United Kingdom

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.

Decarbonising the global housing stock is imperative for reaching climate change targets. In the United Kingdom hydrogen is currently being tested as a replacement fuel for natural gas which could be used to supply low-carbon energy to parts of the country. Transitioning the residential sector towards a net-zero future will call for an inclusive understanding of consumer preferences for emerging technologies. In response this paper explores consumer attitudes towards domestic cooking and heating technologies and energy appliances of the future which could include a role for hydrogen hobs and boilers in UK homes. To access qualitative evidence on this topic we conducted ten online focus groups (N = 58) with members of the UK public between February and April 2022. The study finds that existing gas users wish to preserve the best features of gas cooking such as speed responsiveness and controllability but also desire the potential safety and aesthetic benefits of electric systems principally induction hobs. Meanwhile future heating systems should ensure thermal comfort ease of use energy efficiency and smart performance while providing space savings and noise reduction alongside demonstrable green benefits. Mixed-methods multigroup analysis suggests divergence between support levels for hydrogen homes which implies a degree of consumer heterogeneity. Foremost we find that domestic hydrogen acceptance is positively associated with interest and engagement with renewable energy and fuel poverty pressures. We conclude that internalising the perspectives of consumers is critical to enabling constructive socio-technical imaginaries for low-carbon domestic energy futures.

Underground hydrogen storage (UHS) in aquifers salt caverns and depleted hydrocarbon reservoirs allows for the storage of larger volumes of H2 compared to surface storage in vessels. In this work we investigate the impact of aquifer-related mechanisms and parameters on the performance of UHS in an associated North Sea aquifer using 3D numerical compositional simulations. Simulation results revealed that the aquifer's permeability heterogeneity has a significant impact on the H2 recovery efficiency where a more homogenous rock would lead to improved H2 productivity. The inclusion of relative permeability hysteresis resulted in a drop in the H2 injectivity and recovery due to H2 discontinuity inside the aquifer which leads to residual H2 during the withdrawal periods. In contrast the effects of hydrogen solubility and hydrogen diffusion were negligible when studied each in isolation from other factors. Hence it is essential to properly account for hysteresis and heterogeneity when evaluating UHS in aquifers.

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.

Industries across the world are making the transition to net-zero carbon emissions as government policies and strategies are proposed to mitigate the impact of climate change on the planet. As a result the use of hydrogen as an energy source is becoming an increasingly popular field of research particularly in the aviation sector where an alternative green renewable fuel to the traditional hydrocarbon fuels such as kerosene is essential. Hydrogen can be stored in multiple ways including compressed gaseous hydrogen cryo-compressed hydrogen and cryogenic liquid hydrogen. The infrastructure and storage of hydrogen will play a pivotal role in the realisation of large-scale conversion from traditional fuels with safety being a key consideration. This paper provides a review on previous work undertaken to study the characterisation of both unignited and ignited hydrogen jets which are fundamental phenomena for the utilisation of hydrogen. This includes work that focuses on the near-field flow structure dispersion in the far-field ignition and flame characteristics with multi-physics. The safety considerations are also included. The theoretical models and computational fluid dynamics (CFD) multiphase and reactive flow approaches are discussed. Then an overview of previous experimental work is provided before focusing the review on the existing computational results with comparison to experiments. Upon completion of this review it is highlighted that the complex near-field physics and flow phenomena are areas lacking in research. The near-field flow properties and characteristics are of significant importance with respect to the ignition and combustion of hydrogen.

This paper aims to assess the impact of EU energy and climate policy as a response to Russia’s war in Ukraine on the EU decarbonization enterprise. It showcases how the Russian invasion was a crunch point that forced the EU to abandon its liberal market dogma and embrace in practice an open strategic autonomy approach. This led to an updated energy and climate policy with significant changes underpinning its main pillars interdependence diversification and the focus of market regulation and build-up. The reversal of enforced interdependence with Russia and the legislative barrage to support and build-up a domestic clean energy market unlocks significant emission reduction potential with measures targeting energy efficiency solar wind and hydrogen development; an urban renewable revolution and electricity and carbon market reforms standing out. Such positive decarbonization effects however are weakened by source and fuel diversification moves that extend to coal and shale gas especially when leading to an infrastructure build-up and locking-in gas use in the mid-term. Despite these caveats the analysis overall vindicates the hypothesis that geopolitics constitutes a facilitator and accelerator of EU energy transition.

As subsidies for renewable energy are progressively reduced worldwide electric vehicle charging stations (EVCSs) powered by renewable energy must adopt market-driven approaches to stay competitive. The unpredictable nature of renewable energy production poses major challenges for strategic planning. To tackle the uncertainties stemming from forecast inaccuracies of renewable energy this study introduces a peer-to-peer (P2P) energy trading strategy based on game theory for solar-hydrogen-battery storage electric vehicle charging stations (SHS-EVCSs). Firstly the incorporation of prediction errors in renewable energy forecasts within four SHS-EVCSs enhances the resilience and efficiency of energy management. Secondly employing game theory’s optimization principles this work presents a day-ahead P2P interactive energy trading model specifically designed for mitigating the variability issues associated with renewable energy sources. Thirdly the model is converted into a mixed integer linear programming (MILP) problem through dual theory allowing for resolution via CPLEX optimization techniques. Case study results demonstrate that the method not only increases SHS-EVCS revenue by up to 24.6% through P2P transactions but also helps manage operational and maintenance expenses contributing to the growth of the renewable energy sector.

International standards related to cryogenic hydrogen transferring technologies for mobile applications (filling of trucks ships stationary tanks) are missing and there is lack of experience. The European project ELVHYS (Enhancing safety of liquid and vaporized hydrogen transfer technologies in public areas for mobile applications) aims to provide indications on inherently safer and efficient cryogenic hydrogen technologies and protocols in mobile applications by proposing innovative safety strategies which are the results of a detailed risk analysis. This is carried out by applying an inter-disciplinary approach to study both the cryogenic hydrogen transferring procedures and the phenomena that may arise from the loss of containment of a piece of equipment containing hydrogen. ELVHYS will provide critical inputs for the development of international standards by creating inherently safer and optimized procedures and guidelines for cryogenic hydrogen transferring technologies thus increasing their safety level and efficiency. The aim of this paper is twofold: present the state of the art of liquid hydrogen transfer technologies by focusing on previous research projects such as PRESLHY and introduce the objectives and methods planned in the new EU project ELVHYS.

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.

The Federal Institute of Metrology METAS developed a Hydrogen Field Test Standard (HFTS) that can be used for field verification and calibration of hydrogen refuelling stations. The testing method is based on the gravimetric principle. The experimental design of the HFTS as well as the description of the method are presented here.