Publications

The strategic importance of hydrogen has gained significant recognition as nations across the world have committed to achieving net zero. Here in the UK there’s a widespread consensus that hydrogen is critical to achieving our net zero target. This commitment culminated in the launch of the UK’s first Hydrogen Strategy and has been reaffirmed by Chris Skidmore’s Independent Review of Net Zero. Both these documents highlight hydrogen’s importance not only to net zero but growing the UK industrial base1 . Analysis by Hydrogen UK estimates up to 20000 jobs could be created by 2030 contributing £26bn in cumulative GVA2. These economic benefits flow from all areas of the value chain ranging from production storage network development and off-taker markets. However with large scale projects still to take final investment decisions current volumes of low-carbon hydrogen produced and consumed fall well below the government’s 2030 ambitions. Encouragingly the UK has a positive track record of deploying low carbon technologies. The combination of the UK’s world leading policies and incentive schemes alongside our vibrant RD&I and engineering environment has enabled rapid deployment of technologies like offshore wind and electric vehicles. Yet despite being world leaders in deployment early opportunities for regional supply chain growth and job creation were not fully realised and taken advantage of from inception. The hydrogen sector is therefore at a tipping point. To capitalise on the economic opportunity hydrogen offers the UK must learn from prior technology deployments and build a strong domestic hydrogen supply chain in parallel to championing deployment. This report delivers on a recommendation from the Hydrogen Champion Report which encouraged industry to create an industry led supply chain strategy3 . With Hydrogen UK steering the work on behalf of the UK hydrogen industry this study focusses on identifying the actions needed to mature a local supply chain that can support the initial deployment of hydrogen technologies across the value chain. The report is segmented into two sections. The first section outlines a voluntary ambition for local content from industry alongside the potential intervention mechanisms needed to achieve the ambition. The second section exploresthe challenges companies across the hydrogen value chain face in maximising UK supply chain opportunities.

This report can be found on Hydrogen UK's website.

Hydrogen is one of the most popular alternatives for energy storage. Because of its low volumetric energy density hydrogen should be compressed for practical storage and transportation purposes. Recently electrochemical hydrogen compressors (EHCs) have been developed that are capable of compressing hydrogen up to P = 1000 bar and have the potential of reducing compression costs to 3 kWh/kg. As EHC compressed hydrogen is saturated with water the maximum water content in gaseous hydrogen should meet the fuel requirements issued by the International Organization for Standardization (ISO) when refuelling fuel cell electric vehicles. The ISO 14687−2:2012 standard has limited the water concentration in hydrogen gas to 5 μmol water per mol hydrogen fuel mixture. Knowledge on the vapor liquid equilibrium of H2O−H2 mixtures is crucial for designing a method to remove H2O from compressed H2. To the best of our knowledge the only experimental high pressure data (P > 300 bar) for the H2O−H2 phase coexistence is from 1927 [J. Am. Chem. Soc. 1927 49 65−78]. In this paper we have used molecular simulation and thermodynamic modeling to study the phase coexistence of the H2O−H2 system for temperatures between T = 283 K and T = 423 K and pressures between P = 10 bar and P = 1000 bar. It is shown that the Peng-Robinson equation of state and the Soave Redlich-Kwong equation of state with van der Waals mixing rules fail to accurately predict the equilibrium coexistence compositions of the liquid and gas phase with or without fitted binary interaction parameters. We have shown that the solubility of water in compressed hydrogen is adequately predicted using force-field-based molecular simulations. The modeling of phase coexistence of H2O−H2 mixtures will be improved by using polarizable models for water. In the Supporting Information we present a detailed overview of available experimental vapor−liquid equilibrium and solubility data for the H2O−H2 system at high pressures.

The concept of the “hydrogen economy” was first coined by Prof. John Bockris during a talk he gave in 1970 at the General Motors Technical Center. Bockris’s talk introduced the vision of a world economy in which energy was carried in the form of hydrogen resulting in zero emissions at its point of use—be that as a chemical feedstock or as a fuel for industrial or domestic heating for power generation in a gas turbine or in a fuel cell “engine” for transport applications. Despite several waves of significant interest and investment however due to the relative costs and technological immaturity of hydrogen technologies the hydrogen economy was never delivered at scale nor was there sufficient motivation to create the technology needed to overcome these hurdles.<br/>But today as the world seeks to transition to a truly net-zero carbon economy hydrogen has returned to the fore as a key energy carrier—not as a hydrogen economy but as “hydrogen in the economy” synergistically working alongside low- to zero-carbon electricity to decarbonize those parts of the economy that are too expensive or too difficult to be directly decarbonized with electricity. These include:<br/>♦ Transport applications in which large amounts of energy are needed on the vehicle such as planes trains shipping long-distance trucks and heavy-duty vehicles;<br/>♦ Industrial applications such as steelmaking and cement manufacturing;<br/>♦ Long-term energy storage for days to weeks at a time;<br/>♦ The production of green chemicals such as green ammonia and green methanol;<br/>♦ Industrial (and potentially residential) heating.

Japan has formulated a net-zero emissions target by 2050. Existing scenarios consistent with this target generally depend on carbon dioxide removal (CDR). In addition to domestic mitigation actions the import of low-carbon energy carriers such as hydrogen and synfuels and negative emissions credits are alternative options for achieving net-zero emissions in Japan. Although the potential and costs of these actions depend on global energy system transition characteristics which can potentially be informed by the global integrated assessment models they are not considered in current national scenario assessments. This study explores diverse options for achieving Japan's net-zero emissions target by 2050 using a national energy system model informed by international energy trade and emission credits costs estimated with a global energy system model. We found that demand-side electrification and approximately 100 Mt-CO2 per year of CDR implementation equivalent to approximately 10% of the current national CO2 emissions are essential across all net-zero emissions scenarios. Upscaling of domestically generated hydrogen-based alternative fuels and energy demand reduction can avoid further reliance on CDR. While imports of hydrogen-based energy carriers and emission credits are effective options annual import costs exceed the current cost of fossil fuel imports. In addition import dependency reaches approximately 50% in the scenario relying on hydrogen imports. This study highlights the importance of considering global trade when developing national net-zero emissions scenarios and describes potential new roles for global models.

Hydrogen has emerged as a critical energy carrier for achieving global decarbonization and supporting a sustainable energy future. This review explores key advancements in hydrogen production technologies including electrolysis biomass gasification and thermochemical processes alongside innovations in storage methods like metal hydrides and liquid organic hydrogen carriers (LOHCs). Despite its promise challenges such as high production costs scalability issues and safety concerns persist. Biomass gasification stands out for its dual benefits of waste management and carbon neutrality yet hurdles like feedstock variability and energy efficiency need further attention. This review also identifies opportunities for improvement such as developing cost-effective catalysts and hybrid storage systems while emphasizing future research on improving storage efficiency and tackling production bottlenecks. By addressing these challenges hydrogen can play a central role in the global transition to cleaner energy systems.

This paper examines the crucial elements of pipeline-based hydrogen transportation highlighting the particular difficulties and technical developments required to guarantee the sustainable effective and safe supply of hydrogen. This study lists the essential phases of hydrogen pipeline management from design to repair as the relevance of hydrogen infrastructure in the worldwide energy transition continues to rise. It discusses the upkeep monitoring operation and rehabilitation procedures for aged pipelines with an emphasis on the cutting-edge techniques and technology used to mitigate the dangers related to hydrogen’s unique features such as leakage and embrittlement. Together with highlighting the legislative and regulatory frameworks that enable the infrastructure this paper also discusses the material economic and environmental difficulties related to hydrogen pipelines. Lastly it emphasizes how crucial it is to fund research create cutting-edge materials and implement sophisticated monitoring systems to guarantee the long-term dependability and safety of hydrogen pipelines. These initiatives will be crucial in allowing hydrogen’s contribution to the future of renewable energy together with international collaboration on regulatory standards.

The work carried out in this paper focused on “Machine learning models for the prediction of turbulent combustion speed for hydrogen-natural gas spark ignition engines”. The aim of this work is to develop and verify the ability of machine learning models to solve the problem of estimating the turbulent flame speed for a spark-ignition internal combustion engine operating with a hydrogen-natural gas mixture then evaluate the relevance of these models in relation to the usual approaches. The novelty of this work is the possibility of a direct calculation of turbulent combustion speed with a good precision using only machine learning model. The obtained models are also compared to each other by considering in turn as a comparison criterion: the precision of the result calculation time and the ability to assimilate original data (which has not undergone preprocessing). An important particularity of this work is that the input variables of the machine learning models were chosen among the variables directly measurable experimentally based on the opinion of experts in combustion in internal combustion engines and not on the usual approaches to dimensionality reduction on a dataset. The data used for this work was taken from a MINSEL 380 a 380-cc single-cylinder engine. The results show that all the machine learning models obtained are significantly faster than the usual approach and Random Forest (R2: R-squared = 0.9939 and RMSE: Root Mean Square Error = 0.4274) gives the best results. With a forecasting accuracy of over 90 % both approaches can make reasonable predictions for most industrial applications such as designing engine monitoring and control systems firefighting systems simulation and prototyping tools.

Reversible solid oxide cells (rSOC) enable the efficient cyclic conversion between electrical and chemical energy in the form of fuels and chemicals thereby providing a pathway for longterm and high-capacity energy storage. Amongst the different fuels under investigation hydrogen methane and ammonia have gained immense attention as carbon-neutral energy vectors. Here we have compared the energy efficiency and the energy demand of rSOC based on these three fuels. In the fuel cell mode of operation (energy generation) two different routes have been considered for both methane and ammonia; Routes 1 and 2 involve internal reforming (in the case of methane) or cracking (in the case of ammonia) and external reforming or cracking respectively. The use of hydrogen as fuel provides the highest round-trip efficiency (62.1%) followed by methane by Route 1 (43.4%) ammonia by Route 2 (41.1%) methane by Route 2 (40.4%) and ammonia by Route 1 (39.2%). The lower efficiency of internal ammonia cracking as opposed to its external counterpart can be attributed to the insufficient catalytic activity and stability of the state-of-the-art fuel electrode materials which is a major hindrance to the scale-up of this technology. A preliminary cost estimate showed that the price of hydrogen methane and ammonia produced in SOEC mode would be ~1.91 3.63 and 0.48 $/kg respectively. In SOFC mode the cost of electricity generation using hydrogen internally reformed methane and internally cracked ammonia would be ~52.34 46.30 and 47.11 $/MWh respectively.

Steam methane reforming (SMR) is a leading technology for hydrogen production. However this technology is still carbon-intensive since in current SMR units the PSA tail gas containing H2 CO and CH4 is burned at the reformer with air and exits the stack at a CO2 purity of less than 5% which is not feasible to capture. In this paper we aim to either harness the energy content of this gas to generate power in a solid oxide fuel cell (SOFC) or burn it via chemical looping combustion (CLC) or oxy-combustion process to produce off-gas with high CO2 purity ready to storage. Therefore an industrial-scale PSA with 72000 Nm3/h feed capacity was modelled to obtain the tail gas flow rate and composition. Then CLC SOFC and oxy-combustion were modelled to use tail gas. Finally a techno-economic analysis was conducted to calculate each technology's levelised cost of hydrogen (LCOH). It was observed that CO2 purity for CLC meets the criteria for storage (>95%) without further purification. On the other hand from the economic point of view all three technologies show a promising performance with an LCOH of 1.9 €/kg.

The goal of achieving a zero-emission energy system by 2050 requires accurate energy planning to minimise the overall cost of the energy transition. Long-term energy models based on cost-optimal solutions are extremely dependent on the cost forecasts of different technologies. However such forecasts are inherently uncertain. The aim of the present work is to identify a cost-optimal pathway for the Italian energy system decarbonisation and assess how renewable cost scenarios can affect the optimal solution. The analysis has been carried out with the H2RES model a single-objective optimisation algorithm based on Linear Programming. Different cost scenarios for photovoltaics on-shore and off-shore wind power and lithium-ion batteries are simulated. Results indicate that a 100% renewable energy system in Italy is technically feasible. Power-to-X technologies are crucial for balancing purposes enabling a share of non-dispatchable generation higher than 90%. Renewable cost scenarios affect the energy mix however both on-shore and off-shore wind saturate the maximum capacity potential in almost all scenarios. Cost forecasts for lithium-ion batteries have a significant impact on their optimal capacity and the role of hydrogen. Indeed as battery costs rise fuel cells emerge as the main solution for balancing services. This study emphasises the importance of conducting cost sensitivity analyses in long-term energy planning. Such analyses can help to determine how changes in cost forecasts may affect the optimal strategies for decarbonising national energy systems.