United Kingdom
Economic Performance Evaluation of Flexible Centralised and Decentralised Blue Hydrogen Production Systems Design Under Uncertainty
Sep 2023
Publication
Blue hydrogen is viewed as an important energy vector in a decarbonised global economy but its large-scale and capital-intensive production displays economic performance vulnerabities in the face of increased market and regulatory uncertainty. This study analyses flexible (modular) blue hydrogen production plant designs and evaluates their effectiveness to enhance economic performance under uncertainty. The novelty of this work lies in the development of a comprehensive techno-economic evaluation framework that considers flexible centralised and decentralised blue hydrogen plant design alternatives in the presence of irreducible uncertainty whilst explicitly considering the time value of money economies of scale and learning effects. A case study of centralised and decentralised blue hydrogen production for the transport sector in the San Francisco area is developed to highlight the underlying value of flexibility. The proposed methodological framework considers various blue hydrogen plant designs (fixed phased and flexible) and compares them using relevant economic indicators (net present value (NPV) capex value-at-risk/gain etc.) through a detailed Monte Carlo simulation framework. Results indicate that flexible centralised hydrogen production yields greater economic value than alternative designs despite the associated cost-premium of modularity. It is also shown that the value of flexibility increases under greater uncertainty higher learning rates and weaker economies of scale. Moreover sensitivity analysis reveals that flexible design remains the preferred investment option over a wide range of market and regulatory conditions except for high initial hydrogen demand. Finally this study demonstrates that major regulatory and market uncertainties surrounding blue hydrogen production can be effectively managed through the application of flexible engineering system design that protects the investment from major downside risks whilst allowing access to favourable upside opportunities.
Green Hydrogen Production and Liquefaction Using Offshore Wind Power, Liquid Air, and LNG Cold Energy
Sep 2023
Publication
Coastal regions have abundant off-shore wind energy resources and surrounding areas have large-scale liquefied natural gas (LNG) receiving stations. From the engineering perspectives there are limitations in unstable off-shore wind energy and fluctuating LNG loads. This article offers a new energy scheme to combine these 2 energy units which uses surplus wind energy to produce hydrogen and use LNG cold energy to liquefy and store hydrogen. In addition in order to improve the efficiency of utilizing LNG cold energy and reduce electricity consumption for liquid hydrogen (LH2) production at coastal regions this article introduces the liquid air energy storage (LAES) technology as the intermediate stage which can stably store the cold energy from LNG gasification. A new scheme for LNG-LAES-LH2 hybrid LH2 production is built. The case study is based on a real LNG receiving station at Hainan province China and this article presents the design of hydrogen production/liquefaction process and carries out the optimizations at key nodes and proves the feasibility using specific energy consumption and exergy analysis. In a 100 MW system the liquid air storage round-trip efficiency is 71.0% and the specific energy consumption is 0.189 kWh/kg and the liquid hydrogen specific energy consumption is 7.87 kWh/kg and the exergy efficiency is 46.44%. Meanwhile the corresponding techno-economic model is built and for a LNGLAES-LH2 system with LH2 daily production 140.4 tons the shortest dynamic payback period is 9.56 years. Overall this novel hybrid energy scheme can produce green hydrogen using a more efficient and economical method and also can make full use of surplus off-shore wind energy and coastal LNG cold energy.
Exergy Analysis in Intensification of Sorption-enhanced Steam Methane Reforming for Clean Hydrogen Production: Comparative Study and Efficiency Optimisation
Feb 2024
Publication
Hydrogen has a key role to play in decarbonising industry and other sectors of society. It is important to develop low-carbon hydrogen production technologies that are cost-effective and energy-efficient. Sorption-enhanced steam methane reforming (SE-SMR) is a developing low-carbon (blue) hydrogen production process which enables combined hydrogen production and carbon capture. Despite a number of key benefits the process is yet to be fully realised in terms of efficiency. In this work a sorption-enhanced steam methane reforming process has been intensified via exergy analysis. Assessing the exergy efficiency of these processes is key to ensuring the effective deployment of low-carbon hydrogen production technologies. An exergy analysis was performed on an SE-SMR process and was then subsequently used to incorporate process improvements developing a process that has theoretically an extremely high CO2 capture rate of nearly 100 % whilst simultaneously demonstrating a high exergy efficiency (77.58 %) showcasing the potential of blue hydrogen as an effective tool to ensure decarbonisation in an energy-efficient manner.
Review of the Status and Prospects of Fiber Optic Hydrogen Sensing Technology
Aug 2023
Publication
With the unprecedented development of green and renewable energy sources the proportion of clean hydrogen (H2 ) applications grows rapidly. Since H2 has physicochemical properties of being highly permeable and combustible high-performance H2 sensors to detect and monitor hydrogen concentration are essential. This review discusses a variety of fiber-optic-based H2 sensor technologies since the year 1984 including: interferometer technology fiber grating technology surface plasma resonance (SPR) technology micro lens technology evanescent field technology integrated optical waveguide technology direct transmission/reflection detection technology etc. These technologies have been evolving from simply pursuing high sensitivity and low detection limits (LDL) to focusing on multiple performance parameters to match various application demands such as: high temperature resistance fast response speed fast recovery speed large concentration range low cross sensitivity excellent long-term stability etc. On the basis of palladium (Pd)-sensitive material alloy metals catalysts or nanoparticles are proposed to improve the performance of fiberoptic-based H2 sensors including gold (Au) silver (Ag) platinum (Pt) zinc oxide (ZnO) titanium oxide (TiO2 ) tungsten oxide (WO3 ) Mg70Ti30 polydimethylsiloxane (PDMS) graphene oxide (GO) etc. Various microstructure processes of the side and end of optical fiber H2 sensors are also discussed in this review.
A Study on the Viability of Fuel Cells as an Alternative to Diesel Fuel Generators on Ships
Jul 2023
Publication
This study investigates methods for reducing air pollution in the shipping sector particularly in port areas. The study examines the use of fuel cells as an alternative to diesel generators. Environmental pollution at ports remains a critical issue so using fuel cells as an alternative to conventional energy systems warrants further research. This study compares commercial fuel cell types that can be used on a case study very large crude carrier (VLCC) vessel specifically although the technology is applicable to other vessels and requirements. Seven different fuel cell types were ranked based on five criteria to accomplish this. The proton-exchange membrane cell type was found to be the most suitable fuel cell type for the case study vessel. Based on the input fuel ammonia-based hydrogen storage has been identified as the most promising option along with using an ammonia reforming unit to produce pure hydrogen. Furthermore this study provides an integrated fuel cell module and highlights the economic environmental and maintenance aspects of implementing the proton-exchange membrane fuel cell module for this case study. It also calculates the required space as a crucial constraint of implementing fuel cell technology at sea.
Hydrogen Informed Gurson Model for Hydrogen Embrittlement Simulation
Jul 2019
Publication
Hydrogen-microvoid interactions were studied via unit cell analyses with different hydrogen concentrations. The absolute failure strain decreases with hydrogen concentration but the failure loci were found to follow the same trend dependent only on stress triaxiality in other words the effects of geometric constraint and hydrogen on failure are decoupled. Guided by the decoupling principle a hydrogen informed Gurson model is proposed. This model is the first practical hydrogen embrittlement simulation tool based on the hydrogen enhanced localized plasticity (HELP) mechanism. It introduces only one additional hydrogen related parameter into the Gurson model and is able to capture hydrogen enhanced internal necking failure of microvoids with accuracy; its parameter calibration procedure is straightforward and cost efficient for engineering purpose
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.
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.
Life Cycle Analysis of Hydrogen Powered Marine Vessels—Case Ship Comparison Study with Conventional Power System
Aug 2023
Publication
The latest International Maritime Organization strategies aim to reduce 70% of the CO2 emissions and 50% of the Greenhouse Gas (GHG) emissions from maritime activities by 2050 compared to 2008 levels. The EU has set up goals to reduce GHG emissions by at least 55% by 2030 compared to 1990 and achieve net-zero GHG emissions by 2050. The UK aims to achieve more than 68% GHG emission reduction by 2030 and net-zero GHG emissions by 2050. There are many solutions under development to tackle the challenge of meeting the latest decarbonization strategies from the IMO EU and UK among which are hydrogen powered marine vessels. This paper presents a life cycle analysis study for hydrogen fuelled vessels by evaluating their performance in terms of environmental friendliness and economic feasibility. The LCA study will consider the gas emissions and costs during the life stages of the ships including the construction operation maintenance and recycling phases of the selected vessels. The results of the comparisons with the conventional version of the ships (driven by diesel generators) demonstrate the benefits of using hydrogen for marine transportation: over 80% emission reduction and around 60% life cycle cost savings. A sensitivity analysis shows that the prices of fuels and carbon credits can affect the life cycle cost and recommendations for low H2 price and high carbon credit in the future are provided to attract the industry to adopt the new fuel.
Rethinking "BELVE Explosion" After Liquid Hydrogen Storage Tank Rupture in a Fire
Sep 2022
Publication
The underlying physical mechanisms leading to the generation of blast waves after liquid hydrogen (LH2) storage tank rupture in a fire are not yet fully understood. This makes it difficult to develop predictive models and validate them against a very limited number of experiments. This study aims at the development of a CFD model able to predict maximum pressure in the blast wave after the LH2 storage tank rupture in a fire. The performed critical review of previous works and the thorough numerical analysis of BMW experiments (LH2 storage pressure in the range 2.0e11.3 bar abs) allowed us to conclude that the maximum pressure in the blast wave is generated by gaseous phase starting shock enhanced by combustion reaction of hydrogen at the contact surface with heated by the shock air. The boiling liquid expanding vapour explosion (BLEVE) pressure peak follows the gaseous phase blast and is smaller in amplitude. The CFD model validated recently against high-pressure hydrogen storage tank rupture in fire experiments is essentially updated in this study to account for cryogenic conditions of LH2 storage. The simulation results provided insight into the blast wave and combustion dynamics demonstrating that combustion at the contact surface contributes significantly to the generated blast wave increasing the overpressure at 3 m from the tank up to 5 times. The developed CFD model can be used as a contemporary tool for hydrogen safety engineering e.g. for assessment of hazard distances from LH2 storage.
A Comprehensive Resilience Assessment Framework for Hydrogen Energy Infrastructure Development
Jun 2023
Publication
In recent years sustainable development has become a challenge for many societies due to natural or other disruptive events which have disrupted economic environmental and energy infrastructure growth. Developing hydrogen energy infrastructure is crucial for sustainable development because of its numerous benefits over conventional energy sources. However the complexity of hydrogen energy infrastructure including production utilization and storage stages requires accounting for potential vulnerabilities. Therefore resilience needs to be considered along with sustainable development. This paper proposes a decision-making framework to evaluate the resilience of hydrogen energy infrastructure by integrating resilience indicators and sustainability contributing factors. A holistic taxonomy of resilience performance is first developed followed by a qualitative resilience assessment framework using a novel Intuitionistic fuzzy Weighted Influence Nonlinear Gauge System (IFWINGS). The results highlighted that Regulation and legislation Government preparation and Crisis response budget are the most critical resilience indicators in the understudy hydrogen energy infrastructure. A comparative case study demonstrates the practicality capability and effectiveness of the proposed approach. The results suggest that the proposed model can be used for resilience assessment in other areas.
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.
Review on Ammonia as a Potential Fuel: From Synthesis to Economics
Feb 2021
Publication
Ammonia a molecule that is gaining more interest as a fueling vector has been considered as a candidate to power transport produce energy and support heating applications for decades. However the particular characteristics of the molecule always made it a chemical with low if any benefit once compared to conventional fossil fuels. Still the current need to decarbonize our economy makes the search of new methods crucial to use chemicals such as ammonia that can be produced and employed without incurring in the emission of carbon oxides. Therefore current efforts in this field are leading scientists industries and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector moving through all of the steps in the production distribution utilization safety legal considerations and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes legal barriers that will be faced to achieve its deployment safety and environmental considerations that impose a critical aspect for acceptance and wellbeing and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein this work sets the principles research practicalities and future views of a transition toward a future where ammonia will be a major energy player.
Techno-economic Analysis to Identify the Optimal Conditions for Green Hydrogen Production
Jun 2023
Publication
The intermittency of renewable energy sources necessitates energy storage to meet the full demand and balancing requirements of the grid. Green hydrogen (H2) is a chemical energy carrier that can be used in a flexible manner and store large amounts of energy for long periods of time. This techno-economic analysis investigates H2 production from wind using commercially available desalination and electrolysis units. Proton exchange membrane and alkaline electrolyser units are utilised and compared. The intermittency of wind is examined with comparison against grid-bought electricity. A model is developed to determine the selling price required to ensure profitability over a 10-year period. Firstly where H2 is produced using energy from the grid with electricity purchased when below a specified price point or between specified hours. In the second scenario a wind turbine is owned by the user and the electricity price is not considered while the turbine capital expenditure is. The price of H2 production from wind is found to be comparable with natural gas derived H2 at a larger scale with a minimum selling price calculated to be 4.85 £/kg at a setpoint of 500 kg of H2/hr. At a setpoint of 50 kg of H2/hr this is significantly higher at 12.10 £/kg. In both cases the alkaline electrolyser produced cheaper H2. This study demonstrates an economy of scale with H2 prices decreasing with increased scale. H2 prices are also closely linked to the capital expenditure with the equipment size space and safety identified as limiting factors.
An Integrated Framework for Optimal Infrastructure Planning for Decarbonising Heating
Apr 2023
Publication
This paper presents the HEGIT (Heat Electricity and Gas Infrastructure and Technology) model for optimal infrastructure planning for decarbonising heating in buildings. HEGIT is an optimisation model based on Mixed Integer Linear Programming. The model co-optimises the integrated operation and capacity expansion planning of electricity and gas grids as well as heating technologies on the consumer side while maintaining the security of supply and subject to different environmental operational and system-wide constraints. The three main features of the HEGIT model are: • It incorporates an integrated unit commitment and capacity expansion problem for coordinated operation and long-term investment planning of the electricity and gas grids. • It incorporates the flexible operation of heating technologies in buildings and demand response in operation and long-term investment planning of gas and electricity grids. • It incorporates a multi-scale techno-economic representation of heating technologies design features into the whole energy system modelling and capacity planning. These features enable the model to quantify the impacts of different policies regarding decarbonising heating in buildings on the operation and long-term planning of electricity and gas grids identify the cost-optimal use of available resources and technologies and identify strategies for maximising synergies between system planning goals and minimising trade-offs. Moreover the multi-scale feature of the model allows for multi-scale system engineering analysis of decarbonising heating including system-informed heating technology design identifying optimal operational setups at the consumer end and assessing trade-offs between consumer investment in heating technologies and infrastructure requirements in different heat decarbonisation pathways.
Wind Farm Control for Improved Battery Lifetime in Green Hydrogen Systems without a Grid Connection
Jul 2023
Publication
Green hydrogen is likely to play an important role in meeting the net-zero targets of countries around the globe. One potential option for green hydrogen production is to run electrolysers directly from offshore wind turbines with no grid connection and hence no expensive cabling to shore. In this work an innovative proof of concept of a wind farm control methodology designed to reduce variability in wind farm active power output is presented. Smoothing the power supplied by the wind farm to the battery reduces the size and number of battery charge cycles and helps to increase battery lifetime. This work quantifies the impact of the wind farm control method on battery lifetime for wind farms of 1 4 9 and 16 wind turbines using suitable wind farm battery and electrolyser models. The work presented shows that wind farm control for smoothing wind farm power output could play a critical role in reducing the levelised cost of green hydrogen produced from wind farms with no grid connection by reducing the damaging load cycles on batteries in the system. Hence this work paves the way for the design and testing of a full implementation of the wind farm controller.
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.
Perspectives and Prospects of Underground Hydrogen Storage and Natural Hydrogen
Jun 2022
Publication
Hydrogen is considered the fuel of the future due to its cleaner nature compared to methane and gasoline. Therefore renewable hydrogen production technologies and long-term affordable and safe storage have recently attracted significant research interest. However natural underground hydrogen production and storage have received scant attention in the literature despite its great potential. As such the associated formation mechanisms geological locations and future applications remain relatively under-explored thereby requiring further investigation. In this review the global natural hydrogen formation along with reaction mechanisms (i.e. metamorphic processes pyritization and serpentinization reactions) as well as the suitable geological locations (i.e. ophiolites organic-rich sediments fault zones igneous rocks crystalline basements salt bearing strata and hydrocarbon-bearing basins) are discussed. Moreover the underground hydrogen storage mechanisms are detailed and compared with underground natural gas and CO2 storage. Techno-economic analyses of large-scale underground hydrogen storage are presented along with the current challenges and future directions.
Navigating Turbulence: Hydrogen's Role in the Decarbonization of the Aviation Sector
Jan 2024
Publication
This paper offers a comprehensive analysis of the historical evolution and the current state of the aviation industry with a particular emphasis on the critical need for this sector to decarbonize. It delves into emerging propulsion technologies such as battery electric and hydrogen-based systems assessing their potential impact on sustainability within the aviation sector. Special attention is devoted to the global regulatory framework notably carbon offsetting and emission reduction scheme for international aviation which encapsulates initiatives such as lower carbon aviation fuels and sustainable aviation fuels. Examining the environmental challenges facing aviation the paper underscores the necessity for a balanced and comprehensive strategy that integrates various approaches to achieve sustainable solutions. By addressing both the historical context and contemporary advances the paper aims to provide a nuanced understanding of the complexities surrounding aviation's decarbonization journey acknowledging the industry's strides while recognizing the ongoing challenges in the pursuit of sustainability.
Policy Design for Diffusing Hydrogen Economy and Its Impact on the Japanese Economy for Carbon Neutrality by 2050: Analysis Using the E3ME-FTT Model
Nov 2023
Publication
To achieve carbon neutrality in Japan by 2050 renewable energy needs to be used as the main energy source. Based on the constraints of various renewable energies the importance of hydrogen cannot be ignored. This study aimed to investigate the diffusion of hydrogen demand technologies in various sectors and used projections and assumptions to investigate the hydrogen supply side. By performing simulations with the E3ME-FTT model and comparing various policy scenarios with the reference scenario the economic and environmental impacts of the policy scenarios for hydrogen diffusion were analyzed. Moreover the impact of realizing carbon neutrality by 2050 on the Japanese economy was evaluated. Our results revealed that large-scale decarbonization via hydrogen diffusion is possible (90% decrease of CO2 emissions in 2050 compared to the reference) without the loss of economic activity. Additionally investments in new hydrogen-based and other low-carbon technologies in the power sector freight road transport and iron and steel industry can improve the gross domestic product (1.6% increase in 2050 compared to the reference) as they invoke economic activity and require additional employment (0.6% increase in 2050 compared to the reference). Most of the employment gains are related to decarbonizing the power sector and scaling up the hydrogen supply sector while a lot of job losses can be expected in the mining and fossil fuel industries.
Premier, Progress and Prospects in Renewable Hydrogen Generation: A Review
May 2023
Publication
Renewable hydrogen production has an opportunity to reduce carbon emissions in the transportation and industrial sectors. This method generates hydrogen utilizing renewable energy sources such as the sun wind and hydropower lowering the number of greenhouse gases released into the environment. In recent years considerable progress has been made in the production of sustainable hydrogen particularly in the disciplines of electrolysis biomass gasification and photoelectrochemical water splitting. This review article figures out the capacity efficiency and cost-effectiveness of hydrogen production from renewable sources effectively comparing the conventionally used technologies with the latest techniques which are getting better day by day with the implementation of the technological advancements. Governments investors and industry players are increasingly interested in manufacturing renewable hydrogen and the global need for clean energy is expanding. It is projected that facilities for manufacturing renewable hydrogen as well as infrastructure to support this development would expand hastening the transition to an environment-friendly and low-carbon economy
Assessment of Hydrogen Gas Turbine-fuel Cell Powerplant for Rotorcraft
Jul 2023
Publication
Conventional turboshaft engines are high power density movers suffering from low efficiency at part power operation and producing significant emissions. This paper presents a design exploration and feasibility assessment of a hybrid hydrogen-fueled powerplant for Urban Air Mobility (UAM) rotorcraft. A multi-disciplinary approach is devised comprising models for rotorcraft performance tank and subsystems sizing and engine performance. The respective trade-offs between payload-range and mission level performance are quantified for kerosene-fueled and hybrid hydrogen tilt-rotor variants. The effects of gas turbine scaling and fuel cell pressurization are evaluated for different hybridization degrees. Gas turbine scaling with hybridization (towards the fuel cell) results in up to 21% benefit in energy consumption relative to the non-scaled case with the benefits being more pronounced at high hybridization degrees. Pressurizing the fuel cell has shown significant potential as cell efficiency can increase up to 10% when pressurized to 6 bar which translates to a 6% increase in overall efficiency. The results indicate that current fuel cells (1 kW/kg) combined with current hydrogen tank technology severely limit the payload range capability of the tilt-rotor. However for advanced fuel cell technology (2.5 kW/kg) and low ranges hybrid powerplant show the potential to reduce energy consumption and reduce emissions footprint.
HyDeploy2 Project: Winlaton Trial Report
Sep 2022
Publication
The HyDeploy project seeks to address a key issue for UK customers and UK energy policy makers: how to reduce the carbon emitted from heating homes. The UK has a world class gas distribution grid delivering heat conveniently and safely to over 83% of homes. Emissions can be reduced by lowering the carbon content of gas through blending with hydrogen. This delivers carbon savings without customers requiring disruptive and expensive changes in their homes. It also provides the platform for deeper carbon savings by enabling wider adoption of hydrogen across the energy system. HyDeploy has previously delivered a successful trial demonstrations of repurposing existing UK distribution gas networks (Keele University) to operate on a blend of natural gas and hydrogen (up to 20% mol/mol) showing that carbon savings can be made through the gas networks today whilst continuing to meet the needs of gas consumers without introducing any disruptions.<br/>The ultimate objective of the HyDeploy programme is to see the roll-out of hydrogen blends across the GB gas distribution network unlocking 35 TWh pa of low carbon heat - the equivalent of removing 2.5 million fossil-fuelled cars off the roads. To achieve this the next phase of the programme is to address the remaining evidence gaps that had not been covered by the trial demonstration programmes.<br/>The demonstrations have focussed on the low and medium pressure tiers of the gas distribution network (i.e. injecting into a 2 bar gauge pressure network and distributing the blended gas down to the low pressure network and into people’s homes and commercial buildings and businesses) and predominantly serving domestic appliances.<br/>The remainder of the HyDeploy2 programme will generate an evidence base for GB’s gas distribution network which includes demonstrating the suitability of using hydrogen blended gas in the fields of industrial and commercial users and the performance of materials assets and procedures on the higher pressure tiers (i.e. 7 bar gauge operation and above).<br/>This report captures the details of the Winlaton trial and provides a future look to how the UK can transition from successful hydrogen blending trials to roll-out.
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.
Performance and Failure Analysis of a Retrofitted Cessna Aircraft with a Fuel Cell Power System Fuelled with Liquid Hydrogen
Jan 2022
Publication
Proton-Exchange Membrane-Fuel Cells (PEM-FC) are regarded as one of the prime candidates to provide emissions-free electricity for propulsion systems of aircraft. Here a turbocharged Fuel Cell Power System (FCPS) powered with liquid H2 (LH2) is designed and modelled to provide a primary power source in retrofitted Cessna 208 Caravan aircraft. The proposed FCPS comprises multiple PEM-FCs assembled in stacks two single-stage turbochargers to mitigate the variation of the ambient pressure with altitude two preheaters two humidifiers and two combustors. Interlinked component sub-models are constructed in MATLAB and referenced to commercially available equipment. The FCPS model is used to simulate steady-state responses in a proposed 1.5 h (∼350 km) mission flight determining the overall efficiency of the FCPS at 43% and hydrogen consumption of ∼28 kg/h. The multi-stack FCPS is modelled applying parallel fluidic and electrical architectures analysing two power-sharing methods: equally distributed and daisy-chaining. The designed LH2-FCPS is then proposed as a power system to a retrofitted Cessna 208 Caravan and with this example analysed for the probability of failure occurrence. The results demonstrate that the proposed “dual redundant” FCPS can reach failure rates comparable to commercial jet engines with a rate below 1.6 failures per million hours.
Hydrogen Refuelling Station Calibration with a Traceable Gravimetric Standard
Apr 2020
Publication
Of all the alternatives to hydrocarbon fuels hydrogen offers the greatest long-term potential to radically reduce the many problems inherent in fuel used for transportation. Hydrogen vehicles have zero tailpipe emissions and are very efficient. If the hydrogen is made from renewable sources such as nuclear power or fossil sources with carbon emissions captured and sequestered hydrogen use on a global scale would produce almost zero greenhouse gas emissions and greatly reduce air pollutant emissions. The aim of this work is to realise a traceability chain for hydrogen flow metering in the range typical for fuelling applications in a wide pressure range with pressures up to 875 bar (for Hydrogen Refuelling Station - HRS with Nominal Working Pressure of 700 bar) and temperature changes from −40 °C (pre-cooling) to 85 °C (maximum allowed vehicle tank temperature) in accordance with the worldwide accepted standard SAE J2601. Several HRS have been tested in Europe (France Netherlands and Germany) and the results show a good repeatability for all tests. This demonstrates that the testing equipment works well in real conditions. Depending on the installation configuration some systematic errors have been detected and explained. Errors observed for Configuration 1 stations can be explained by pressure differences at the beginning and end of fueling in the piping between the Coriolis Flow Meter (CFM) and the dispenser: the longer the distance the bigger the errors. For Configuration 2 where this distance is very short the error is negligible.
Additive Manufacturing for Proton Exchange Membrane (PEM) Hydrogen Technologies: Merits, Challenges, and Prospects
Jul 2023
Publication
With the growing demand for green technologies hydrogen energy devices such as Proton Exchange Membrane (PEM) fuel cells and water electrolysers have received accelerated developments. However the materials and manufacturing cost of these technologies are still relatively expensive which impedes their widespread commercialization. Additive Manufacturing (AM) commonly termed 3D Printing (3DP) with its advanced capabilities could be a potential pathway to solve the fabrication challenges of PEM parts. Herein in this paper the research studies on the novel AM fabrication methods of PEM components are thoroughly reviewed and analysed. The key performance properties such as corrosion and hydrogen embrittlement resistance of the additively manufactured materials in the PEM working environment are discussed to emphasise their reliability for the PEM systems. Additionally the major challenges and required future developments of AM technologies to unlock their full potential for PEM fabrication are identified. This paper provides insights from the latest research developments on the significance of advanced manufacturing technologies in developing sustainable energy systems to address the global energy challenges and climate change effects.
The Bio Steel Cycle: 7 Steps to Net-Zero CO2 Emissions Steel Production
Nov 2022
Publication
CO2 emissions have been identified as the main driver for climate change with devastating consequences for the global natural environment. The steel industry is responsible for ~7–11% of global CO2 emissions due to high fossil-fuel and energy consumption. The onus is therefore on industry to remedy the environmental damage caused and to decarbonise production. This desk research report explores the Bio Steel Cycle (BiSC) and proposes a seven-step-strategy to overcome the emission challenges within the iron and steel industry. The true levels of combined CO2 emissions from the blast-furnace and basic-oxygen-furnace operation at 4.61 t of CO2 emissions/t of steel produced are calculated in detail. The BiSC includes CO2 capture implementing renewable energy sources (solar wind green H2 ) and plantation for CO2 absorption and provision of biomass. The 7-step-implementation-strategy starts with replacing energy sources develops over process improvement and installation of flue gas carbon capture and concludes with utilising biogas-derived hydrogen as a product from anaerobic digestion of the grown agrifood in the cycle. In the past CO2 emissions have been seemingly underreported and underestimated in the heavy industries and implementing the BiSC using the provided seven-steps-strategy will potentially result in achieving net-zero CO2 emissions in steel manufacturing by 2030.
Underground Hydrogen Storage to Balance Seasonal Variations in Energy Demand: Impact of Well Configuration on Storage Performance in Deep Saline Aquifers
Mar 2023
Publication
Grid-scale underground hydrogen storage (UHS) is essential for the decarbonization of energy supply systems on the path towards a zero-emissions future. This study presents the feasibility of UHS in an actual saline aquifer with a typical dome-shaped anticline structure to balance the potential seasonal mismatches between energy supply and demand in the UK domestic heating sector. As a main requirement for UHS in saline aquifers we investigate the role of well configuration design in enhancing storage performance in the selected site via numerical simulation. The results demonstrate that the efficiency of cyclic hydrogen recovery can reach around 70% in the short term without the need for upfront cushion gas injection. Storage capacity and deliverability increase in successive storage cycles for all scenarios with the co-production of water from the aquifer having a minimal impact on the efficiency of hydrogen recovery. Storage capacity and deliverability also increase when additional wells are added to the storage site; however the distance between wells can strongly influence this effect. For optimum well spacing in a multi-well storage scenario within a dome-shaped anticline structure it is essential to attain an efficient balance between well pressure interference effects at short well distances and the gas uprising phenomenon at large distances. Overall the findings obtained and the approach described can provide effective technical guidelines pertaining to the design and optimization of hydrogen storage operations in deep saline aquifers.
Review and Meta-analysis of Recent Life Cycle Assessments of Hydrogen Production
Apr 2023
Publication
The world is facing an urgent global climate challenge and hydrogen (H2) is increasingly valued as a carbon-free energy carrier that can play a prominent role in decarbonising economies. However the environmental impact of the different methods for hydrogen production are sometimes overlooked. This work provides a comprehensive overview of the environmental impacts and costs of a diverse range of methods for producing hydrogen. Ninety nine life cycle assessments (LCAs) of hydrogen production published between 2015 and 2022 are categorised by geography production method energy source goal and scope and compared by data sources and methodology. A meta-analysis of methodological choices is used to identify a subset of mutually comparable studies whose results are then compared initially by global warming potential (GWP) then low-GWP scenarios are compared by other indicators. The results show that the lowest GWP is achieved by methods that are currently more expensive (~US $4–9/kg H2) compared to the dominant methods of producing hydrogen from fossil fuels (~US $1–2/kg H2). The research finds that data are currently limited for comparing environmental indicators other than GWP such as terrestrial acidification or freshwater eutrophication. Recommendations are made for future LCAs of hydrogen production.
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.
Recent Advances in Sustainable and Safe Marine Engine Operation with Alternative Fuels
Nov 2022
Publication
Pursuing net-zero emission operations in the shipping industry are quintessential for this sector to mitigate the environmental impact caused by hydrocarbon fuel combustion. Significant contributions to this are expected from the substitution of conventional marine fuels by alternative emission-free fuels with lower emission footprints. This study aims to conduct a comprehensive literature review for delineating the main characteristics of the considered alternative fuels specifically focusing on hydrogen methanol and ammonia which have recently attracted attention from both industry and academia. This study comparatively assesses the potential of using these fuels in marine engines and their subsequent performance characteristics as well as the associated environmental benefits. In addition the required storage conditions space as well as the associated costs are reviewed. Special attention is given to the safety characteristics and requirements for each alternative fuel. The results of this study demonstrate that the environmental benefits gained from alternative fuel use are pronounced only when renewable energy is considerably exploited for their production whereas the feasibility of each fuel depends on the vessel type used and pertinent storage constraints. Hydrogen ammonia and methanol are considered best-fit solutions for small scale shipping requiring minimal on-board storage. In addition the need for comparative assessments between diesel and alternative fuels is highlighted and sheds light on marine engines’ operational characteristics. Moreover using combinations of alternative and diesel fuels is identified as a direction towards decarbonisation of the maritime sector; intensifying the need for optimisation studies on marine engine design and operation. This study concludes with recommendations for future research directions thus contributing to fuel research concepts that can facilitate the shipboard use of alternative fuels.
Battery and Hydrogen Energy Storage Control in a Smart Energy Network with Flexible Energy Demand Using Deep Reinforcement Learning
Sep 2023
Publication
Smart energy networks provide an effective means to accommodate high penetrations of variable renewable energy sources like solar and wind which are key for the deep decarbonisation of energy production. However given the variability of the renewables as well as the energy demand it is imperative to develop effective control and energy storage schemes to manage the variable energy generation and achieve desired system economics and environmental goals. In this paper we introduce a hybrid energy storage system composed of battery and hydrogen energy storage to handle the uncertainties related to electricity prices renewable energy production and consumption. We aim to improve renewable energy utilisation and minimise energy costs and carbon emissions while ensuring energy reliability and stability within the network. To achieve this we propose a multi-agent deep deterministic policy gradient approach which is a deep reinforcement learning-based control strategy to optimise the scheduling of the hybrid energy storage system and energy demand in real time. The proposed approach is model-free and does not require explicit knowledge and rigorous mathematical models of the smart energy network environment. Simulation results based on real-world data show that (i) integration and optimised operation of the hybrid energy storage system and energy demand reduce carbon emissions by 78.69% improve cost savings by 23.5% and improve renewable energy utilisation by over 13.2% compared to other baseline models; and (ii) the proposed algorithm outperforms the state-of-the-art self-learning algorithms like the deep-Q network.
The EU Hydrogen and Gas Decarbonisation Package: Help or Hindrance for the Development of a European Hydrogen Market?
Mar 2023
Publication
The European Commission has identified hydrogen as a key part of its decarbonisation strategy. The 2022 REPowerEU Strategy set a target of 20MT consumption of renewable hydrogen by 2030. The Commission is keen to promote a single European market in hydrogen similar to the current one for natural gas. To this end it has published proposals on the regulation of future European hydrogen infrastructure (pipelines storage facilities and import terminals). The European Council (representing Member States) and the European Parliament are finalising their amendments to the Commission proposals prior to ’trilogue’ negotiations and final agreement later this year. The paper ‘The EU Hydrogen and Gas Decarbonisation Package: help or hindrance for the development of a European hydrogen market?’ examines the European Commission proposals and their suitability for a developing hydrogen market.
Assessing the Pressure Losses during Hydrogen Transport in the Current Natural Gas Infrastructure Using Numerical Modelling
May 2023
Publication
The UK government aims to transition its modern natural gas infrastructure towards Hydrogen by 2035. Since hydrogen is a much lighter gas than methane it is important to understand the change in parameters when transporting it. While most modern work in this topic looks at the transport of hydrogen-methane mixtures this work focuses on pure hydrogen transport. The aim of this paper is to highlight the change in gas distribution parameters when natural gas is replaced by hydrogen in the existing infrastructure. This study uses analytical models and computational models to compare the flow of hydrogen and methane in a pipe based on pressure loss. The Darcy-Weisbach and Colebrook-White equations were used for the analytical models and the k- ε model was used for the computational approach. The variables considered in the comparison were the pipe material (X52 Steel and MDPE) and pipe diameters (0.01m–1m). It was observed that hydrogen had to be transported 250–270% the velocity of methane to replicate flow for a fixed length of pipe. Furthermore it was noted that MDPE pipes has 2–31% lower pressure losses compared to X52 steel for all diameters when transporting hydrogen at a high velocity. Lastly it was noted that the analytical model and computational model were in agreement with 1–5% error in their findings.
Future Energy Scenarios 2019
Jul 2019
Publication
Decarbonising energy is fundamental in the transition towards a sustainable future. Our Future Energy Scenarios aim to stimulate debate to inform the decisions that will help move us towards achieving carbon reduction targets and ultimately shape the energy system of the future.
The Prospects of Hydrogen in Achieving Net Zero Emissions by 2050: A Critical Review
May 2023
Publication
Hydrogen (H2) usage was 90 metric tonnes (Mt) in 2020 almost entirely for industrial and refining uses and generated almost completely from fossil fuels leading to nearly 900 Mt of carbon dioxide emissions. However there has been significant growth of H2 in recent years. Electrolysers' total capacity which are required to generate H2 from electricity has multiplied in the past years reaching more than 300 MW through 2021. Approximately 350 projects reportedly under construction could push total capacity to 54 GW by the year 2030. Some other 40 projects totalling output of more than 35 GW are in the planning phase. If each of these projects is completed global H2 production from electrolysers could exceed 8 Mt by 2030. It's an opportunity to take advantage of H2S prospects to be a crucial component of a clean safe and cost-effective sustainable future. This paper assesses the situation regarding H2 at the moment and provides recommendations for its potential future advancement. The study reveals that clean H2 is experiencing significant unparalleled commercial and political force with the amount of laws and projects all over the globe growing quickly. The paper concludes that in order to make H2 more widely employed it is crucial to significantly increase innovations and reduce costs. The practical and implementable suggestions provided to industries and governments will allow them to fully capitalise on this growing momentum.
The Role of Hydrogen in a Decarbonised Future Transport Sector: A Case Study of Mexico
Sep 2023
Publication
In recent years several approaches and pathways have been discussed to decarbonise the transport sector; however any effort to reduce emissions might be complex due to specific socio-economic and technical characteristics of different regions. In Mexico the transport sector is the highest energy consumer representing 38.9% of the national final energy demand with gasoline and diesel representing 90% of the sector´s total fuel consumption. Energy systems models are powerful tools to obtain insights into decarbonisation pathways to understand costs emissions and rate of deployment that could serve for energy policy development. This paper focuses on the modelling of the current Mexican transport system using the MUSE-MX multi-regional model with the aim to project a decarbonisation pathway through two different scenarios. The first approach being business as usual (BAU) which aims to analyse current policies implementation and the second being a goal of net zero carbon emissions by 2050. Under the considered net zero scenario results show potential deployment of hydrogen-based transport technologies especially for subsectors such as lorries (100% H2 by 2050) and freight train (25% H2 by 2050) while cars and buses tend to full electrification by 2050.
Hydrogen Storage for a Net-zero Carbon Future
Apr 2023
Publication
If a hydrogen economy is to become a reality along with efficient and decarbonized production and adequate transportation infrastructure deployment of suitable hydrogen storage facilities will be crucial. This is because due to various technical and economic reasons there is a serious possibility of an imbalance between hydrogen supply and demand. Hydrogen storage could also be pivotal in promoting renewable energy sources and facilitating the decarbonization process by providing long duration storage options which other forms of energy storage such as batteries with capacity limitations or pumped hydro with geographical limitations cannot meet. However hydrogen is not the easiest substance to store and handle. Under ambient conditions the extremely low volumetric energy density of hydrogen does not allow for its efficient and economic storage which means it needs to be compressed liquefied or converted into other substances that are easier to handle and store. Currently there are different hydrogen storage solutions at varying levels of technology market and commercial readiness with different applications depending on the circumstances. This paper evaluates the relative merits and techno-economic features of major types of hydrogen storage options: (i) pure hydrogen storage (ii) synthetic hydrocarbons (iii) chemical hydrides (iv) liquid organic hydrogen carriers (v) metal hydrides and (vi) porous materials. The paper also discusses the main barriers to investment in hydrogen storage and highlights key features of a viable business model in particular the policy and regulatory framework needed to address the primary risks to which potential hydrogen storage investors are exposed.
Hydrogen Embrittlement Characteristics in Cold-drawn High-strength Stainless Steel Wires
Mar 2023
Publication
Hydrogen uptake and embrittlement characteristics of a cold-drawn austenitic stainless steel wire were investigated. Slow strain rate testing and fracture surface analysis were applied to determine the hydrogen embrittlement resistance providing an apparent decrease in resistance to hydrogen embrittlement for a 50% degree of cold deformation. The hydrogen content was assessed by thermal desorption and laser-induced breakdown spectroscopy establishing a correlation between the total absorbed hydrogen and the intensity of near-surface hydrogen. The sub-surface hydrogen content of the hot-rolled specimen was determined to be 791 wt.ppm.
Precise Dynamic Modelling of Real-World Hybrid Solar-Hydrogen Energy Systems for Grid-Connected Buildings
Jul 2023
Publication
Hybrid renewable hydrogen energy systems could play a key role in delivering sustainable solutions for enabling the Net Zero ambition; however the lack of exact computational modelling tools for sizing the integrated system components and simulating their real-world dynamic behaviour remains a key technical challenge against their widespread adoption. This paper addresses this challenge by developing a precise dynamic model that allows sizing the rated capacity of the hybrid system components and accurately simulating their real-world dynamic behaviour while considering effective energy management between the grid-integrated system components to ensure that the maximum possible proportion of energy demand is supplied from clean sources rather than the grid. The proposed hybrid system components involve a solar PV system electrolyser pressurised hydrogen storage tank and fuel cell. The developed hybrid system model incorporates a set of mathematical models for the individual system components. The developed precise dynamic model allows identifying the electrolyser’s real-world hydrogen production levels in response to the input intermittent solar energy production while also simulating the electrochemical behaviour of the fuel cell and precisely quantifying its real-world output power and hydrogen consumption in response to load demand variations. Using a university campus case study building in Scotland the effectiveness of the developed model has been assessed by benchmarking comparison between its results versus those obtained from a generic model in which the electrochemical characteristics of the electrolyser and fuel cell systems were not taken into consideration. Results from this comparison have demonstrated the potential of the developed model in simulating the real-world dynamic operation of hybrid solar hydrogen energy systems for grid-connected buildings while sizing the exact capacity of system components avoiding oversizing associated with underutilisation costs and inaccurate simulation.
Discharge Modeling of Large Scale LH2 Experiments with an Engineering Tool
Sep 2021
Publication
Accurate estimation of mass flow rate and release conditions is important for the design of dispersion and combustion experiments for the subsequent validation of CFD codes/models for consequence assessment analysis within related risk assessment studies and for associated Regulation Codes and Standards development. This work focuses on the modelling of the discharge phase of the recent large scale LH2 release and dispersion experiments performed by HSE within the framework of PRESLHY project. The experimental conditions covered sub-cooled liquid stagnation conditions at two pressures (2 and 6 bara) and 3 release nozzle diameters (1 ½ and ¼ inches). The simulations were performed using a 1d engineering tool which accounts for discharge line effects due to friction extra resistance due to fittings and area change. The engineering tool uses the Possible Impossible Flow (PIF) algorithm for choked flow calculations and the Helmholtz Free Energy (HFE) EoS formulation. Three different phase distribution models were applied. The predictions are compared against measured and derived data from the experiments and recommendations are given both regarding engineering tool applicability and future experimental design.
A Low-temperature Ammonia Electrolyser for Wastewater Treatment and Hydrogen Production
May 2023
Publication
Ammonia is a pollutant present in wastewater and is also a valuable carbon-free hydrogen carrier. Stripping recovery and anodic oxidation of ammonia to produce hydrogen via electrolysis is gaining momentum as a technology yet the development of an inexpensive stable catalytic material is imperative to reduce cost. Here we report on a new nickel copper (NiCu) catalyst electrodeposited onto a high surface area nickel felt (NF) as an anode for ammonia electrolysis. Cyclic voltammetry demonstrated that the catalyst/substrate combination reached the highest current density (200 mA cm2 at 20 C) achieved for a non-noble metal catalyst. A NiCu/NF electrode was tested in an anion exchange membrane electrolyser for 50 h; it showed good stability and high Faradaic efficiency for ammonia oxidation (88%) and hydrogen production (99%). We demonstrate that this novel electrode catalyst/substrate material combination can oxidise ammonia in a scaled system and hydrogen can be produced as a valuable by-product at industrial-level current densities and cell voltages lower than that for water electrolysis.
A Review of Liquid Hydrogen Aircraft and Propulsion Technologies
Jan 2024
Publication
Sustainable aviation is a key part of achieving Net Zero by 2050 and is arguably one of the most challenging sectors to decarbonise. Hydrogen has gained unprecedented attention as a future fuel for aviation for use within fuel cell or hydrogen gas turbine propulsion systems. This paper presents a survey of the literature and industrial projects on hydrogen aircraft and associated enabling technologies. The current and predicted technology capabilities are analysed to identify important trends and to assess the feasibility of hydrogen propulsion. Several key enabling technologies are discussed in detail and gaps in knowledge are identified. It is evident that hydrogen propelled aircraft are technologically viable by 2050. However convergence of a number of critical factors is required namely: the extent of industrial collaboration the understanding of environmental science and contrails green hydrogen production and its availability at the point of use and the safety and certification of the aircraft and supporting infrastructure.
Thermochemical Looping Technologies for Clean Hydrogen Production – Current Status and Recent Advances
Nov 2022
Publication
This review critically analyses various aspects of the most promising thermochemical cycles for clean hydrogen production. While the current hydrogen market heavily relies on fossil-fuel-based platforms the thermochemical water-splitting systems based on the reduction-oxidation (redox) looping reactions have a significant potential to significantly contribute to the sustainable production of green hydrogen at scale. However compared to the water electrolysis techniques the thermochemical cycles suffer from a low technology readiness level (TRL) which retards the commercial implementation of these technologies. This review mainly focuses on identifying the capability of the state-of-the-art thermochemical cycles to deploy large-scale hydrogen production plants and their techno-economic performance. This study also analyzed the potential integration of the hybrid looping systems with the solar and nuclear reactor designs which are evidenced to be more cost-effective than the electrochemical water-splitting methods but it excludes fossil-based thermochemical processes such as gasification steam methane reforming and pyrolysis. Further investigation is still required to address the technical issues associated with implementing the hybrid thermochemical cycles in order to bring them to the market for sustainable hydrogen production.
Resilience-oriented Operation of Microgrids in the Presence of Power-to-hydrogen Systems
Jul 2023
Publication
This study presents a novel framework for improving the resilience of microgrids based on the power-to-hydrogen concept and the ability of microgrids to operate independently (i.e. islanded mode). For this purpose a model is being developed for the resilient operation of microgrids in which the compressed hydrogen produced by power-to-hydrogen systems can either be used to generate electricity through fuel cells or sold to other industries. The model is a bi-objective optimization problem which minimizes the cost of operation and resilience by (i) reducing the active power exchange with the main grid (ii) reducing the ohmic power losses and (iii) increasing the amount of hydrogen stored in the tanks. A solution approach is also developed to deal with the complexity of the bi-objective model combining a goal programming approach and Generalized Benders Decomposition due to the mixed-integer nonlinear nature of the optimization problem. The results indicate that the resilience approach although increasing the operation cost does not lead to load shedding in the event of main grid failures. The study concludes that integrating distributed power-to-hydrogen systems results in significant benefits including emission reductions of up to 20 % and cost savings of up to 30 %. Additionally the integration of the decomposition method improves computational performance by 54 % compared to using commercial solvers within the GAMS software.
The ATHENA Framework: Analysis and Design of a Strategic Hydrogen Refuelling Infrastructure
Apr 2023
Publication
With the pressured timescale in determining effective and viable net zero solutions within the transport sector it is important to understand the extent of implementing a new refuelling infrastructure for alternative fuel such as hydrogen. The proposed ATHENA framework entails three components which encapsulates the demand data analysis an optimisation model in determining the minimal cost hydrogen refuelling infrastructure design and an agent-based model simulating the operational system. As a case study the ATHENA framework is applied to Northern England focusing on the design of a hydrogen refuelling infrastructure for heavy goods vehicles. Analysis is performed in calibrating parameters and investigating different scenarios within the optimisation and agent-based simulation models. For this case study the system optimality is limited by the feasible number of tube trailer deliveries per day which suggests an opportunity for alternative delivery methods.
Review and Survey of Methods for Analysis of Impurities in Hydrogen for Fuel Cell Vehicles According to ISO 14687:2019
Feb 2021
Publication
Gaseous hydrogen for fuel cell electric vehicles must meet quality standards such as ISO 14687:2019 which contains maximal control thresholds for several impurities which could damage the fuel cells or the infrastructure. A review of analytical techniques for impurities analysis has already been carried out by Murugan et al. in 2014. Similarly this document intends to review the sampling of hydrogen and the available analytical methods together with a survey of laboratories performing the analysis of hydrogen about the techniques being used. Most impurities are addressed however some of them are challenging especially the halogenated compounds since only some halogenated compounds are covered not all of them. The analysis of impurities following ISO 14687:2019 remains expensive and complex enhancing the need for further research in this area. Novel and promising analyzers have been developed which need to be validated according to ISO 21087:2019 requirements.
The Impact of the Energy Crisis on the UK's Net Zero Transition
Mar 2023
Publication
Recent drastic increases in natural gas prices have brought into sharp focus the inherent tensions between net zero transitions energy security and affordability. We investigate the impact of different fuel prices on the energy system transition explicitly accounting for the increasingly coupled power and heating sectors and also incorporate the emerging hydrogen sector. The aim is to identify low-regret decisions and optimal energy system transitions for different fuel prices. We observe that the evolution of the heating sector is highly sensitive to the gas price whereas the composition of the power sector is not qualitatively impacted by gas prices. We also observe that bioenergy plays an important role in the energy system transition and the balance between gas price and biomass prices determines the optimal technology portfolios. The future evolution of the prices of these two resources is highly uncertain and future energy systems must be resilient to these uncertainties.
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
Developments in Hydrogen Fuel Cells
Mar 2023
Publication
The rapid growth in fossil fuels has resulted in climate change that needs to be controlled in the near future. Several methods have been proposed to control climate change including the development of efficient energy conversion devices. Fuel cells are environmentally friendly energy conversion devices that can be fuelled by green hydrogen with only water as a by-product or by using different biofuels such as biomass in wastewater urea in wastewater biogas from municipal and agricultural wastes syngas from agriculture wastes and waste carbon. This editorial discusses the fundamentals of the operation of the fuel cell and their application in various sectors such as residential transportation and power generation.
Design and Optimization of a Type-C Tank for Liquid Hydrogen Marine Transport
May 2023
Publication
As one of the most promising renewable energy sources hydrogen has the excellent environmental benefit of producing zero emissions. A key technical challenge in using hydrogen across sectors is placed on its storage technology. The storage temperature of liquid hydrogen (20 K or 253 C) is close to absolute zero so the storage materials and the insulation layers are subjected to extremely stringent requirements against the cryogenic behaviour of the medium. In this context this research proposed to design a large liquid hydrogen type-C tank with AISI (American Iron and Steel Institution) type 316 L stainless steel as the metal barrier using Vapor-Cooled Shield (VCS) and Rigid Polyurethane Foams (RPF) as the insulation layer. A parametric study on the design of the insulation layer was carried out by establishing a thermodynamic model. The effects of VCS location on heat ingress to the liquid hydrogen transport tank and insulation temperature distribution were investigated and the optimal location of the VCS in the insulation was identified. Research outcomes finally suggest two optimal design schemes: (1) when the thickness of the insulation layer is determined Self-evaporation Vapor-Cooled Shield (SVCS) and Forcedevaporation Vapor-Cooled Shield (FVCS) can reduce heat transfer by 47.84% and 85.86% respectively; (2) when the liquid hydrogen evaporation capacity is determined SVCS and FVCS can reduce the thickness of the insulation layer by 50% and 67.93% respectively.
Technology Pathways, Efficiency Gains and Price Implications of Decarbonising Residential Heat in the UK
Jun 2023
Publication
The UK government’s plans to decarbonise residential heating will mean major changes to the energy system whatever the specific technology pathway chosen driving a range of impacts on users and suppliers. We use an energy system model (UK TIMES) to identify the potential energy system impacts of alternative pathways to low or zero carbon heating. We find that the speed of transitioning can affect the network investment requirements the overall energy use and emissions generated while the primary heating fuel shift will determine which sectors and networks require most investment. Crucially we identify that retail price differences between heating fuels in the UK particularly gas and electricity could erode or eliminate bill savings from switching to more efficient heating systems.
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.
OIES Podcast - China and Hydrogen: A Tale of Three Cities
Apr 2023
Publication
China is by far the world’s largest producer and consumer of hydrogen mostly from coal and other fossil fuels and the country has an ambitious hydrogen strategy. In this podcast we dive into the provincial strategies on hydrogen in China and specifically discuss a recent paper published by the Institute entitled China’s hydrogen development: A tale of three cities. The paper looks at the experiences and plans of the pilot hydrogen clusters located in Datong Shanxi province Chengdu in Sichuan province and Zhangjiakou in the northern part of Hebei province which surrounds Beijing. In this podcast we are speaking with the paper’s author Arabella Miller-Wang recently an Aramco fellow at the Institute and also a Research Assistant at the Smith School of Enterprise and the Environment of The University of Oxford as well as with Michal Meidan director of the China Energy Programme at OIES and with Martin Lambert who heads hydrogen research at the OIES.
The podcast can be found on their website.
The podcast can be found on their website.
Modelling Large-scale Hydrogen Uptake in the Mexican Refinery and Power Sectors
Sep 2023
Publication
Due to the emissions reduction commitments that Mexico compromised in the Paris Agreement several clean fuel and renewable energy technologies need to penetrate the market to accomplish the environmental goals. Therefore there is a need to develop achievable and realistic policies for such technologies to ease the decision-making on national energy strategies. Several countries are starting to develop large-scale green hydrogen production projects to reduce the carbon footprint of the multiple sectors within the country. The conversion sectors namely power and refinery are fundamental sectors to decarbonise due to their energy supply role. Nowadays the highest energy consumables of the country are hydrocarbons (more than 90%) causing a particular challenge for deep decarbonisation. The purpose of this study is to use a multi-regional energy system model of Mexico to analyse a decarbonisation scenario in line with the latest National Energy System Development Program. Results show that if the country wants to succeed in reducing 22% of its GHG emissions and 51% of its short-lived climate pollutants emissions green hydrogen could play a role in power generation in regions with higher energy demand growth rates. These results show regarding the power sector that H2 could represent 13.8 GW or 5.1% of the total installed capacity by 2050 while for the refinery sector H2 could reach a capacity of 157 PJ/y which is around 31.8% of the total share and it is mainly driven by the increasing demands of the transport industry and power sectors. Nevertheless as oil would still represent the largest energy commodity CCS technologies would have to be deployed for new and retrofitted refinery facilities.
H21 Phase 2 Technical Summary Report
Jul 2023
Publication
The H21 Phase 2 research will provide vital evidence both towards the hydrogen village trial and potential town scale pilots and to the Government which is aiming to make a decision about the use of hydrogen for home heating by 2026.
The key objectives of the H21 Phase 2 NIC project were to further develop the evidence base supporting conversion of the natural gas distribution network to 100% hydrogen. The key principles of H21 NIC Phase 2 were to:
→ Confirm how we can manage and operate the network safely through an appraisal of existing network equipment procedures and network modelling tools.
→ Validate network operations on a purpose-built below 7 barg network as well as an existing unoccupied buried network and provide a platform to publicise and demonstrate a hydrogen network in action.
→ Develop a combined distribution network and downstream Quantitative Risk Assessment (QRA) for 100% hydrogen by further developing the work undertaken on the H21 Phase 1 QRA and the Hy4Heat ‘downstream of ECV’ QRA.
→ Continue to understand how consumers could be engaged with ahead of a conversion. This programme was split into four phases detailed below:
→ Phase 2a – Appraisal of Network 0-7 bar Operations
→ Phase 2b – Unoccupied Network Trials
→ Phase 2c – Combined QRA
→ Phase 2d – Social Sciences
The project with the support of the HSE’s Science & Research Centre (HSE S&RC) and DNV successfully undertook a programme of work to review the NGN below 7 barg network operating procedures. The project implemented testing and demonstrations on the Phase 2a Microgrid at DNV Spadeadam and Phase 2b Unoccupied Trial site in South Bank on a repurposed NGN network to provide and demonstrate the supporting evidence for the required changes to procedures. Details of the outputs of the HSE S&RC procedure review and the evidence collected by DNV from the testing and demonstration projects is provided in detail in this technical summary report.
Due to the differences in gas characteristics between hydrogen and natural gas changes will be required to some of the operational and maintenance procedures the evidence of which is provided in this report. The Gas Distribution Networks (GDNs) will need to review the findings from this project when implementing the required changes to their operational and maintenance procedures.
The key objectives of the H21 Phase 2 NIC project were to further develop the evidence base supporting conversion of the natural gas distribution network to 100% hydrogen. The key principles of H21 NIC Phase 2 were to:
→ Confirm how we can manage and operate the network safely through an appraisal of existing network equipment procedures and network modelling tools.
→ Validate network operations on a purpose-built below 7 barg network as well as an existing unoccupied buried network and provide a platform to publicise and demonstrate a hydrogen network in action.
→ Develop a combined distribution network and downstream Quantitative Risk Assessment (QRA) for 100% hydrogen by further developing the work undertaken on the H21 Phase 1 QRA and the Hy4Heat ‘downstream of ECV’ QRA.
→ Continue to understand how consumers could be engaged with ahead of a conversion. This programme was split into four phases detailed below:
→ Phase 2a – Appraisal of Network 0-7 bar Operations
→ Phase 2b – Unoccupied Network Trials
→ Phase 2c – Combined QRA
→ Phase 2d – Social Sciences
The project with the support of the HSE’s Science & Research Centre (HSE S&RC) and DNV successfully undertook a programme of work to review the NGN below 7 barg network operating procedures. The project implemented testing and demonstrations on the Phase 2a Microgrid at DNV Spadeadam and Phase 2b Unoccupied Trial site in South Bank on a repurposed NGN network to provide and demonstrate the supporting evidence for the required changes to procedures. Details of the outputs of the HSE S&RC procedure review and the evidence collected by DNV from the testing and demonstration projects is provided in detail in this technical summary report.
Due to the differences in gas characteristics between hydrogen and natural gas changes will be required to some of the operational and maintenance procedures the evidence of which is provided in this report. The Gas Distribution Networks (GDNs) will need to review the findings from this project when implementing the required changes to their operational and maintenance procedures.
Design Investigation of Potential Long-Range Hydrogen Combustion Blended Wing Body Aircraft with Future Technologies
Jun 2023
Publication
Present work investigates the potential of a long-range commercial blended wing body configuration powered by hydrogen combustion engines with future airframe and propulsion technologies. Future technologies include advanced materials load alleviation techniques boundary layer ingestion and ultra-high bypass ratio engines. The hydrogen combustion configuration was compared to the configuration powered by kerosene with respect to geometric properties performance characteristics energy demand equivalent CO2 emissions and Direct Operating Costs. In addition technology sensitivity studies were performed to assess the potential influence of each technology on the configuration. A multi-fidelity sizing methodology using low- and mid-fidelity methods for rapid configuration sizing was created to assess the configuration and perform robust analyses and multi-disciplinary optimizations. To assess potential uncertainties of the fidelity of aerodynamic analysis tools high-fidelity aerodynamic analysis and optimization framework MACHAero was used for additional verification. Comparison of hydrogen and kerosene blended wing body aircraft showed a potential reduction of equivalent CO2 emission by 15% and 81% for blue and green hydrogen compared to the kerosene blended wing body and by 44% and 88% with respect to a conventional B777-300ER aircraft. Advancements in future technologies also significantly affect the geometric layout of aircraft. Boundary layer ingestion and ultra-high bypass ratio engines demonstrated the highest potential for fuel reduction although both technologies conflict with each other. However operating costs of hydrogen aircraft could establish a significant problem if pessimistic and base hydrogen price scenarios are achieved for blue and green hydrogen respectively. Finally configurational problems featured by classical blended wing body aircraft are magnified for the hydrogen case due to the significant volume requirements to store hydrogen fuel.
Techno-economic Analysis of Large-scale Green Hydrogen Production and Storage
Jun 2023
Publication
Producing clean energy and minimising energy waste are essential to achieve the United Nations sustainable development goals such as Sustainable Development Goal 7 and 13. This research analyses the techno-economic potential of waste heat recovery from multi-MW scale green hydrogen production. A 10 MW proton exchange membrane electrolysis process is modelled with a heat recovery system coupled with an organic Rankine cycle (ORC) to drive the mechanical compression of hydrogen. The technical results demonstrate that when implementing waste heat recovery coupled with an ORC the first-law efficiency of electrolyser increases from 71.4% to 98%. The ORC can generate sufficient power to drive the hydrogen's compression from the outlet pressure at the electrolyser 30 bar up to 200 bar. An economic analysis is conducted to calculate the levelised cost of hydrogen (LCOH) of system and assess the feasibility of implementing waste heat recovery coupled with ORC. The results reveal that electricity prices dominate the LCOH. When electricity prices are low (e.g. dedicated offshore wind electricity) the LCOH is higher when implementing heat recovery. The additional capital expenditure and operating expenditure associated with the ORC increases the LCOH and these additional costs outweigh the savings generated by not purchasing electricity for compression. On the other hand heat recovery and ORC become attractive and feasible when grid electricity prices are higher.
Techno-economic Analysis of Direct Air Carbon Capture and Hydrogen Production Integrated with a Small Modular Reactor
Dec 2023
Publication
This study aims to explore the techno-economic potential of harnessing waste heat from a Small Modular Reactor (SMR) to fuel Direct Air Carbon Capture (DACC) and High Temperature Steam Electrolysis (HTSE) technologies. The proposed system’s material flows and energy demands are modelled via the ASPEN Plus v12.1 where results are utilised to provide estimates of the Levelised Cost of DACC (LCOD) and Levelised Cost of Hydrogen (LCOH). The majority of thermal energy and electrical utilities are assumed to be supplied directly by the SMR. A sensitivity analysis is then performed to investigate the effects of core operational parameters of the system. Key results indicate levelised costs of 4.66 $/kgH2 at energy demands of 34.37 kWh/kgH2 and 0.02 kWh/kgH2 thermal for HTSE hydrogen production and 124.15 $/tCO2 at energy demands of 31.67 kWh/tCO2 and 126.33 kWh/tCO2 thermal for carbon capture; parameters with most impact on levelised costs are air intake and steam feed for LCOD and LCOH respectively. Both levelised costs i.e. LCOD and LCOH would decrease with the production scale. The study implies that an integrated system of DACC and HTSE provided the best cost-benefit results however the cost-benefit analysis is heavily subjective to geography politics and grid demand.
Hydrogen Liquefaction: A Review of the Fundamental Physics, Engineering Practice and Future Opportunities
Apr 2022
Publication
Hydrogen is emerging as one of the most promising energy carriers for a decarbonised global energy system. Transportation and storage of hydrogen are critical to its large-scale adoption and to these ends liquid hydrogen is being widely considered. The liquefaction and storage processes must however be both safe and efficient for liquid hydrogen to be viable as an energy carrier. Identifying the most promising liquefaction processes and associated transport and storage technologies is therefore crucial; these need to be considered in terms of a range of interconnected parameters ranging from energy consumption and appropriate materials usage to considerations of unique liquid-hydrogen physics (in the form of ortho–para hydrogen conversion) and boil-off gas handling. This study presents the current state of liquid hydrogen technology across the entire value chain whilst detailing both the relevant underpinning science (e.g. the quantum behaviour of hydrogen at cryogenic temperatures) and current liquefaction process routes including relevant unit operation design and efficiency. Cognisant of the challenges associated with a projected hydrogen liquefaction plant capacity scale-up from the current 32 tonnes per day to greater than 100 tonnes per day to meet projected hydrogen demand this study also reflects on the next-generation of liquid-hydrogen technologies and the scientific research and development priorities needed to enable them.
‘Greening’ an Oil Exporting Country: A Hydrogen, Wind and Gas Turbine Case Study
Feb 2024
Publication
In the quest for achieving decarbonisation it is essential for different sectors of the economy to collaborate and invest significantly. This study presents an innovative approach that merges technological insights with philosophical considerations at a national scale with the intention of shaping the national policy and practice. The aim of this research is to assist in formulating decarbonisation strategies for intricate economies. Libya a major oil exporter that can diversify its energy revenue sources is used as the case study. However the principles can be applied to develop decarbonisation strategies across the globe. The decarbonisation framework evaluated in this study encompasses wind-based renewable electricity hydrogen and gas turbine combined cycles. A comprehensive set of both official and unofficial national data was assembled integrated and analysed to conduct this study. The developed analytical model considers a variety of factors including consumption in different sectors geographical data weather patterns wind potential and consumption trends amongst others. When gaps and inconsistencies were encountered reasonable assumptions and projections were used to bridge them. This model is seen as a valuable foundation for developing replacement scenarios that can realistically guide production and user engagement towards decarbonisation. The aim of this model is to maintain the advantages of the current energy consumption level assuming a 2% growth rate and to assess changes in energy consumption in a fully green economy. While some level of speculation is present in the results important qualitative and quantitative insights emerge with the key takeaway being the use of hydrogen and the anticipated considerable increase in electricity demand. Two scenarios were evaluated: achieving energy self-sufficiency and replacing current oil exports with hydrogen exports on an energy content basis. This study offers for the first time a quantitative perspective on the wind-based infrastructure needs resulting from the evaluation of the two scenarios. In the first scenario energy requirements were based on replacing fossil fuels with renewable sources. In contrast the second scenario included maintaining energy exports at levels like the past substituting oil with hydrogen. The findings clearly demonstrate that this transition will demand great changes and substantial investments. The primary requirements identified are 20529 or 34199 km2 of land for wind turbine installations (for self-sufficiency and exports) and 44 single-shaft 600 MW combined-cycle hydrogen-fired gas turbines. This foundational analysis represents the commencement of the research investment and political agenda regarding the journey to achieving decarbonisation for a country.
Future of Hydrogen in Industry: Initial Industrial Site Surveys
Jul 2023
Publication
This is a summary report of a study which aimed to understand the safety feasibility cost and impacts for 7 industrial sites to switch from natural gas to 100% hydrogen for heating. The volunteer industrial sites:<br/>♦ are located away from industrial clusters<br/>♦ use natural gas to meet most of their energy demand<br/>♦ will likely be most impacted by decisions on the future of the natural gas grid<br/>We have published the report in order to share its findings with other industrial sites and wider industry in particular those considering hydrogen as an option for decarbonisation.<br/>Note that:<br/>♦ some work was carried out on a non-hydrogen alternative energy source but to a lesser level of detail and not to determine the optimal decarbonisation solution<br/>♦ the findings do not apply to other end user environments because of differences between these environments and the consumption of gas<br/>The study was commissioned in 2022 by the former Department for Business and Energy and undertaken by AECOM and their safety sub-contractor ESR.<br/>The evidence will inform strategic decisions in 2026 on the role of low carbon hydrogen as a replacement for natural gas heating.
A Hydrogen Vision for the UK
Apr 2023
Publication
This report shows how the infrastructure that exists today can evolve from one based on the supply of fossil fuels to one providing the backbone of a clean hydrogen system. The ambitious government hydrogen targets across the UK will only be met with clarity focus and partnership. The gas networks are ready to play their part in the UK’s energy future. They have a plan know what is needed to deliver it and are taking the necessary steps to do just that.
Hydrogen from Offshore Wind: Investor Perspective on the Profitability of a Hybrid System Including for Curtailment
Mar 2020
Publication
Accommodating renewables on the electricity grid may hinder development opportunities for offshore wind farms (OWFs) as they begin to experience significant curtailment or constraint. However there is potential to combine investment in OWFs with Power-to-Gas (PtG) converting electricity to hydrogen via electrolysis for an alternative/complementary revenue. Using historic wind speed and simulated system marginal costs data this work models the electricity generated and potential revenues of a 504 MW OWF. Three configurations are analysed; (1) all electricity is sold to the grid (2) all electricity is converted to hydrogen and sold and (3) a hybrid system where power is converted to hydrogen when curtailment occurs and/or when the system marginal cost is low with the effect of curtailment analysed in each scenario. These represent the status quo a potential future configuration and an innovative business model respectively. The willingness of an investor to build PtG are determined by changes to the net present value (NPV) of a project. Results suggest that configuration (1) is most profitable and that curtailment mitigation alone is not sufficient to secure investment in PtG. By acting as an artificial floor in the electricity price a hybrid configuration (3) is promising and increases NPV for all hydrogen values greater than €4.2/kgH2. Hybrid system attractiveness increases with curtailment only if the hydrogen value is significantly above the levelised cost of €3.77/kgH2. In order for an investor to choose to pursue configuration (2) the offshore wind farm would have to anticipate 8.5% curtailment and be able to receive €4.5/kgH2 or 25% curtailment and receive €4/kgH2. The capital costs and discount rates are the most sensitive parameters and ambitious combinations of technology improvements could produce a levelised cost of €3/kgH2.
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
OIES Podcast - The EU Hydrogen and Gas Decarbonisation Package
Mar 2023
Publication
David Ledesma discusses with Alex Barnes the European Commission’s decision to make hydrogen a key part of its decarbonisation strategy. The 2022 REPowerEU Strategy set a target of 20MT consumption of renewable hydrogen by 2030. The Commission is keen to promote a single European market in hydrogen similar to the current one for natural gas. To this end it has published proposals on the regulation of future European hydrogen infrastructure (pipelines storage facilities and import terminals). The EU Council (representing Member States) and the EU Parliament are finalising their amendments to the Commission proposals prior to ‘trilogue’ negotiations and final agreement later this year. The OIES’s paper ‘The EU Hydrogen and Gas Decarbonisation Package: help or hindrance for the development of a European hydrogen market?’ published in March 2023 examines the EU Commission proposals and their suitability for a developing hydrogen market.
The podcast can be found on their website.
The podcast can be found on their website.
Coordinated Control of a Wind-Methanol-Fuel Cell System with Hydrogen Storage
Dec 2017
Publication
This paper presents a wind-methanol-fuel cell system with hydrogen storage. It can manage various energy flow to provide stable wind power supply produce constant methanol and reduce CO2 emissions. Firstly this study establishes the theoretical basis and formulation algorithms. And then computational experiments are developed with MATLAB/Simulink (R2016a MathWorks Natick MA USA). Real data are used to fit the developed models in the study. From the test results the developed system can generate maximum electricity whilst maintaining a stable production of methanol with the aid of a hybrid energy storage system (HESS). A sophisticated control scheme is also developed to coordinate these actions to achieve satisfactory system performance.
China's Hydrogen Development: A Tale of Three Cities
Mar 2023
Publication
China is the world’s largest producer and consumer of hydrogen. The country has adopted a domestic strategy that targets significant growth in hydrogen consumption and production. Given the importance of hydrogen in the low-carbon energy transition it is critical to understand China’s hydrogen policies and their implementation as well as the extent to which these contribute to the country’s low-carbon goals.<br/>Existing research has focused on understanding policies and regulations in China and their implications for the country’s hydrogen prospects. This study aims to improve our understanding of central-government initiatives and look at how China’s hydrogen policies are implemented at the local level. The paper examines the three cities of Zhangjiakou (in China’s renewable-rich Hebei province) Datong (in the country’s coal-heartland of Shanxi province) and Chengdu which is rich in hydropower and natural gas. To be sure the three cities analysed in this paper do not cover all regional plans and initiatives but they offer a useful window into local hydrogen policy implementation. They also illustrate the major challenges facing green hydrogen as it moves beyond the narrow highly subsidized field of fuel cell vehicles (FCVs). Indeed costs as well as water land availability and technology continue to be constraints.<br/>The hydrogen policies and road maps reviewed in this paper offer numerous targets—often setting quantitative goals for FCVs hydrogen refuelling stations hydrogen supply chain revenue and new hydrogen technology companies—aligning with the view that hydrogen development is currently more of an industrial policy than a decarbonisation strategy. Indeed hydrogen’s potential to decarbonise sectors such as manufacturing and chemicals is of secondary importance if mentioned at all. But as the cities analysed here view hydrogen as part of their industrial programmes economic development and climate strategies support is likely to remain significant even as the specific incentive schemes will likely evolve.<br/>Given this local hydrogen development model rising demand for hydrogen in China could ultimately increase rather than decrease CO₂ emissions from fossil fuels in the short run. At the same time even though the central government’s hydrogen targets (as laid out in its 2022 policy documents) seem relatively conservative Chinese cities’ appetite for new sources of growth and the ability to fund various business models are worth watching.
Modelling Underground Hydrogen Storage: A State-of-the-art Review of Fundamental Approaches and Findings
Dec 2023
Publication
This review presents a state-of-the-art of geochemical geomechanical and hydrodynamic modelling studies in the Underground Hydrogen Storage (UHS) domain. Geochemical modelling assessed the reactivity of hydrogen and res pective fluctuations in hydrogen losses using kinetic reaction rates rock mineralogy brine salinity and the integration of hydrogen redox reactions. Existing geomechanics studies offer an array of coupled hydromechanical models suggesting a decline in rock failure during the withdrawal phase in aquifers compared to injection phase. Hydrodynamic modelling evaluations indicate the critical importance of relative permeability hysteresis in determining the UHS performance. Solubility and diffusion of hydrogen gas appear to have minimal impact on UHS. Injection and production rates cushion gas deployment and reservoir heterogeneity however significantly affect the UHS performance stressing the need for thorough modelling and experimental studies. Most of the current UHS modelling efforts focus on assessing the hydrodynamic aspects which are crucial for understanding the viability and safety of UHS. In contrast the lesser-explored geochemical and geomechanical considerations point to potential research gaps. A variety of modelling software tools such as CMG Eclipse COMSOL and PHREEQC evaluated those UHS underlying effects along with a few recent applications of datadriven-based Machine Learning (ML) techniques for enhanced accuracy. This review identified several unresolved challenges in UHS modelling: pronounced lack of expansive datasets leading to a gap between model predictions and their practical reliability; need robust methodologies capable of capturing natural subsurface heterogeneity while upscaling from precise laboratory data to field-scale conditions; demanding intensive computational resources and novel strategies to enhance simulation efficiency; and a gap in addressing geological uncertainties in subsurface environments suggesting that methodologies from oil reservoir simulations could be adapted for UHS. This comprehensive review offers a critical synthesis of the prevailing approaches challenges and research gaps in the domain of UHS thus providing a valuable reference document for further modelling efforts facilitating the informed advancements in this critical domain towards the realization of sustainable energy solutions.
Emission Reduction and Cost-benefit Analysis of the Use of Ammonia and Green Hydrogen as Fuel for Marine Applications
Dec 2023
Publication
Increasingly stringent emission standards have led shippers and port operators to consider alternative energy sources which can reduce emissions while minimizing capital investment. It is essential to understand whether there is a certain economic investment gap for alternative energy. The present work mainly focuses on the simulation study of ships using ammonia and hydrogen fuels arriving at Guangzhou Port to investigate the emission advantages and cost-benefit analysis of ammonia and hydrogen as alternative fuels. By collecting actual data and fuel consumption emissions of ships arriving at Guangzhou Port the present study calculated the pollutant emissions and cost of ammonia and hydrogen fuels substitution. As expected it is shown that with the increase of NH3 in fuel mixed fuels will effectively reduce CO and CO2 emissions. Compared to conventional fuel the injection of NH3 increases the NOx emission. However the cost savings of ammonia fuel for CO2 SOx and PM10 reduction are higher than that for NOx. In terms of pollutants ammonia is less expensive than conventional fuels when applied to the Guangzhou Port. However the cost of fuel supply is still higher than conventional energy as ammonia has not yet formed a complete fuel supply and storage system for ships. On the other hand hydrogen is quite expensive to store and transport resulting in higher overall costs than ammonia and conventional fuels even if no pollutants are produced. At present conventional fuels still have advantage in terms of cost. With the promotion of ammonia fuel technology and application the cost of supply will be reduced. It is predicted that by 2035 ammonia will not only have emission reduction benefits but also will have a lower overall economic cost than conventional fuels. Hydrogen energy will need longer development and technological breakthroughs due to the limitation of storage conditions.
Caveats of Green Hydrogen for Decarbonisation of Heating in Buildings
Oct 2023
Publication
Hydrogen (H2) has rapidly become a topic of great attention when discussing routes to net-zero carbon emissions. About 14% of CO2 emissions globally are directly associated with domestic heating in buildings. Replacing natural gas (NG) with H2 for heating has been highlighted as a rapid alternative for mitigating these emissions. To realise this not only the production challenges but also potential obstacles in the transmission/distribution and combustion of H2 must be technically identified and discussed. This review in addition to delineating the challenges of H2 in NG grid pipelines and H2 combustion also collates the results of the state-of-the-art technologies in H2-based heating systems. We conclude that the sustainability of water and renewable electricity resources strongly depends on sizing siting service life of electrolysis plants and post-electrolysis water disposal plans. 100% H2 in pipelines requires major infrastructure upgrades including production transmission pressurereduction stations distribution and boiler rooms. H2 leakage instigates more environmental risks than economic ones. With optimised boilers burning H2 could reduce GHG emissions and obtain an appropriate heating efficiency; more data from boiler manufacturers must be provided. Overall green H2 is not the only solution to decarbonise heating in buildings and it should be pursued abreast of other heating technologies.
Assessing the Potential of Decarbonization Options for Industrial Sectors
Jan 2024
Publication
Industry emits around a quarter of global greenhouse gas (GHG) emissions. This paper presents the first comprehensive review to identify the main decarbonization options for this sector and their abatement potentials. First we identify the important GHG emitting processes and establish a global average baseline for their current emissions intensity and energy use. We then quantify the energy and emissions reduction potential of the most significant abatement options as well as their technology readiness level (TRL). We find that energy-intensive industries have a range of decarbonization technologies available with medium to high TRLs and mature options also exist for decarbonizing low-temperature heat across a wide range of industrial sectors. However electrification and novel process change options to reduce emissions from high-temperature and sector-specific processes have much lower TRLs in comparison. We conclude by highlighting important barriers to the deployment of industrial decarbonization options and identifying future research development and demonstration needs.
Techno-economic Feasibility of Distributed Waste-to-hydrogen Systems to Support Green Transport in Glasgow
Mar 2022
Publication
Distributed waste-to-hydrogen (WtH) systems are a potential solution to tackle the dual challenges of sustainable waste management and zero emission transport. Here we propose a concept of distributed WtH systems based on gasification and fermentation to support hydrogen fuel cell buses in Glasgow. A variety of WtH scenarios were configured based on biomass waste feedstock hydrogen production reactors and upstream and downstream system components. A cost-benefit analysis (CBA) was conducted to compare the economic feasibility of the different WtH systems with that of the conventional steam methane reforming-based method. This required the curation of a database that included inter alia direct cost data on construction maintenance operations infrastructure and storage along with indirect cost data comprising environmental impacts and externalities cost of pollution carbon taxes and subsidies. The levelized cost of hydrogen (LCoH) was calculated to be 2.22 GB P/kg for municipal solid waste gasification and 2.02 GB P/kg for waste wood gasification. The LCoHs for dark fermentation and combined dark and photo fermentation systems were calculated to be 2.15 GB P/kg and 2.29 GB P/kg. Sensitivity analysis was conducted to identify the most significant influential factors of distributed WtH systems. It was indicated that hydrogen production rates and CAPEX had the largest impact for the biochemical and thermochemical technologies respectively. Limitations including high capital expenditure will require cost reduction through technical advancements and carbon tax on conventional hydrogen production methods to improve the outlook for WtH development.
Optimizing Underground Hydrogen Storage in Aquifers: The Impact of Cushion Gas Type
Aug 2023
Publication
This study investigated the impact of cushion gas type and presence on the performance of underground hydrogen storage (UHS) in an offshore North Sea aquifer. Using numerical simulation the relationship between cushion gas type and UHS performance was comprehensively evaluated providing valuable insights for designing an efficient UHS project delivery. Results indicated that cushion gas type can significantly impact the process's recovery efficiency and hydrogen purity. CO2 was found to have the highest storage capacity while lighter gases like N2 and CH4 exhibited better recovery efficiency. Utilising CH4 as a cushion gas can lead to a higher recovery efficiency of 80%. It was also determined that utilising either of these cushion gases was always more beneficial than hydrogen storage alone leading to an incremental hydrogen recovery up to 7%. Additionally hydrogen purity degraded as each cycle progressed but improved over time. This study contributes to a better understanding of factors affecting UHS performance and can inform the selection of cushion gas type and optimal operational strategies.
Towards a Unified Theory of Domestic Hydrogen Acceptance: An Integrative, Comparative Review
Dec 2023
Publication
Hydrogen energy technologies are envisioned to play a critical supporting role in global decarbonisation. While low-carbon hydrogen is primarily targeted for reducing industrial emissions alongside decarbonising parts of the transport sector environmental benefits could also be achieved in the residential context. Presently gasdependent countries such as Japan and the United Kingdom are assessing the feasibility of deploying hydrogen home appliances as part of their national energy strategies. However prospects for the transition will hinge on consumer acceptance alongside an array of other socio-technical factors. To support potential ambitions for large-scale and sustained technology diffusion this study advances a Unified Theory of Domestic Hydrogen Acceptance. Through an integrative comparative literature review targeting hydrogen and domestic energy studies the paper proposes a novel Domestic Hydrogen Acceptance Model (DHAM) which accounts for the cognitive and emotional dimensions of human perceptions. Through this dual interplay the proposed framework can increase the predictive power of hydrogen acceptance models.
Future Energy Scenarios 2022
Jul 2022
Publication
Future Energy Scenarios (FES) represent a range of different credible ways to decarbonise our energy system as we strive towards the 2050 target.<br/>We’re less than 30 years away from the Net Zero deadline which isn’t long when you consider investment cycles for gas networks electricity transmission lines and domestic heating systems.<br/>FES has an important role to play in stimulating debate and helping to shape the energy system of the future.
Explaining Varying Speeds of Low-carbon Reorientation in the United Kingdom's Steel, Petrochemical, and Oil Refining Industries: A Multi-dimensional Comparative Analysis and Outlook
Feb 2024
Publication
Accelerated decarbonisation of steelmaking oil refining and petrochemical industries is essential for climate change mitigation. Drawing on three longitudinal case studies of these industries in the UK this synthesis article makes a comparative analysis of their varying low-carbon reorientation speeds. The paper uses the triple embeddedness framework to analyse five factors (policy support international competition financial health technical feasibility corporate strategy and mindset) that explain why UK oil refineries have in recent years been comparatively the fastest in their low-carbon reorientation and UK steelmakers the slowest. We find that policy support has been more beneficial for refining and petrochemicals than for steel although recent government deals with steelmakers addressed this imbalance. International competition has been high for steel and petrochemicals and comparatively lower for refining (meaning that decarbonisation costs are less detrimental for international competitiveness). Financial performance has comparatively been worst for steel and best for oil refining which shapes the economic feasibility of low-carbon options. Hydrogen and carbon-capture-and-storage are technologically feasible for refining and petrochemicals while Electric Arc Furnaces are technically feasible for steelmakers but face wider feasibility problems (with scrap steel supply electricity grids and electricity prices) which is why we question the recent government deals. Corporate strategy and perceptions changed in oil refining with firms seeing economic opportunities in decarbonisation while steelmakers and petrochemical firms still mostly see decarbonisation as a burden and threat. The paper ends with comparative conclusions a discussion of political considerations and future outlooks for the three UK industries policy and research.
Future Energy Scenarios 2020
Jul 2020
Publication
Our Future Energy Scenarios (FES) outline four different credible pathways for the future of energy over the next 30 years. Based on input from over 600 experts the report looks at the energy needed in Britain across electricity and gas - examining where it could come from how it needs to change and what this means for consumers society and the energy system itself.
Regional Supply Chains for Decarbonising Steel: Energy Efficiency and Green Premium Mitigation
Jan 2022
Publication
Decarbonised steel enabled by green hydrogen-based iron ore reduction and renewable electricity-based steel making will disrupt the traditional supply chain. Focusing on the energetic and techno-economic assessment of potential green supply chains this study investigates the direct reduced iron-electric arc furnace production route enabled by renewable energy and deployed in regional settings. The hypothesis that co-locating manufacturing processes with renewable energy resources would offer highest energy efficiency and cost reduction is tested through an Australia-Japan case study. The binational partnership is structured to meet Japanese steel demand (for domestic use and regional exports) and source both energy and iron ore from the Pilbara region of Western Australia. A total of 12 unique supply chains differentiated by spatial configuration timeline and energy carrier were simulated which validated the hypothesis: direct energy and ore exports to remote steel producers (i.e. Japan-based production) as opposed to co-locating iron and steel production with abundant ore and renewable energy resources (i.e. Australia-based production) increased energy consumption and the levelised cost of steel by 45% and 32% respectively when averaged across 2030 and 2050. Two decades of technological development and economies of scale realisation would be crucial; 2030 supply chains were on average 12% more energy-intense and 23% more expensive than 2050 equivalents. On energy vectors liquefied hydrogen was more efficient than ammonia for export-dominant supply chains due to the pairing of its process flexibility and the intermittent solar energy profile as well as the avoidance of the need for ammonia cracking prior to direct reduction. To mitigate the green premium a carbon tax in the range of A$66–192/t CO2 would be required in 2030 and A$0–70/t CO2 in 2050; the diminished carbon tax requirement in the latter is achievable only by wholly Australia-based production. Further the modelled system scale was immense; producing 40 Mtpa of decarbonised steel will require 74–129% of Australia’s current electricity output and A$137–328 billion in capital investment for solar power production and shipping vessel infrastructure. These results call for strategic planning of regional resource pairing to drive energy and cost efficiencies which accelerate the global decarbonisation of steel.
Feasibility Study into Water Requirement for Hydrogen Production
Nov 2022
Publication
Low carbon hydrogen can be produced by a variety of processes that require substantial quantities of water. Several major hydrogen projects are proposed in Scotland; as an energy storage medium allowing new renewable power capacity to operate and as a direct alternative to displace natural gas as a primary fuel source. The additional water consumption associated with these hydrogen projects presents an infrastructure challenge.
The aims of the study are to evaluate the water requirements of new hydrogen production facilities and the associated implications for water infrastructure and to develop a strategic framework for assessing these aspects of hydrogen projects throughout the UK. The initial focus of the study is on Scotland; however the methodology developed in the project will be used throughout the UK
Benefits
Low carbon hydrogen can be produced by a variety of processes all of which require substantial quantities of water. Several major hydrogen projects are proposed in Scotland; both as an energy storage medium allowing new renewable power capacity (particularly wind) to operate and as a direct alternative to displace natural gas as a primary fuel source. The additional water consumption associated with these hydrogen projects presents an infrastructure challenge e.g. the Scottish Environment Protection Agency (SEPA) recently highlighted Scotland’s vulnerability to dry weather and climate-induced changes in the availability and functioning of water resources.
The project in partnership with Ramboll will look to deliver a technical assessment and feasibility study into water requirements for hydrogen production in Scotland. The aims of the study are to evaluate the water requirements of new hydrogen production facilities and the associated implications for water infrastructure and to develop a strategic framework for assessing these aspects of hydrogen projects throughout the UK. The initial focus of the study is on Scotland; however the methodology developed in the project will be used throughout the UK.
The research paper can be found on their website.
The aims of the study are to evaluate the water requirements of new hydrogen production facilities and the associated implications for water infrastructure and to develop a strategic framework for assessing these aspects of hydrogen projects throughout the UK. The initial focus of the study is on Scotland; however the methodology developed in the project will be used throughout the UK
Benefits
Low carbon hydrogen can be produced by a variety of processes all of which require substantial quantities of water. Several major hydrogen projects are proposed in Scotland; both as an energy storage medium allowing new renewable power capacity (particularly wind) to operate and as a direct alternative to displace natural gas as a primary fuel source. The additional water consumption associated with these hydrogen projects presents an infrastructure challenge e.g. the Scottish Environment Protection Agency (SEPA) recently highlighted Scotland’s vulnerability to dry weather and climate-induced changes in the availability and functioning of water resources.
The project in partnership with Ramboll will look to deliver a technical assessment and feasibility study into water requirements for hydrogen production in Scotland. The aims of the study are to evaluate the water requirements of new hydrogen production facilities and the associated implications for water infrastructure and to develop a strategic framework for assessing these aspects of hydrogen projects throughout the UK. The initial focus of the study is on Scotland; however the methodology developed in the project will be used throughout the UK.
The research paper can be found on their website.
Literature Review on Life Cycle Assessment of Transportation Alternative Fuels
Aug 2023
Publication
Environmental concerns such as global warming and human health damage are intensifying and the transportation sector significantly contributes to carbon and harmful emissions. This review examines the life cycle assessment (LCA) of alternative fuels (AF) evaluating current research on fuel types LCA framework development life cycle inventory (LCI) and impact selection. The objectives of this paper are: (1) to compare various AF LCA frameworks and develop a comprehensive framework for the transportation sector; (2) to identify emission hotspots of different AFs through simulations and real-world cases; (3) to review AF LCA research; (4) to extract valuable information for potential future research directions. The analysis reveals that all stages except for hydrogen use have an environmental impact. LCA boundaries and LCIs vary considerably depending on the raw materials production processes and products involved leading to different emission hotspots. Due to knowledge or data limitations some stages remain uncalculated in the current study emphasizing the need for further refinement of the AF LCI. Future research should also explore the various impacts of widespread adoption of alternative fuels in transportation encompassing social economic and environmental aspects. Lastly the review provides structured recommendations for future research directions.
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.
Review of Sampling and Analysis of Particulate Matter in Hydrogen Fuel
Sep 2023
Publication
This review presents state-of-the-art for representative sampling of hydrogen from hydrogen refueling stations. Documented sampling strategies are presented as well as examples of commercially available equipment for sampling at the hydrogen refueling nozzle. Filter media used for sampling is listed and the performance of some of the filters evaluated. It was found that the filtration efficiency of 0.2 and 5 mm filters were not significantly different when exposed to 200 and 300 nm particles. Several procedures for gravimetric analysis are presented and some of the challenges are identified to be filter degradation pinhole formation and conditioning of the filter prior to measurement. Lack of standardization of procedures was identified as a limitation for result comparison. Finally the review summarizes results including particulate concentration in hydrogen fuel quality data published. It was found that less than 10% of the samples were in violation with the tolerance limit.
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.
Clean Hydrogen Roadmap: Is Greater Realism Leading to more Credible Paths Forward?
Sep 2023
Publication
"The Oxford Institute for Energy Studies started researching the role of hydrogen in the energy transition in 2020. Since then the interest in hydrogen has continued to grow globally across the energy industry. A key research question has been the extent to which clean hydrogen can be scaled up at reasonable cost and whether it can play a significant role in the global energy system. In April 2022 OIES launched a new Hydrogen Research Programme under the overarching theme of ’building business cases for a hydrogen economy’. This overarching theme was selected based on the observation that most clean hydrogen developments to date had been relatively small-scale pilot or demonstration projects typically funded by government grants or subsidies. For clean hydrogen to play a significant role there will need to be business cases developed in order to attract the many hundreds of billions of dollars of investment required most of which will need to come from the private sector albeit ultimately underpinned by government-backed decarbonisation policies. Just over a year has passed since the start of the Hydrogen Research Programme and the intention of this paper is to pull together key themes which have emerged from the research so far and which can form a useful framework for further research both by OIES and others.<br/>The six key themes in this paper listed below are intended to create a framework to at least start to address the challenges:<br/>Hydrogen is in competition with other decarbonisation alternatives.<br/>The business case for clean hydrogen relies on government policy to drive decarbonisation.<br/>It is essential to understand emissions associated with potential hydrogen investments.<br/>Hydrogen investments need to consider the full value chain and its geopolitics.<br/>Transport of hydrogen is expensive and so should be minimised.<br/>Storage of hydrogen is an essential part of the value chain and requires more focus.
Industrial Boilers: Study to Develop Cost and Stock Assumptions for Options to Enable or Require Hydrogen-ready Industrial Boilers
Dec 2022
Publication
This study aims to help the Department for Business Energy and Industrial Strategy (BEIS) determine whether the government should intervene to enable or require hydrogen-ready industrial boiler equipment. It will do this based on information from existing literature along with qualitative and quantitative information from stakeholder engagement. The study draws on evidence gathered through BEIS’ Call for Evidence (CfE) on hydrogen-ready industrial boilers. The assessment will advance the overall understanding of hydrogen-ready industrial boilers based on four outputs: definitions of hydrogen-readiness comparisons of the cost and resource requirement to install and convert hydrogen-ready industrial boiler equipment supply chain capacity for conversion to hydrogen and estimates of the UK industrial boiler population.
Development of a Hydrogen Supplement for use with IGEM/SR/25
Nov 2022
Publication
In response to the UK Government’s commitment to achieve net-zero carbon emissions by 2050 a range of research and demonstration projects are underway to investigate the feasibility of using hydrogen in place of natural gas within the national transmission and distribution system. In order for these projects to achieve their full scope of work a mechanism for performing hazardous area classification for hydrogen installations is required. At present IGEM/SR/25 is used to undertake such assessments for natural gas installations but the standard is not currently applicable to hydrogen or hydrogen/natural gas blends.<br/>This report presents updated data and a summary of the recommended methodologies for hazardous area classification of installations using hydrogen or blends of up to 20% hydrogen in natural gas. The contents of this report are intended to provide a technical commentary and the data for a hydrogen-specific supplement to IGEM/SR/25. The supplement will specifically cover 100% hydrogen and a 20/80% by volume blend of hydrogen/natural gas. Reference to intermediate blends is included in this report where appropriate to cover the anticipated step-wise introduction of hydrogen into the natural gas network.<br/>This report is divided into a series of appendices each of which covers a specific area of the IGEM standard. Each appendix includes a summary of specific recommendations made to enable IGEM/SR/25 to be applied to hydrogen and blends of up to 20% hydrogen in natural gas. The reader is encouraged to review the individual appendices for specific conclusions associated with the topic areas addressed in this report.<br/>In general the existing methodologies and approaches used for area classification in IGEM/SR/25 have been deemed appropriate for installations using either hydrogen or blends of up to 20% hydrogen in natural gas. Where necessary revised versions of the equations and zoning distances used in the standard are presented which account for the influence of material property differences between natural gas and the two alternative fuels considered in this work.
Decarbonisation of Heat and the Role of ‘Green Gas’ in the United Kingdom
May 2018
Publication
This paper looks at the possible role of ‘green gas’ in the decarbonisation of heat in the United Kingdom. The option is under active discussion at the moment because of the UK’s rigorous carbon reduction targets and the growing realisation that there are problems with the ‘default’ option of electrifying heat. Green gas appears to be technically and economically feasible. However as the paper discusses there are major practical and policy obstacles which make it unlikely that the government will commit itself to developing ‘green gas’ in the foreseeable future.
Coupling Green Hydrogen Production to Community Benefits: A Pathway to Social Acceptance?
Feb 2024
Publication
Hydrogen energy technologies are forecasted to play a critical supporting role in global decarbonisation efforts as reflected by the growth of national hydrogen energy strategies in recent years. Notably the UK government published its Hydrogen Strategy in August 2021 to support decarbonisation targets and energy security ambitions. While establishing techno-economic feasibility for hydrogen energy systems is a prerequisite of the prospective transition social acceptability is also needed to support visions for the ‘hydrogen economy’. However to date societal factors are yet to be embedded into policy prescriptions. Securing social acceptance is especially critical in the context of ‘hydrogen homes’ which entails replacing natural gas boilers and hobs with low-carbon hydrogen appliances. Reflecting the nascency of hydrogen heating and cooking technologies the dynamics of social acceptance are yet to be explored in a comprehensive way. Similarly public perceptions of the hydrogen economy and emerging national strategies remain poorly understood. Given the paucity of conceptual and empirical insights this study develops an integrated acceptance framework and tests its predictive power using partial least squares structural equation modelling. Results highlight the importance of risk perceptions trust dynamics and emotions in shaping consumer perceptions. Foremost prospects for deploying hydrogen homes at scale may rest with coupling renewable-based hydrogen production to local environmental and socio-economic benefits. Policy prescriptions should embed societal factors into the technological pursuit of large-scale sustainable energy solutions to support socially acceptable transition pathways.
An Overview of Application-orientated Multifunctional Large-scale Stationary Battery and Hydrogen Hybrid Energy Storage System
Dec 2023
Publication
The imperative to address traditional energy crises and environmental concerns has accelerated the need for energy structure transformation. However the variable nature of renewable energy poses challenges in meeting complex practical energy requirements. To address this issue the construction of a multifunctional large-scale stationary energy storage system is considered an effective solution. This paper critically examines the battery and hydrogen hybrid energy storage systems. Both technologies face limitations hindering them from fully meeting future energy storage needs such as large storage capacity in limited space frequent storage with rapid response and continuous storage without loss. Batteries with their rapid response (90%) excel in frequent short-duration energy storage. However limitations such as a selfdischarge rate (>1%) and capacity loss (~20%) restrict their use for long-duration energy storage. Hydrogen as a potential energy carrier is suitable for large-scale long-duration energy storage due to its high energy density steady state and low loss. Nevertheless it is less efficient for frequent energy storage due to its low storage efficiency (~50%). Ongoing research suggests that a battery and hydrogen hybrid energy storage system could combine the strengths of both technologies to meet the growing demand for large-scale long-duration energy storage. To assess their applied potentials this paper provides a detailed analysis of the research status of both energy storage technologies using proposed key performance indices. Additionally application-oriented future directions and challenges of the battery and hydrogen hybrid energy storage system are outlined from multiple perspectives offering guidance for the development of advanced energy storage systems.
Review on the Thermal Neutrality of Application-orientated Liquid Organic Hydrogen Carrier for Hydrogen Energy Storage and Delivery
Aug 2023
Publication
The depletion and overuse of fossil fuels present formidable challenge to energy supply system and environment. The human society is in great need of clean renewable and sustainable energy which can guarantee the long-term utilization without leading to escalation of greenhouse effect. Hydrogen as an extraordinary secondary energy is capable of realizing the target of environmental protection and transferring the intermittent primary energy to the application terminal while its nature of low volumetric energy density and volatility need suitable storage method and proper carrier. In this context liquid organic hydrogen carrier (LOHC) among a series of storage methods such as compressed and liquefied hydrogen provokes a considerable amount of research interest since it is proven to be a suitable carrier for hydrogen with safety and stability. However the dehydrogenation of hydrogen-rich LOHC materials is an endothermic process and needs large energy consumption which hampers the scale up of the LOHC system. The heat issue is thus essential to be addressed for fulfilling the potential of LOHC. In this work several strategies of heat intensification and management for LOHC system including the microwave irradiation circulation of exhaust heat and direct LOHC fuel cell are summarized and analyzed to provide suggestions and directions for future research.
Knock Mitigation and Power Enhancement of Hydrogen Spark-Ignition Engine through Ammonia Blending
Jun 2023
Publication
Hydrogen and ammonia are primary carbon-free fuels that have massive production potential. In regard to their flame properties these two fuels largely represent the two extremes among all fuels. The extremely fast flame speed of hydrogen can lead to an easy deflagration-to-detonation transition and cause detonation-type engine knock that limits the global equivalence ratio and consequently the engine power. The very low flame speed and reactivity of ammonia can lead to a low heat release rate and cause difficulty in ignition and ammonia slip. Adding ammonia into hydrogen can effectively modulate flame speed and hence the heat release rate which in turn mitigates engine knock and retains the zero-carbon nature of the system. However a key issue that remains unclear is the blending ratio of NH3 that provides the desired heat release rate emission level and engine power. In the present work a 3D computational combustion study is conducted to search for the optimal hydrogen/ammonia mixture that is knock-free and meanwhile allows sufficient power in a typical spark-ignition engine configuration. Parametric studies with varying global equivalence ratios and hydrogen/ammonia blends are conducted. The results show that with added ammonia engine knock can be avoided even under stoichiometric operating conditions. Due to the increased global equivalence ratio and added ammonia the energy content of trapped charge as well as work output per cycle is increased. About 90% of the work output of a pure gasoline engine under the same conditions can be reached by hydrogen/ammonia blends. The work shows great potential of blended fuel or hydrogen/ammonia dual fuel in high-speed SI engines.
Geomechanics of Hydrogen Storage in a Depleted Gas Field
Feb 2024
Publication
We perform a simulation study of hydrogen injection in a depleted gas reservoir to assess the geomechanical impact of hydrogen storage relative to other commonly injected gases (methane CO2). A key finding is that the differences in hydrogen density compressibility viscosity and thermal properties compared to the other gases result in significantly less thermal perturbation at reservoir level. The risks of fault reactivation and wellbore fractures due to thermally-induced stress changes are significantly lower when storing hydrogen compared to results observed in CO2 scenarios. This implies that hydrogen injection and production has a much smaller geomechanical footprint with benefits for operational safety. We also find that use of nitrogen cushion gas ensures efficient deliverability and phase separation in the reservoir. However in this study a large fraction of cushion gas was back-produced in each cycle demonstrating the need for further studies of the surface processing requirements and economic implications.
Geochemical Effects on Storage Gases and Reservoir Rock during Underground Hydrogen Storage: A Depleted North Sea Oil Reservoir Case Study
May 2023
Publication
In this work geochemical modelling using PhreeqC was carried out to evaluate the effects of geochemical reactions on the performance of underground hydrogen storage (UHS). Equilibrium exchange and mineral reactions were considered in the model. Moreover reaction kinetics were considered to evaluate the geochemical effect on underground hydrogen storage over an extended period of 30 years. The developed model was first validated against experimental data adopted from the published literature by comparing the modelling and literature values of H2 and CO2 solubility in water at varying conditions. Furthermore the effects of pressure temperature salinity and CO2% on the H2 and CO2 inventory and rock properties in a typical sandstone reservoir were evaluated over 30 years. Results show that H2 loss over 30 years is negligible (maximum 2%) through the studied range of conditions. The relative loss of CO2 is much more pronounced compared to H2 gas with losses of up to 72%. Therefore the role of CO2 as a cushion gas will be affected by the CO2 gas losses as time passes. Hence remedial CO2 gas injections should be considered to maintain the reservoir pressure throughout the injection and withdrawal processes. Moreover the relative volume of CO2 increases with the increase in temperature and decrease in pressure. Furthermore the reservoir rock properties porosity and permeability are affected by the underground hydrogen storage process and more specifically by the presence of CO2 gas. CO2 dissolves carbonate minerals inside the reservoir rock causing an increase in the rock’s porosity and permeability. Consequently the rock’s gas storage capacity and flow properties are enhanced
Lifetime Greenhouse Gas Emissions from Offshore Hydrogen Production
Aug 2023
Publication
With a limited global carbon budget it is imperative that decarbonisation decisions are based on accurate holistic accounts of all greenhouse gas (GHG) emissions produced to assess their validity. Here the upstream GHG emissions of potential UK offshore Green and Blue hydrogen production are compared to GHG emissions from hydrogen produced through electrolysis using UK national grid electricity and the ‘business-as-usual’ case of continuing to combust methane. Based on an operational life of 25 years and producing 0.5MtH2 per year for each hydrogen process the results show that Blue hydrogen will emit between 200-262MtCO2e of GHG emissions depending on the carbon capture rates achieved (39%–90%) Green hydrogen produced via electrolysis using 100% renewable electricity from offshore wind will emit 20MtCO2e and hydrogen produced via electrolysis powered by the National Grid will emit between 103-168MtCO2e depending of the success of its NetZero strategy. The ‘business-as-usual’ case of continuing to combust methane releases 250MtCO2e over the same lifetime. This study finds that Blue hydrogen at scale is not compatible with the Paris Agreement reduces energy security and will require a substantial GHG emissions investment which excludes it from being a ‘low carbon technology’ and should not be considered for any decarbonisation strategies going forward.
Optimizing the Operational Efficiency of the Underground Hydrogen Storage Scheme in a Deep North Sea Aquifer through Compositional Simulations
Aug 2023
Publication
In this study we evaluate the technical viability of storing hydrogen in a deep UKCS aquifer formation through a series of numerical simulations utilising the compositional simulator CMG-GEM. Effects of various operational parameters such as injection and production rates number and length of storage cycles and shut-in periods on the performance of the underground hydrogen storage (UHS) process are investigated in this study. Results indicate that higher H2 operational rates degrade both the aquifer's working capacity and H2 recovery during the withdrawal phase. This can be attributed to the dominant viscous forces at higher rates which lead to H2 viscous fingering and gas gravity override of the native aquifer water resulting in an unstable displacement of water by the H2 gas. Furthermore analysis of simulation results shows that longer and less frequent storage cycles lead to higher storage capacity and decreased H2 retrieval. We conclude that UHS in the studied aquifer is technically feasible however a thorough evaluation of the operational parameters is necessary to optimise both storage capacity and H2 recovery efficiency.
Hydrogen Production, Storage, Utilisation and Environmental Impacts: A Review
Oct 2021
Publication
Dihydrogen (H2) commonly named ‘hydrogen’ is increasingly recognised as a clean and reliable energy vector for decarbonisation and defossilisation by various sectors. The global hydrogen demand is projected to increase from 70 million tonnes in 2019 to 120 million tonnes by 2024. Hydrogen development should also meet the seventh goal of ‘affordable and clean energy’ of the United Nations. Here we review hydrogen production and life cycle analysis hydrogen geological storage and hydrogen utilisation. Hydrogen is produced by water electrolysis steam methane reforming methane pyrolysis and coal gasification. We compare the environmental impact of hydrogen production routes by life cycle analysis. Hydrogen is used in power systems transportation hydrocarbon and ammonia production and metallugical industries. Overall combining electrolysis-generated hydrogen with hydrogen storage in underground porous media such as geological reservoirs and salt caverns is well suited for shifting excess of-peak energy to meet dispatchable on-peak demand.
Potential Cost Savings of Large-scale Blue Hydrogen Production via Sorption-enhanced Steam Reforming Process
Jan 2024
Publication
As countries work towards achieving net-zero emissions the need for cleaner fuels has become increasingly urgent. Hydrogen produced from fossil fuels with carbon capture and storage (blue hydrogen) has the potential to play a significant role in the transition to a low-carbon economy. This study examined the technical and economic potential of blue hydrogen produced at 600 MWth(LHV) and scaled up to 1000 MWth(LHV) by benchmarking sorption-enhanced steam reforming process against steam methane reforming (SMR) autothermal gasheated reforming (ATR-GHR) integrated with carbon capture and storage (CCS) and SMR with CCS. Aspen Plus® was used to develop the process model which was validated using literature data. Cost sensitivity analyses were also performed on two key indicators: levelised cost of hydrogen and CO2 avoidance cost by varying natural gas price electricity price CO2 transport and storage cost and carbon price. Results indicate that at a carbon price of 83 £/tCO2e the LCOH for SE-SR of methane is the lowest at 2.85 £/kgH2 which is 12.58% and 22.55% lower than that of ATR-GHR with CCS and SMR plant with CCS respectively. The LCOH of ATR-GHR with CCS and SMR plant with CCS was estimated to be 3.26 and 3.68 £/kgH2 respectively. The CO2 avoidance cost was also observed to be lowest for SE-SR followed by ATR-GHR with CCS then SMR plant with CCS and was observed to reduce as the plant scaled to 1000 MWth(LHV) for these technologies.
Natural Hydrogen in the Energy Transition: Fundamentals, Promise, and Enigmas
Oct 2023
Publication
Beyond its role as an energy vector a growing number of natural hydrogen sources and reservoirs are being discovered all over the globe which could represent a clean energy source. Although the hydrogen amounts in reservoirs are uncertain they could be vast and they could help decarbonize energy-intensive economic sectors and facilitate the energy transition. Natural hydrogen is mainly produced through a geochemical process known as serpentinization which involves the reaction of water with low-silica ferrous minerals. In favorable locations the hydrogen produced can become trapped by impermeable rocks on its way to the atmosphere forming a reservoir. The safe exploitation of numerous natural hydrogen reservoirs seems feasible with current technology and several demonstration plants are being commissioned. Natural hydrogen may show variable composition and require custom separation purification storage and distribution facilities depending on the location and intended use. By investing in research in the mid-term more hydrogen sources could become exploitable and geochemical processes could be artificially stimulated in new locations. In the long term it may be possible to leverage or engineer the interplay between microorganisms and geological substrates to obtain hydrogen and other chemicals in a sustainable manner.
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