United Kingdom
Heating Economics Evaluated Against Emissions: An Analysis of Low-carbon Heating Systems with Spatiotemporal and Dwelling Variations
Oct 2022
Publication
An understanding of heating technologies from the consumers’ perspective is critical to ensure low-carbon technologies are adopted for reducing their current associated emissions. Existing studies from the consumers’ perspective do not compare and optimise the full range and combinations of potential heating systems. There is also little consideration of how spatiotemporal and dwelling variations combined alter the economic and environmental effectiveness of technologies. The novelty of this paper is the creation and use of a new comprehensive framework to capture the range of heating technologies and their viability for any specific dwelling’s traits and climate from customers’ perspective which is missing from current studies. The model optimises combinations of prime heaters energy sources ancillary solar technologies and sizes thermal energy storage sizes and tariffs with hourly heating simulation across a year and compares their operation capital and lifetime costs alongside emissions to realise the true preferential heating systems for customers which could be used by various stakeholders. Using the UK as a case study the results show electrified heating is generally the optimum lifetime cost solution mainly from air source heat pumps coupled with photovoltaics. However direct electrical heating becomes more economically viable as dwelling demands reduce from smaller dwellings or warmer climates as shorter durations of the ownership are considered or with capital cost constraints from lower income households. Understanding this is of high importance as without correctly targeted incentives a larger uptake of direct electrical heating may occur which will burden the electrical network and generation to a greater extent than more efficient heat pumps.
Next for Net Zero Podcast: Unlock & Understand, Achieving a More Sustainable Future
Sep 2022
Publication
This episode examines how we are tackling a sustainable future – with Net Zero hurtling towards us at great pace. We’re around a year on from the pledges made at COP26 the UK’s Green Recovery initiative is well under way and by next year Britain is aiming to blend up to 20 per cent hydrogen into its gas networks. So now is the time to continue to unlock new insight and understand further the realities of both the challenges and opportunities ahead.
The podcast can be found here.
The podcast can be found here.
Green Ammonia as a Spatial Energy Vector: A Review
May 2021
Publication
Green hydrogen is considered a highly promising vector for deep decarbonisation of energy systems and is forecast to represent 20% of global energy use by 2050. In order to secure access to this resource Japan Germany and South Korea have announced plans to import hydrogen; other major energy consumers are sure to follow. Ammonia a promising hydrogen derivative may enable this energy transport by densifying hydrogen at relatively low cost using well-understood technologies. This review seeks to describe a global green ammonia import/export market: it identifies benefits and limitations of ammonia relative to other hydrogen carriers the costs of ammonia production and transport and the constraints on both supply and demand. We find that green ammonia as an energy vector is likely to be critical to future energy systems but that gaps remain in the literature. In particular rigorous analysis of production and transport costs are rarely paired preventing realistic assessments of the delivered cost of energy or the selection of optimum import/export partners to minimise the delivered cost of ammonia. Filling these gaps in the literature is a prerequisite to the development of robust hydrogen and ammonia strategies and to enable the formation of global import and export markets of green fuel
A Review on Ports' Readiness to Facilitate International Hydrogen Trade
Jan 2023
Publication
The existing literature on the hydrogen supply chains has knowledge gaps. Most studies focus on hydrogen production storage transport and utilisation but neglect ports which are nexuses in the supply chains. To fill the gap this paper focuses on ports' readiness for the upcoming hydrogen international trade. Potential hydrogen exporting and importing ports are screened. Ports' readiness for hydrogen export and import are reviewed from perspectives of infrastructure risk management public acceptance regulations and standards and education and training. The main findings are: (1) liquid hydrogen ammonia methanol and LOHCs are suitable forms for hydrogen international trade; (2) twenty ports are identified that could be first movers; among them twelve are exporting ports and eight are importing ports; (3) ports’ readiness for hydrogen international trade is still in its infancy and the infrastructure construction or renovation risk management measures establishment of regulations and standards education and training all require further efforts.
Technical and Economic Performance Assessment of Blue Hydrogen Production Using New Configuration Through Modelling and Simulation
Mar 2024
Publication
Steam methane reforming (SMR) is the dominant process for hydrogen production which produce large amount of carbon dioxide (CO2) as a by-product. To address concerns about carbon emissions there is an increasing focus on blue hydrogen to mitigate carbon emissions during hydrogen production. However the commercialization of blue hydrogen production (BHP) is hindered by the challenges of high cost and energy consumption. This study proposes a new configuration to address these challenges which is characterized by: (a) the use of piperazine (PZ) as a solvent which has a high CO2 absorption efficiency; (b) a more efficient heat exchange configuration which recovers the waste exergy from flue gas; (c) the advanced flash stripper (AFS) was adopted to reduce the capital cost due to its simpler stripper configuration. In addition the technical and economic performance of the proposed energy and cost-saving blue hydrogen production (ECSB) process is investigated and compared with the standard SMR process. The detailed models of the SMR process and the post-combustion carbon capture (PCC) process were developed and integrated in Aspen plus® V11. The results of the technical analysis showed that the ECSB process with 30 wt.% PZ achieves a 36.3 % reduction in energy penalty when compared to the standard process with 30 wt.% Monoethanolamine (MEA). The results of the economic analysis showed that the lowest levelized cost of blue hydrogen (LCBH) was achieved by the ECSB process with 30 wt.% PZ. Compared to the BHP process with 30 wt.% MEA the LCBH was reduced by 19.7 %.
Gas Goes Green: Britain's Hydrogen Blending Delivery Plan
Jan 2022
Publication
Britain’s Hydrogen Blending Delivery Plan which sets out how all five of Britain’s gas grid companies will meet the Government’s target for Britain’s network of gas pipes to be ready to deliver 20% hydrogen to homes and businesses from 2023 as a replacement for natural gas.
Ammonia: Zero-carbon Fertiliser, Fuel and Energy Storage
Feb 2020
Publication
This briefing considers the opportunities and challenges associated with the manufacture and future use of zero-carbon ammonia which is referred to in this report as green ammonia. The production of green ammonia has the capability to impact the transition towards zero-carbon through the decarbonisation of its current major use in fertiliser production. Perhaps as significantly it has the following potential uses: • As a medium to store and transport chemical energy with the energy being released either by directly reacting with air or by the full or partial decomposition of ammonia to release hydrogen. • As a transport fuel by direct combustion in an engine or through chemical reaction with oxygen in the air in a fuel cell to produce electricity to power a motor. • To store thermal energy through the absorption of water and through phase changes between material states (for example liquid to gas).
Impact of Hydrogen Liquefaction on Hydrogen Fuel Quality for Transport Applications (ISO-14687:2019)
Aug 2022
Publication
Decarbonisation of the energy sector is becoming increasingly more important to the reduction in climate change. Renewable energy is an effective means of reducing CO2 emissions but the fluctuation in demand and production of energy is a limiting factor. Liquid hydrogen allows for long-term storage of energy. Hydrogen quality is important for the safety and efficiency of the end user. Furthermore the quality of the hydrogen gas after liquefaction has not yet been reported. The purity of hydrogen after liquefaction was assessed against the specification of Hydrogen grade D in the ISO-14687:2019 by analysing samples taken at different locations throughout production. Sampling was carried out directly in gas cylinders and purity was assessed using multiple analytical methods. The results indicate that the hydrogen gas produced from liquefaction is of a higher purity than the starting gas with all impurities below the threshold values set in ISO-14687:2019. The amount fraction of water measured in the hydrogen sample increased with repeated sampling from the liquid hydrogen tank suggesting that the sampling system used was affected by low temperatures (−253 ◦C). These data demonstrate for the first time the impact of liquefaction on hydrogen purity assessed against ISO-14687:2019 showing that liquified hydrogen is a viable option for long-term energy storage whilst also improving quality.
The Key Techno-Economic and Manufacturing Drivers for Reducing the Cost of Power-to-Gas and a Hydrogen-Enabled Energy System
Jul 2021
Publication
Water electrolysis is a process which converts electricity into hydrogen and is seen as a key technology in enabling a net-zero compatible energy system. It will enable the scale-up of renewable electricity as a primary energy source for heating transport and industry. However displacing the role currently met by fossil fuels might require a price of hydrogen as low as 1 $/kg whereas renewable hydrogen produced using electrolysis is currently 10 $/kg. This article explores how mass manufacturing of proton exchange membrane (PEM) electrolysers can reduce the capital cost and thus make the production of renewable power to hydrogen gas (PtG) more economically viable. A bottom up direct manufacturing model was developed to determine how economies of scale can reduce the capital cost of electrolysis. The results demonstrated that (assuming an annual production rate of 5000 units of 200 kW PEM electrolysis systems) the capital cost of a PEM electrolysis system can reduce from 1990 $/kW to 590 $/kW based on current technology and then on to 431 $/kW and 300 $/kW based on the an installed capacity scale-up of ten- and one-hundred-fold respectively. A life-cycle costing analysis was then completed to determine the importance of the capital cost of an electrolysis system to the price of hydrogen. It was observed that based on current technology mass manufacturing has a large impact on the price of hydrogen reducing it from 6.40 $/kg (at 10 units units per year) to 4.16 $/kg (at 5000 units per year). Further analysis was undertaken to determine the cost at different installed capacities and found that the cost could reduce further to 2.63 $/kg and 1.37 $/kg based on technology scale-up by ten- and one hundred-fold respectively. Based on the 2030 (and beyond) baseline assumptions it is expected that hydrogen production from PEM electrolysis could be used as an industrial process feed stock provide power and heat to buildings and as a fuel for heavy good vehicles (HGVs). In the cases of retrofitted gas networks for residential or industrial heating solutions or for long distance transport it represents a more economically attractive and mass-scale compatible solution when compared to electrified heating or transport solutions.
Blast Wave Generated by Delayed Ignition of Under-Expanded Hydrogen Free Jet at Ambient and Cryogenic Temperatures
Nov 2022
Publication
An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using available experimental data. The dimensionless blast wave overpressure generated by delayed ignition and the follow-up deflagration or detonation of hydrogen jets at an any location from the jet ∆Pexp/P0 is correlated to the original dimensionless parameter composed of the product of the dimensionless ratio of storage pressure to atmospheric pressure Ps/P0 and the ratio of the jet release nozzle diameter to the distance from the centre of location of the fast-burning near-stoichiometric mixture on the jet axis (30% of hydrogen in the air by volume) to the location of a target (personnel or property) d/Rw. The correlation is built using the analysis of 78 experiments regarding this phenomenon in the wide range of hydrogen storage pressure of 0.5–65.0 MPa and release diameter of 0.5–52.5 mm. The correlation is applicable to hydrogen free jets at ambient and cryogenic temperatures. It is found that the generated blast wave decays inversely proportional to the square of the distance from the fast-burning portion of the jet. The correlation is used to calculate the hazard distances by harm thresholds for five typical hydrogen applications. It is observed that in the case of a vehicle with onboard storage tank at pressure 70 MPa the “no-harm” distance for humans reduces from 10.5 m to 2.6 m when a thermally activated pressure relief device (TPRD) diameter decreases from 2 mm to a diameter of 0.5 mm.
Assessment of Hydrogen Fuel for Rotorcraft Applications
Jun 2022
Publication
This paper presents the application of a multidisciplinary approach for the preliminary design and evaluation of the potential improvements in performance and environmental impact through the utilization of compressed (CGH2) and liquefied (LH2) hydrogen fuel for a civil tilt-rotor modelled after the NASA XV-15. The methodology deployed comprises models for rotorcraft flight dynamics engine performance flight path analysis hydrogen tank and thermal management system sizing. Trade-offs between gravimetric efficiency energy consumption fuel burn CO2 emissions and cost are quantified and compared to the kerosene-fuelled rotorcraft. The analysis carried out suggests that for these vehicle scales gravimetric efficiencies of the order of 13% and 30% can be attained for compressed and liquid hydrogen storage respectively leading to reduced range capability relative to the baseline tilt-rotor by at least 40%. At mission level it is shown that the hydrogen-fuelled configurations result in increased energy consumption by at least 12% (LH2) and 5% (CGH2) but at the same time significantly reduced life-cycle carbon emissions compared to the kerosene counterpart. Although LH2 storage at cryogenic conditions has a higher gravimetric efficiency than CGH2 (at 700 bar) it is shown that for this class of rotorcraft the latter is more energy efficient when the thermal management system for fuel pressurization and heating prior to combustion is accounted for.
Stand-off Detection of Hydrogen Concentration
Sep 2021
Publication
The ability to remotely monitor hydrogen and map its concentration is a pressing challenge in large scale production and distribution as well as other sectors such as nuclear storage. We present a photonicsbased approach for the stand-off sensing and mapping of hydrogen concentration capable of detecting and locating <0.1% concentrations at 100m distance. The technique identifies the wavelength of light resulting from interaction with laser pulses via Raman scattering and can identify a range of other gas species e.g. hydrocarbons ammonia by the spectroscopic analysis of the wavelengths present in the return signal. LIDAR Light Detection and Ranging – analogous to Radar is used for ranging. Laserbased techniques for the stand-off detection of hydrocarbons frequently employ absorption of light at specific wavelengths which are characteristic of the gas species. Unfortunately Hydrogen does not exhibit strong absorption however it does exhibit strong Raman scattering when excited in the UV wavelength range. Raman scattering is a comparatively weak effect. However the use of solid-state detectors capable of detecting single photons known as SPADS (Single Photon Avalanche Photodiode) enables the detection of low concentrations at range while making use of precise time-of-flight range location correlation. The initial safety case which necessitated our development of stand-off hydrogen sensing was the condition monitoring of stored nuclear waste supported and funded by Sellafield and the National Nuclear Laboratory in the UK. A deployable version of the device has been developed and hydrogen characterisation has been carried out in an active nuclear store. Prior to deployment a full ignition risk assessment was carried out. To the best of our knowledge this technique is the strongest candidate for the remote stand-off sensing of hydrogen.
Techno-Economic Analysis of Hydrogen Storage Technologies for Railway Engineering: A Review
Sep 2022
Publication
According to the specific requirements of railway engineering a techno-economic comparison for onboard hydrogen storage technologies is conducted to discuss their feasibility and potentials for hydrogen-powered hybrid trains. Physical storage methods including compressed hydrogen (CH2 ) liquid hydrogen (LH2 ) and cryo-compressed hydrogen (CcH2 ) and material-based (chemical) storage methods such as ammonia liquid organic hydrogen carriages (LOHCs) and metal hydrides are carefully discussed in terms of their operational conditions energy capacity and economic costs. CH2 technology is the most mature now but its storage density cannot reach the final target which is the same problem for intermetallic compounds. In contrast LH2 CcH2 and complex hydrides are attractive for their high storage density. Nevertheless the harsh working conditions of complex hydrides hinder their vehicular application. Ammonia has advantages in energy capacity utilisation efficiency and cost especially being directly utilised by fuel cells. LOHCs are now considered as a potential candidate for hydrogen transport. Simplifying the dehydrogenation process is the important prerequisite for its vehicular employment. Recently increasing novel hydrogen-powered trains based on different hydrogen storage routes are being tested and optimised across the world. It can be forecasted that hydrogen energy will be a significant booster to railway decarbonisation.
Stochastic Low-order Modelling of Hydrogen Autoignition in a Turbulent Non-premixed Flow
Jul 2022
Publication
Autoignition risk in initially non-premixed flowing systems such as premixing ducts must be assessed to help the development of low-NOx systems and hydrogen combustors. Such situations may involve randomly fluctuating inlet conditions that are challenging to model in conventional mixture-fraction-based approaches. A Computational Fluid Dynamics (CFD)-based surrogate modelling strategy is presented here for fast and accurate predictions of the stochastic autoignition behaviour of a hydrogen flow in a hot air turbulent co-flow. The variability of three input parameters i.e. inlet fuel and air temperatures and average wall temperature is first sampled via a space-filling design. For each sampled set of conditions the CFD modelling of the flame is performed via the Incompletely Stirred Reactor Network (ISRN) approach which solves the reacting flow governing equations in post-processing on top of a Large Eddy Simulation (LES) of the inert hydrogen plume. An accurate surrogate model namely a Gaussian Process is then trained on the ISRN simulations of the burner and the final quantification of the variability of autoignition locations is achieved by querying the surrogate model via Monte Carlo sampling of the random input quantities. The results are in agreement with the observed statistics of the autoignition locations. The methodology adopted in this work can be used effectively to quantify the impact of fluctuations and assist the design of practical combustion systems. © 2022 The Authors. Published by Elsevier Inc. on behalf of The Combustion Institute.
Beyond the triangle of renewable Energy Acceptance: The Five Dimensions of Domestic Hydrogen Acceptance
Aug 2022
Publication
The ‘deep’ decarbonization of the residential sector is a priority for meeting national climate change targets especially in countries such as the UK where natural gas has been the dominant fuel source for over half a century. Hydrogen blending and repurposing the national grid to supply low-carbon hydrogen gas may offer respective short- and long-term solutions to achieving emissions reduction across parts of the housing sector. Despite this imperative the social acceptance of domestic hydrogen energy technologies remains underexplored by sustainability scholars with limited insights regarding consumer perceptions and expectations of the transition. A knowledge deficit of this magnitude is likely to hinder effective policymaking and may result in sub-optimal rollout strategies that derail the trajectory of the net zero agenda. Addressing this knowledge gap this study develops a conceptual framework for examining the consumer-facing side of the hydrogen transition. The paper affirms that the spatiotemporal patterns of renewable energy adoption are shaped by a range of interacting scales dimensions and factors. The UK’s emerging hydrogen landscape and its actor-network is characterized as a heterogenous system composed of dynamic relationships and interdependencies. Future studies should engage with domestic hydrogen acceptance as a co-evolving multi-scalar phenomenon rooted in the interplay of five distinct dimensions: attitudinal socio-political community market and behavioral acceptance. If arrived to behavioral acceptance helps realize the domestication of hydrogen heating and cooking established on grounds on cognitive sociopolitical and sociocultural legitimacy. The research community should internalize the complexity and richness of consumer attitudes and responses through a more critical and reflexive approach to the study of social acceptance.
Techno-economic Assessment of Offshore Wind-to-hydrogen Scenarios: A UK Case Study
Jan 2023
Publication
The installed capacity electricity generation from wind and the curtailment of wind power in the UK between 2011 and 2021 showed that penetration levels of wind energy and the amount of energy that is curtailed in future would continue to rise whereas the curtailed energy could be utilised to produce green hydrogen. In this study data were collected technologies were chosen systems were designed and simulation models were developed to determine technical requirements and levelised costs of hydrogen produced and transported through different pathways. The analysis of capital and operating costs of the main components used for onshore and offshore green hydrogen production using offshore wind including alternative strategies for hydrogen storage and transport and hydrogen carriers showed that a significant reduction in cost could be achieved by 2030 enabling the production of green hydrogen from offshore wind at a competitive cost compared to grey and blue hydrogen. Among all scenarios investigated in this study compressed hydrogen produced offshore is the most cost-effective scenario for projects starting in 2025 although the economic feasibility of this scenario is strongly affected by the storage period and the distance to the shore of the offshore wind farm. Alternative scenarios for hydrogen storage and transport such as liquefied hydrogen and methylcyclohexane could become more cost-effective for projects starting in 2050 when the levelised cost of hydrogen could reach values of about £2 per kilogram of hydrogen or lower.
Life Cycle Cost Analysis of an Autonomous Underwater Vehicle that Employs Hydrogen Fuel Cell
Feb 2024
Publication
The use of autonomous vehicles for marine and submarine work has risen considerably in the last decade. Developing new monitoring systems navigation and communications technologies allows a wide range of operational possibilities. Autonomous Underwater Vehicles (AUVs) are being used in offshore missions and applications with some innovative purposes by using sustainable and green energy sources. This paper considers an AUV that uses a hydrogen fuel cell achieving zero emissions. This paper analyses the life cycle cost of the UAV and compares it with a UAV powered by conventional energy. The EN 60300-3-3 guidelines have been employed to develop the cost models. The output results show estimations for the net present value under different scenarios and financial strategies. The study has been completed with the discount rate sensibility analysis in terms of financial viability.
Socio-technical Barriers to Domestic Hydrogen Futures: Repurposing Pipelines, Policies, and Public Perceptions
Feb 2023
Publication
The feasibility of the global energy transition may rest on the ability of nations to harness hydrogen's potential for cross-sectoral decarbonization. In countries historically reliant on natural gas for domestic heating and cooking such as the UK hydrogen may prove critical to meeting net-zero targets and strengthening energy security. In response the UK government is targeting industrial decarbonization via hydrogen with parallel interest in deploying hydrogen-fueled appliances for businesses and homes. However prospective hydrogen futures and especially the domestic hydrogen transition face multiple barriers which reflect the cross-sectoral dynamics of achieving economies of scale and social acceptance. Addressing these challenges calls for a deep understanding of socio-technical factors across different scales of the hydrogen economy. In response this paper develops a socio-technical systems framework for overcoming barriers to the domestic transition which is applied to the UK context. The paper demonstrates that future strategies should account for interactions between political techno-economic technical market and social dimensions of the hydrogen transition. In parallel to techno-economic feasibility the right policies will be needed to create an even playing field for green hydrogen technologies while also supporting stakeholder symbiosis and consumer buy-in. Future studies should grapple with how an effective repurposing of pipelines policies and public perceptions can be aligned to accelerate the development of the hydrogen economy with maximum net benefits for society and the environment.
Next for Net Zero Podcast: Transporting to a Greener World
Oct 2022
Publication
Decarbonisation will need a significant societal shift. The when why and how we travel is going to look very different within a decade. Joining us is Florentine Roy – a leading expert on electric vehicles and Innovation Project Lead at UK Power Networks and Matt Hindle - Head of Net Zero and Sustainability at Wales and West Utilities. Let’s talk about the energy system implications of this massive undertaking and how it can be enabled by innovation in a fair and just way.
The podcast can be found here.
The podcast can be found here.
Notes on the Development of the Hydrogen Supplement to IGEM/TD13 > 7 bar
Nov 2021
Publication
IGEM/TD/13 Standard applies to the safe design construction inspection testing operation and maintenance of pressure regulating installations (PRIs) in accordance with current knowledge and operational experience.
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations:
This Supplement provides additional requirements for new PRIs to be used for the transmission of Hydrogen including Natural Gas/Hydrogen blended mixtures (subsequently referred to as NG/H blends) and for the repurposing of Natural Gas (NG) PRIs for Hydrogen service.
NG/H blends are considered to be equivalent to 100 mol % Hydrogen with respect to limits on design stresses the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials.
NG/H blends containing in excess of 10 mol % Hydrogen are considered to be equivalent to 100 mol.% Hydrogen with respect to all other requirements except for hazardous areas.
This Supplement gives additional recommendations for PRIs and installations:
- with an upstream maximum operating pressure (MOP) not greater than 100 bar
- with an outlet pressure greater than or equal to 7 bar
- for use with Hydrogen or NG/H blends with a Hydrogen content greater than 10 %
- operating with a temperature range between -20°C and 120°C.
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