Publications

China is the world’s largest carbon emitter and suffers from severe air pollution which results in approximately one million premature deaths/year. Alternative energy vehicles (AEVs) (electric hydrogen fuel cell and natural gas vehicles) can reduce carbon emissions and improve air quality. However climate air quality and health benefits of AEVs powered with deeply decarbonized power generation are poorly quantified. Here we quantitatively estimate the air quality health carbon emission and economic benefits of replacing internal combustion engine vehicles with various AEVs. We find co-benefits increase dramatically as the electricity grid decarbonizes and hydrogen is produced from non-fossil fuels. Relative to 2015 a conversion to AEVs using largely non-fossil power can reduce air pollution and associated premature mortalities and years of life lost by 329000 persons/year and 1611000 life years/year. Thus maximizing climate air quality and health benefits of AEV deployment in China requires rapid decarbonization of the power system.

The objective of this pre-normative research (PNR) document is to present a testing procedure for establishing the energy performance of water (steam) electrolyser systems (WE systems) whether grid-connected or off-grid and individual water electrolysers (WEs)/high-temperature electrolysers (HTEs) for the generation of hydrogen by water/steam electrolysis. The WE systems use electricity mostly from variable renewable energy sources. HTE may additionally utilise (waste) heat from energy conversion and other industrial processes. By applying this procedure the determination of the specific energy consumption per unit of hydrogen output under standard ambient temperature and pressure (SATP) conditions allows for an adequate comparison of different WE systems. Also the energy performance potential of WEs or WE systems employing low-temperature water electrolysis (LTWE) technologies compared to HTE employing high-temperature steam electrolysis (HTSEL) technologies may be established under actual hydrogen output conditions by applying this procedure. The test method is to evaluate the specific energy consumption during steady-state operation at specified conditions including rated input power pressure and temperature of hydrogen recommended by the manufacturer of the WE or WE system. The energy efficiency and the electrical efficiency based on higher and lower heating value of hydrogen can be derived from respectively the specific energy consumption and the specific electric energy consumption as additional energy performance indicators (EPIs). In a plant setting the specific energy consumption of an individual water electrolyser including HTE under hydrogen output conditions may also be determined using this testing procedure. This procedure is intended to be used as a general characterisation method for evaluating the energy performance of WEs including HTEs and systems by the research community and industry alike.

The decarbonisation of heat supply will play a critical role in meeting the emissions reduction target. There is however great uncertainty associated with the achievable levels of heat decarbonisation and the optimal heat technology mix which can have serious implications for the future electricity and gas demand. This work employs an integrated gas electricity and heat supply model to quantify the impacts of heat decarbonisation pathways on the future electricity and gas demand. A case study in the Great Britain is performed considering two heat decarbonisation scenarios in 2050: one is the predominantly electrified heat supply and the other is the predominantly hydrogen-based heat supply. The electricity demand becomes more volatile in the electrified heat scenario as the peak surges to 107.3 GW compared to 51.1 GW in the 2018 reference scenario while the peak in hydrogen-based heat scenario is 78.4 GW. The peak gas demand declines from 247.6 GW for 2018 to 81.7 GW for electrified heat scenario and to 85.1 GW for hydrogen-based heat scenario confirming that the seasonality associated with heat demand is shifting away from the gas network and towards electricity network. Moreover a sensitivity analysis shows that the future electricity demand is highly sensitive to parameters such as relative heat demand coefficient of performance of air source heat pumps and share of electricity in hydrogen production. Finally the application of a load shifting strategy demonstrates that demand-side flexibility has the potential to maintain the electricity system balance and minimise the generation and network infrastructure requirements arising from heat electrification. While the case study presented in this paper is based on the Great Britain the findings regarding the future electricity and gas demand are relevant for the global energy transition.

The Jet Zero strategy sets out how we will achieve net zero aviation by 2050.<br/>It focuses on the rapid development of technologies in a way that maintains the benefits of air travel whilst maximising the opportunities that decarbonisation can bring to the UK.<br/>The Jet Zero strategy includes a 5-year delivery plan setting out the actions that will need to be taken in the coming years to support the delivery of net zero aviation by 2050. We will be monitoring progress and reviewing and updating our strategy every 5 years.<br/>The strategy is informed by over 1500 responses to the Jet Zero consultation and the Jet Zero further technical consultation to which we have issued a summary of responses and government response.<br/>The Jet Zero investment flightpath is part of a series of roadmaps to be published over the course of 2022 for each sector of the Prime Minister’s Ten point plan for a green industrial revolution.<br/>It showcases the UK’s leading role in the development and commercialisation of new low and zero emission aviation technologies. It also highlights investment opportunities across systems efficiencies sustainable aviation fuels and zero emission aircraft.

Hydrogen energy is an excellent carrier for connecting various renewable energy sources and has many advantages. However hydrogen is flammable and explosive and its density is low and easy to escape which brings inconvenience to the storage and transportation of hydrogen. Therefore hydrogen storage technology has become one of the key steps in the application of hydrogen energy. Solid-state hydrogen storage method has a very high volumetric hydrogen density compared to the traditional compressed hydrogen method. The main issue of solid-state hydrogen storage method is the development of advanced hydrogen storage materials. Metal borohydrides have very high hydrogen density and have received much attention over the past two decades. However high hydrogen sorption temperature slow kinetics and poor reversibility still severely restrict its practical applications. This paper mainly discusses the research progress and problems to be solved of metal borohydride hydrogen storage materials for solid-state hydrogen storage.

Although electricity storage plays a decisive role for the German “Energiewende” and it has become evident that the successful diffusion of technologies is not only a question of technical feasibility but also of social acceptance research on electricity storage technologies from a social science point of view is still scarce. This study therefore empirically explores laypersons’ mindsets and knowledge related to storage technologies focusing on hydrogen. While the results indicate overall supportive attitudes and trust in hydrogen storage some misconceptions a lack of information as well as concerns were identified which should be addressed in future communication concepts.

System durability is crucial for the successful commercialization of polymer electrolyte fuel cells (PEFCs) in fuel cell electric vehicles (FCEVs). Besides conventional electrochemical cycling durability during long-term operation the effect of operation in cold climates must also be considered. Ice formation during start up in sub-zero conditions may result in damage to the electrocatalyst layer and the polymer electrolyte membrane (PEM). Here we conduct accelerated cold start cycling tests on prototype fuel cell stacks intended for incorporation into commercial FCEVs. The effect of this on the stack performance is evaluated the resulting mechanical damage is investigated and degradation mechanisms are proposed. Overall only a small voltage drop is observed after the durability tests only minor damage occurs in the electrocatalyst layer and no increase in gas crossover is observed. This indicates that these prototype fuel cell stacks successfully meet the cold start durability targets for automotive applications in FCEVs.

To abate climate change and ameliorate the air quality in urban areas innovative solutions are required to reduce CO2 and pollutant emissions from traffic. Alternative fuels made from biomass or CO2 and hydrogen can contribute to these goals by substituting fossil gasoline or diesel in combustion engines. Using a conjoint analysis approach the current study investigates preferences of laypeople (n = 303) for fuel production facilities in terms of siting location plant size raw material used in the production and raw material transport. The location was most decision-relevant followed by raw material transport whereas plant size and type of raw material played a less prominent role for the preference choice. The best-case scenario from the point of view of acceptance would be the installation of a rather small bio-hybrid fuel production plant in an industrial area (instead of an agricultural or pristine environment). No transport or transport via underground pipeline were preferred over truck/tank car or overground pipeline. The findings can be used as a basis for planning and decision-making for designing production networks for new fuel types.

The goal of achieving water electrolysis on a gigawatt scale faces numerous challenges regarding technological feasibility and market application. Here the flexibility of operation scenarios such as load changes and capacity of electrolysis plays a key role. This raises the question of how flexible electrolysis systems currently are and what possibilities there are to increase flexibility. In order to be able to answer this question in the following a systematic literature research was carried out with the aim to show the current technical possibilities to adapt load and capacity of electrolysis technologies and to determine limits. The result of the systematic literature research is an overview matrix of the electrolysis types AEL PEMEL HTEL and AEMEL already applied in the market. Technical data on the operation of the respective electrolysis stacks as well as details and materials for the respective stack structure (cathode anode electrolyte) were summarized. The flexibility of the individual technologies is addressed by expressing it in values such as load flexibility and startup-times. The overview matrix contains values from various sour1ces in order to make electrolysis comparable at the stack level and to be able to make statements about flexibility. The result of the overview article shows the still open need for research and development to make electrolysis more flexible.

The purpose of this paper is to discuss the potential of hydrogen obtained from renewable sources for energy generation and storage systems. The first part of analysis will address such issues as various methods of green hydrogen production storage and transportation. The review of hydrogen generation methods will be followed by the critical analysis and the selection of production method. This selection is justified by the results of the comparative research on alternative green hydrogen generation technologies with focus on their environmental impacts and costs. The comparative analysis includes the biomass-based methods as well as water splitting and photo-catalysis methods while water electrolysis is taken as a benchmark. Hydrogen storage and transportation issues will be further discussed in purpose to form the list of recommended solutions. In the second part of the paper the technology readiness and technical feasibility for joint hydrogen applications will be analysed. This will include the energy storage and production systems based on renewable hydrogen in combination with hydrogen usage in mobility systems as well as the stationary applications in buildings such as combined heat and power (CHP) plants or fuel cell electric generators. Based on the analysis of the selected case studies the author will discuss the role of hydrogen for the carbon emission reduction with the stress on the real value of carbon footprint of hydrogen depending on the gas source storage transportation and applications.