses the average load for mobile engine applications NOx emissions changes were in the range 59 to +24% for a fuel blend with 40 e% hydrogen. However at 50–100% load which approximately corresponds to stationary engine applications NOx emissions changes were in the range 28 to +107%. Exhaust gas recirculation may be able to reduce NOx emissions at very high and very low loads when hydrogen is blended with diesel and existing exhaust aftertreatment technologies are also likely to be effective. Recent commercial reporting on the development of hydrogen and hydrogen–diesel dual fuel combustion in large diesel engines are also summarised. There is currently some disconnection between manufacturer reported impacts of hydrogen-fuelling on NOx emissions (always lower emissions) and the conclusions drawn from the peer reviewed literature (frequently higher emissions).
The Role of Hydrogen for Deep Decarbonization of Energy Systems: A Chilean Case Study
Mar 2023
Publication
In this paper we implement a long-term multi-sectoral energy planning model to evaluate the role of green hydrogen in the energy mix of Chile a country with a high renewable potential under stringent emission reduction objectives in 2050. Our results show that green hydrogen is a cost-effective and environmentally friendly route especially for hard-to-abate sectors such as interprovincial and freight transport. They also suggest a strong synergy of hydrogen with electricity generation from renewable sources. Our numerical simulations show that Chile should (i) start immediately to develop hydrogen production through electrolyzers all along the country (ii) keep investing in wind and solar generation capacities ensuring a low cost hydrogen production and reinforce the power transmission grid to allow nodal hydrogen production (iii) foster the use of electric mobility for cars and local buses and of hydrogen for long-haul trucks and interprovincial buses and (iv) develop seasonal hydrogen storage and hydrogen cells to be exploited for electricity supply especially for the most stringent emission reduction objectives.
Probabilistic Modelling of Seasonal Energy Demand Patterns in the Transition from Natural Gas to Hydrogen for an Urban Energy District
May 2023
Publication
The transition to a low-carbon energy system can be depicted as a “great reconfiguration” from a socio-technical perspective that carries the risk of impact shifts. Electrification with the objective of achieving rapidly deep decarbonisation must be accompanied by effective efficiency and flexibility measures. Hydrogen can be a preferred option in the decarbonisation process where electrification of end-uses is difficult or impractical as well as for long-term storage in energy infrastructure characterised by a large penetration of renewable energy sources. Notwithstanding the current uncertainties regarding costs environmental impact and the inherent difficulties of increasing rapidly supply capacity hydrogen can represent a solution to be used in multi-energy systems with combined heat and power (CHP) in particular in urban energy districts. In fact while achieving carbon savings with natural gas fuelled CHP is not possible when low grid carbon intensity factors are present it may still be possible to use it to provide flexibility services and to reduce emissions further with switch from natural gas to hydrogen. In this paper a commercially established urban district energy scheme located in Southampton (United Kingdom) is analysed with the goal of exploring potential variations in its energy demand. The study proposes the use of scalable data-driven methods and probabilistic simulation to generate seasonal energy demand patterns representing the potential short-term and long-term evolution of the energy district.
A Review of the Role of Hydrogen in the Heat Decarbonization of Future Energy Systems: Insights and Perspectives
Apr 2024
Publication
Hydrogen is an emerging technology changing the context of heating with cleaner combustion than traditional fossil fuels. Studies indicate the potential to repurpose the existing natural gas infrastructure offering consumers a sustainable economically viable option in the future. The integration of hydrogen in combined heat and power systems could provide residential energy demand and reduce environmental emissions. However the widespread adoption of hydrogen will face several challenges such as carbon dioxide emissions from the current production methods and the need for infrastructure modification for transport and safety. Researchers indicated the viability of hydrogen in decarbonizing heat while some studies also challenged its long-term role in the future of heating. In this paper a comprehensive literature review is carried out by identifying the following key aspects which could impact the conclusion on the overall role of hydrogen in heat decarbonization: (i) a holistic view of the energy system considering factors such as renewable integration and system balancing; (ii) consumer-oriented approaches often overlook the broader benefits of hydrogen in emission reduction and grid stability; (iii) carbon capture and storage scalability is a key factor for large-scale production of low-emission blue hydrogen; (iv) technological improvements could increase the cost-effectiveness of hydrogen; (v) the role of hydrogen in enhancing resilience especially during extreme weather conditions raises the potential of hydrogen as a flexible asset in the energy infrastructure for future energy supply; and finally when considering the UK as a basis case (vi) incorporating factors such as the extensive gas network and unique climate conditions necessitates specific strategies.
Numerical Study on Hydrogen–Gasoline Dual-Fuel Spark Ignition Engine
Nov 2022
Publication
Hydrogen as a suitable and clean energy carrier has been long considered a primary fuel or in combination with other conventional fuels such as gasoline and diesel. Since the density of hydrogen is very low in port fuel-injection configuration the engine’s volumetric efficiency reduces due to the replacement of hydrogen by intake air. Therefore hydrogen direct in-cylinder injection (injection after the intake valve closes) can be a suitable solution for hydrogen utilization in spark ignition (SI) engines. In this study the effects of hydrogen direct injection with different hydrogen energy shares (HES) on the performance and emissions characteristics of a gasoline port-injection SI engine are investigated based on reactive computational fluid dynamics. Three different injection timings of hydrogen together with five different HES are applied at low and full load on a hydrogen– gasoline dual-fuel SI engine. The results show that retarded hydrogen injection timing increases the concentration of hydrogen near the spark plug resulting in areas with higher average temperatures which led to NOX emission deterioration at −120 Crank angle degree After Top Dead Center (CAD aTDC) start of injection (SOI) compared to the other modes. At −120 CAD aTDC SOI for 50% HES the amount of NOX was 26% higher than −140 CAD aTDC SOI. In the meanwhile an advanced hydrogen injection timing formed a homogeneous mixture of hydrogen which decreased the HC and soot concentration so that −140 CAD aTDC SOI implied the lowest amount of HC and soot. Moreover with the increase in the amount of HES the concentrations of CO CO2 and soot were reduced. Having the HES by 50% at −140 CAD aTDC SOI the concentrations of particulate matter (PM) CO and CO2 were reduced by 96.3% 90% and 46% respectively. However due to more complete combustion and an elevated combustion average temperature the amount of NOX emission increased drastically.
Socio-economic Aspects of Hydrogen Energy: An Integrative Review
Apr 2023
Publication
Hydrogen can be recognized as the most plausible fuel for promoting a green environment. Worldwide developed and developing countries have established their hydrogen research investment and policy frameworks. This analysis of 610 peer-reviewed journal articles from the last 50 years provides quantitative and impartial insight into the hydrogen economy. By 2030 academics and business professionals believe that hydrogen will complement other renewable energy (RE) sources in the energy revolution. This study conducts an integrative review by employing software such as Bibliometrix R-tool and VOSviewer on socio-economic consequences of hydrogen energy literature derived from the Scopus database. We observed that most research focuses on multidisciplinary concerns such as generation storage transportation application feasibility and policy development. We also present the conceptual framework derived from in-depth literature analysis as well as the interlinkage of concepts themes and aggregate dimensions to highlight research hotspots and emerging patterns. In the future factors such as green hydrogen generation hydrogen permeation and leakage management efficient storage risk assessment studies blending and techno-economic feasibility shall play a critical role in the socio-economic aspects of hydrogen energy research.
Thermodynamic Performance and Creep Life Assessment Comparing Hydrogen- and Jet-Fueled Turbofan Aero Engine
Apr 2021
Publication
There is renewed interest in hydrogen as an alternative fuel for aero engines due to their perceived environmental and performance benefits compared to jet fuel. This paper presents a cycle thermal performance energy and creep life assessment of hydrogen compared with jet fuel using a turbofan aero engine. The turbofan cycle performance was simulated using a code developed by the authors that allows hydrogen and jet fuel to be selected as fuel input. The exergy assessment uses both conservations of energy and mass and the second law of thermodynamics to understand the impact of the fuels on the exergy destruction exergy efficiency waste factor ratio environmental effect factor and sustainability index for a turbofan aero engine. Finally the study looks at a top-level creep life assessment on the high-pressure turbine hot section influenced by the fuel heating values. This study shows performance (64% reduced fuel flow rate better SFC) and more extended blade life (15% increase) benefits using liquefied hydrogen fuel which corresponds with other literary work on the benefits of LH2 over jet fuel. This paper also highlights some drawbacks of hydrogen fuel based on previous research work and gives recommendations for future work aimed at maturing the hydrogen fuel concept in aviation.
Comparative Sustainability Study of Energy Storage Technologies Using Data Envelopment Analysis
Mar 2022
Publication
The transition to energy systems with a high share of renewable energy depends on the availability of technologies that can connect the physical distances or bridge the time differences between the energy supply and demand points. This study focuses on energy storage technologies due to their expected role in liberating the energy sector from fossil fuels and facilitating the penetration of intermittent renewable sources. The performance of 27 energy storage alternatives is compared considering sustainability aspects by means of data envelopment analysis. To this end storage alternatives are first classified into two clusters: fast-response and long-term. The levelized cost of energy energy and water consumption global warming potential and employment are common indicators considered for both clusters while energy density is used only for fast-response technologies where it plays a key role in technology selection. Flywheel reveals the highest efficiency between all the fast-response technologies while green ammonia powered with solar energy ranks first for long-term energy storage. An uncertainty analysis is incorporated to discuss the reliability of the results. Overall results obtained and guidelines provided can be helpful for both decision-making and research and development purposes. For the former we identify the most appealing energy storage options to be promoted while for the latter we report quantitative improvement targets that would make inefficient technologies competitive if attained. This contribution paves the way for more comprehensive studies in the context of energy storage by presenting a powerful framework for comparing options according to multiple sustainability indicators.
A Study into Proton Exchange Membrane Fuel Cell Power and Voltage Prediction using Artificial Neural Network
Sep 2022
Publication
Polymer Electrolyte Membrane fuel cell (PEMFC) uses hydrogen as fuel to generate electricity and by-product water at relatively low operating temperatures which is environmentally friendly. Since PEMFC performance characteristics are inherently nonlinear and related predicting the best performance for the different operating conditions is essential to improve the system’s efficiency. Thus modeling using artificial neural networks (ANN) to predict its performance can significantly improve the capabilities of handling multi-variable nonlinear performance of the PEMFC. This paper predicts the electrical performance of a PEMFC stack under various operating conditions. The four input terms for the 5 W PEMFC include anode and cathode pressures and flow rates. The model performances are based on ANN using two different learning algorithms to estimate the stack voltage and power. The models have shown consistently to be comparable to the experimental data. All models with at least five hidden neurons have coefficients of determination of 0.95 or higher. Meanwhile the PEMFC voltage and power models have mean squared errors of less than 1 × 10−3 V and 1 × 10−3 W respectively. Therefore the model results demonstrate the potential use of ANN into the implementation of such models to predict the steady state behavior of the PEMFC system (not limited to polarization curves) for different operating conditions and help in the optimization process for achieving the best performance of the system.
Expert Perceptions of Game-changing Innovations towards Net Zero
Dec 2022
Publication
Current technological improvements are yet to put the world on track to net-zero which will require the uptake of transformative low-carbon innovations to supplement mitigation efforts. However the role of such innovations is not yet fully understood; some of these ‘miracles’ are considered indispensable to Paris Agreement-compliant mitigation but their limitations availability and potential remain a source of debate. We evaluate such potentially game-changing innovations from the experts’ perspective aiming to support the design of realistic decarbonisation scenarios and better-informed net-zero policy strategies. In a worldwide survey 260 climate and energy experts assessed transformative innovations against their mitigation potential at-scale availability and/or widescale adoption and risk of delayed diffusion. Hierarchical clustering and multi-criteria decision-making revealed differences in perceptions of core technological innovations with next generation energy storage alternative building materials iron-ore electrolysis and hydrogen in steelmaking emerging as top priorities. Instead technologies highly represented in well-below-2◦C scenarios seemingly feature considerable and impactful delays hinting at the need to re-evaluate their role in future pathways. Experts’ assessments appear to converge more on the potential role of other disruptive innovations including lifestyle shifts and alternative economic models indicating the importance of scenarios including non-technological and demand-side innovations. To provide insights for expert elicitation processes we finally note caveats related to the level of representativeness among the 260 engaged experts the level of their expertise that may have varied across the examined innovations and the potential for subjective interpretation to which the employed linguistic scales may be prone to.
Assessing Damaged Pipelines Transporting Hydrogen
Jun 2022
Publication
There is worldwide interest in transporting hydrogen using both new pipelines and pipelines converted from natural gas service. Laboratory tests investigating the effect of hydrogen on the mechanical properties of pipeline steels have shown that even low partial pressures of hydrogen can substantially reduce properties such as reduction in area and fracture toughness and increase fatigue crack growth rates. However qualitative arguments suggest that the effects on pipelines may not be as severe as predicted from the small scale tests. If the trends seen in laboratory tests do occur in service there are implications for the assessment of damage such as volumetric corrosion dents and mechanical interference. Most pipeline damage assessment methods are semi-empirical and have been calibrated with data from full scale tests that did not involve hydrogen. Hence the European Pipeline Research Group (EPRG) commissioned a study to investigate damage assessment methods in the presence of hydrogen. Two example pipeline designs were considered both were assessed assuming a modern high performance material and an older material. From these analyses the numerical results show that the high toughness material will tolerate damage even if the properties are degraded by hydrogen exposure. However low toughness materials may not be able to tolerate some types of severe damage. If the predictions are realistic operators may have to repair more damage or reduce operating pressures. Furthermore damage involving cracking may not Page 2 of 22 satisfy the ASME B31.12 requirements for preventing time dependent crack growth. Further work is required to determine if the effects predicted using small scale laboratory test data will occur in practice.
Effect of Heat Transfer through the Release of Pipe on Simulations of Cryogenic Hydrogen Jet Fires and Hazard Distances
Sep 2021
Publication
Jet flames originated by cryo-compressed ignited hydrogen releases can cause life-threatening conditions in their surroundings. Validated models are needed to accurately predict thermal hazards from a jet fire. Numerical simulations of cryogenic hydrogen flow in the release pipe are performed to assess the effect of heat transfer through the pipe walls on jet parameters. Notional nozzle exit diameter is calculated based on the simulated real nozzle parameters and used in CFD simulations as a boundary condition to model jet fires. The CFD model was previously validated against experiments with vertical cryogenic hydrogen jet fires with release pressures up to 0.5 MPa (abs) release diameter 1.25 mm and temperatures as low as 50 K. This study validates the CFD model in a wider domain of experimental release conditions - horizontal cryogenic jets at exhaust pipe temperature 80 K pressure up to 2 MPa abs and release diameters up to 4 mm. Simulation results are compared against experimentally measured parameters as hydrogen mass flow rate flame length and radiative heat flux at several locations from the jet fire. The CFD model reproduces well experiments with reasonable engineering accuracy. Jet fire hazard distances established using three different criteria - temperature thermal radiation and thermal dose - are compared and discussed based on CFD simulation results.
Present and Projected Developments in Hydrogen Production: A Technological Review
Mar 2022
Publication
Energy supplies that are safe environmentally friendly dependable and cost-effective are important for society's long-term growth and improved living standards though political social and economic barriers may inhibit their availability. Constantly increasing energy demand is induced by substantial population growth and economic development putting an increasing strain on fossil fuel management and sustainability which account for a major portion of this rising energy demand and moreover creates difficulties because of greenhouse gas emissions growth and the depletion of resources. Such impediments necessitate a global shift away from traditional energy sources and toward renewables. Aside from its traditional role is viewed as a promising energy vector and is gaining international attention as a promising fuel path as it provides numerous benefits in use case scenarios and unlike other synthesized carbon-based fuels could be carbon-free or perhaps even negative on a life-cycle criterion. Hydrogen ( ) is one of the most significant chemical substances on earth and can be obtained as molecular dihydrogen through various techniques from both non-renewable and renewable sources. The drive of this paper is to deliver a technological overview of hydrogen production methods. The major challenges development and research priorities and potential prospects for production was discussed.
Current and Future role of Haber–Bosch Ammonia in a Carbon-free Energy Landscape
Dec 2019
Publication
The future of a carbon-free society relies on the alignment of the intermittent production of renewable energy with our continuous and increasing energy demands. Long-term energy storage in molecules with high energy content and density such as ammonia can act as a buffer versus short-term storage (e.g. batteries). In this paper we demonstrate that the Haber–Bosch ammonia synthesis loop can indeed enable a second ammonia revolution as energy vector by replacing the CO2 intensive methane-fed process with hydrogen produced by water splitting using renewable electricity. These modifications demand a redefinition of the conventional Haber–Bosch process with a new optimisation beyond the current one which was driven by cheap and abundant natural gas and relaxed environmental concerns during the last century. Indeed the switch to electrical energy as fuel and feedstock to replace fossil fuels (e.g. methane) will lead to dramatic energy efficiency improvements through the use of high efficiency electrical motors and complete elimination of direct CO2 emissions. Despite the technical feasibility of the electrically-driven Haber–Bosch ammonia the question still remains whether such revolution will take place. We reveal that its success relies on two factors: increased energy efficiency and the development of small-scale distributed and agile processes that can align to the geographically isolated and intermittent renewable energy sources. The former requires not only higher electrolyser efficiencies for hydrogen production but also a holistic approach to the ammonia synthesis loop with the replacement of the condensation separation step by alternative technologies such as absorption and catalysis development. Such innovations will open the door to moderate pressure systems the development and deployment of novel ammonia synthesis catalysts and even more importantly the opportunity for integration of reaction and separation steps to overcome equilibrium limitations. When realised green ammonia will reshape the current energy landscape by directly replacing fossil fuels in transportation heating electricity etc. and as done in the last century food.
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