Publications

Biomass gasification for hydrogen (H2) production provides outstanding advantages in terms of renewable energy resources carbon neutral high efficiency and environmental benefits. However the factors influencing H2 production from biomass gasification are complex which makes determining the optimal operating conditions challenging. Biomass gasification also poses challenges owing to the high associated tar content and low gas yield which need to be overcome. This review summarizes the influence of the gasification parameters on H2 production. Catalytic gasification technology and some of the latest catalysts such as composites and special structure catalysts are also summarized herein based on the requirements of high-purity H2 production. Moreover novel technologies such as staged gasification chemical looping gasification and adsorption-enhanced reforming for producing H2 rich gas are introduced. Finally the challenges and prospects associated with biomass gasification for H2 production are presented.

‘E-fuels’ or ‘synthetic fuels’ are hydrocarbon fuels synthesized from hydrogen (H2) and carbon dioxide (CO2) where H2 can be produced via electrolysis of water or steam reforming of natural gas and CO2 is captured from the combustion of a fossil or biogenic source or directly from the atmosphere. E-fuels are drop-in substitutes for fossil fuels but their climate change mitigation benefits are largely unclear. This study evaluates the climate change impacts of e-fuels for aviation by combining different sources of CO2 and H2 up to 2050 under two contrasting policy scenarios. The analysis includes different climate metrics and the effects of near-term climate forcers which are particularly relevant for the aviation sector. Results are produced for European average conditions and for Poland and Norway two countries with high and low emission intensity from their electricity production mix. E-fuels can either have higher or lower climate change impacts than fossil fuels depending on multiple factors such as in order of importance the electricity mix the origin of CO2 the technology for H2 production and the electrolyzer efficiency. The climate benefits are generally higher for e-fuels produced from CO2 of biogenic origin while e-fuels produced from CO2 from direct air capture or fossil fuel combustion require countries with clean electricity to outperform fossil fuels. Synthetic fuels produced from H2 derived from natural gas have higher impacts than fossil fuels even when coupled with carbon capture and storage if CO2 is sourced from fossil fuels or the atmosphere. Climate change impacts of e-fuels improve in the future and they can all achieve considerable climate change mitigation in 2050 relative to fossil jet fuel provided that strict climate policy measures are implemented to decarbonize the electricity sector. Under reduced policy efforts future climate impacts in 2050 of e-fuels from atmospheric or fossil CO2 are still higher than those of fossil jet fuels with an average European electricity mix. This study shows the conditions to maximize the climate change mitigation benefits of e-fuels which essentially depend on progressive decarbonization of the electricity sector and on reduced use of CO2 sourced from fossil fuels.

Hydrogen (H2 ) is currently a highly attractive fuel for internal combustion engines (ICEs) owing to the prospects of potentially near-zero emissions. However the production emissions and cost of H2 fuel necessitate substantial improvements in ICE thermal efficiency. This work aims to investigate a potential implementation of H2 combustion in a highly efficient double compression-expansion engine (DCEE). DICI nonpremixed H2 combustion mode is used for its superior characteristics as concluded in previous studies. The analysis is performed using a 1D GT-Power software package where different variants of the DICI H2 and diesel combustion cycles obtained experimentally and numerically (3D CFD) are imposed in the combustion cylinder of the DCEE. The results show that the low jet momentum free jet mixing dominated variants of the DICI H2 combustion concept are preferred owing to the lower heat transfer losses and relaxed requirements on the fuel injection system. Insulation of the expander and removal of the intercooling improve the engine efficiency by 1.3 and 0.5 %-points respectively but the latter leads to elevated temperatures in the high-pressure tank which makes the selection of its materials harder but allows the use of cheaper oxidation catalysts. The results also show that the DCEE performance is insensitive to combustion cylinder temperatures making it potentially suitable for other high-octane fuels such as methane methanol ammonia etc. Finally a brake thermal efficiency of 56 % is achieved with H2 combustion around 1 %-point higher than with diesel. Further efficiency improvements are also possible with a fully optimized H2 combustion system.

The search for new fuels to supersede fossil fuels has been intensified these recent decades. Among these fuels hydrogen has attracted much interest due to its advantages mainly cleanliness and availability. It can be produced from various raw materials (e.g. water biomass) using many resources mainly water electrolysis and natural gas reforming. However water electrolysis combined with renewable energy sources is the cleanest way to produce hydrogen while reducing greenhouse gases. Besides hydrogen can be used by fuel cells for producing both electrical and thermal energy. The aim of this work was towards efficient integration of this system into energy efficient buildings. The system is comprised of a photovoltaic system hydrogen electrolyzer and proton exchange membrane fuel cell operating as a cogeneration system to provide the building with both electricity and thermal energy. The system’s modeling simulations and experimentations were first conducted over a short-run period to assess the system’s performance. Reported results show the models’ accuracy in analyzing the system’s performance. We then used the developed models for long-run testing of the hybrid system. Accordingly the system’s electrical efficiency was almost 32%. Its overall efficiency reached 64.5% when taking into account both produced electricity and thermal energy.

Development of hydrogen facilities such as hydrogen refuelling stations (HRS) at scale is a fine balance between economy and safety where an optimal solution would both prevent showstoppers due to cost of increased safety measures and prevent showstoppers due to hydrogen accidents. A detailed Quantitative Risk Analysis (QRA) methodology is presented where the aim is to establish the total risk of the facility and use it to find the right level of safety features such as blast walls and layout. With upscaled hydrogen facilities comes larger area footprints and more potential leak points. These effects will cause increased possible consequence in terms of vapour cloud explosions and increased leak frequencies. Both effects contributing negative to the total risk of the hydrogen facility. At the same time as the number of such facilities is increasing rapidly the frequency of incidents can also increase. A risk-based approach is employed where inherently safe solutions is investigated and cost efficient and acceptable solutions can be established. The present QRA uses well established tools such as SAFETI FLACS and Express which are fitted for hydrogen risks. By using the established Explosion Risk Analysis tool Express the explosion risk inside the station can be found. By using CFD tools actively one can point at physical risk drivers such as equipment layout that can minimize gas cloud build-up on the station. The explosion simulations are further used to find the effects of e.g. blast wall on the pressures affecting on people on the other side of the wall. This is used together with the results from the SAFETI analysis to develop risk contours around the facility. Current standardized safety distances are discussed by considering the effects of scaling and risk drivers on the safety distances. The methodology can be used to develop certain requirement for how hydrogen facilities should be built inherently safe and in cost-efficient ways.

The development of safe dispensing equipment for the fueling of heavy duty (HD) vehicles is critical to the expansion of this newly and quickly expanding market. This paper discusses the development of a HD dispenser and nozzles assembly (nozzle hose breakaway) for these new larger vehicles where flow rates are more than double compared to light duty (LD) vehicles. This equipment must operate at nominal pressures of 700 bar -40o C gas temperature and average flow rate of 5-10 kg/min at a high throughput commercial hydrogen fueling station without leaking hydrogen. The project surveyed HD vehicle manufacturers station developers and component suppliers to determine the basic specifications of the dispensing equipment and nozzle assembly. The team also examined existing codes and standards to determine necessary changes to accommodate HD components. From this information the team developed a set of specifications which will be used to design the dispensing equipment. In order to meet these goals the team performed computational fluid dynamic pressure modelling and temperature analysis in order to determine the necessary parameters to meet existing safety standards modified for HD fueling. The team also considered user operational and maintenance requirements such as freeze lock which has been an issue which prevents the removal of the nozzle from LD vehicles. The team also performed a failure mode and effects analysis (FMEA) to identify the possible failures in the design. The dispenser and nozzle assembly will be tested separately and then installed on an innovative HD fueling station which will use a HD vehicle simulator to test the entire system.

Governments and other stakeholders actively promote and facilitate the development and deployment of hydrogen and fuel cell technologies. Various strategy documents and energy forecasts outline the environmental and societal benefits of the prospective hydrogen economy. At the same time the safety related properties of hydrogen imply that it is not straightforward to achieve and document the same level of safety for hydrogen systems compared to conventional fuels. Severe accidents can have major impact on the development of energy technologies. The stakes will increase significantly as the use of hydrogen shifts from controlled environments in industrial facilities to the public domain and as the transport-related consumption extends from passenger cars and buses to trains ships and airplanes. Widespread deployment of hydrogen as an energy carrier in society will require massive investments. This implies commercial and political commitment involvement and influence on research priorities and decision-making. The legacy from accidents and the messages communicated by influential stakeholders impact not only how the public perceives hydrogen technologies but also governmental policies the development of regulations codes and standards (RCS) and ultimately the measures adopted for preventing and mitigating accidents. This paper explores whether and how selected aspects of safety are considered when distinct groups of stakeholders frame the hydrogen economy. We assess to what extent the communication is consistent with the current state-of-the-art in hydrogen safety and the contemporary strength of knowledge in risk assessments for hydrogen systems. The approach adopted entails semi-quantitative text analysis and close reading to highlight variations between diverse groups of stakeholders. The results indicate a bias in the framing of the safety-related aspects of the hydrogen economy towards procedural organisational and societal measures of risk reduction at the expense of well-known challenges and knowledge gaps associated with the implications of fundamental safety-related properties of hydrogen.

This independent cross-party report highlights the key role that political consensus can play in helping to reduce the costs of nuclear power in the UK as well as other low carbon technologies. This political consensus has never been more important than in this ‘defining decade’ for the power sector. The report highlights that an immediate challenge facing the UK’s new build programme is agreeing with the European Commission a regime for supporting new nuclear power. Changing the proposed support package would not be an impossible task if made necessary but maintaining broad political consensus and considering the implications of delay are also important. The State Aid process is an important opportunity for scrutiny with the report demonstrating that shareholders for Hinkley Point C could see bigger returns (19-21%) than those typically expected for PFI projects (12-15%). However it is too early to conclude on the value for money of the Hinkley Point C agreement. Both the negotiation process and the resulting investment contract are important but there has been little transparency over either so far and the negotiations were not competitive. The inquiry calls for more urgency and better coordination in seizing the opportunity to reuse the UK’s plutonium stockpile.



The UK’s stockpile of separated plutonium presents opportunities to tackle a number of national strategic priorities including implementing long term solutions for nuclear waste developing new technologies that could redefine the sector laying the ground for new nuclear power and pursuing nuclear non-proliferation.  Government has identified three ‘credible solutions’ for reuse and the report recommends that it now sets clearer criteria against which to assess options and identifies budgetary requirements to help expediate the process. The report also argues that Government should do more on new nuclear technologies that could redefine the sector – such as considering smaller reactors nuclear for industrial heat or hydrogen production and closed or thorium fuel cycles. The Government’s initial response to a review of nuclear R&D a year ago by the then Chief Scientific Advisor Sir John Beddington has been welcome and it needs to build on this. In particular the UK should capitalise upon its existing expertise and past experience to focus efforts where there is most strategic value. Nulcear waste. Having failed to date the Government must urgently revisit plans for finding a site to store nuclear waste underground for thousands of years. Implementing this is a crucial part of demonstrating that nuclear waste is a manageable challenge. Despite being rejected by Cumbria County Council the continuing strong support amongst communities in West Cumbria for hosting a site is a promising sign.



On affordability the report finds that it is not yet clear which electricity generation technologies will be cheapest in the 2020s and beyond. Coal and gas could get more expensive if fossil fuel and carbon prices rise whilst low carbon technologies could get cheaper as technology costs fall with more deployment. This is the main reason for adopting an ‘all of the above’ strategy including nuclear power until costs become clearer and there is broad consensus behind this general approach.  



On security of supply the inquiry says that deployment of nuclear power is likely to be influenced more by the economics of system balancing rather than technical system balancing challenges which can be met with greater deployment of existing balancing tools. The cost of maintaining system security is likely to mean that the UK maintains at least some baseload capacity such as nuclear power to limit system costs.



On sustainability the report finds that the environmental impacts of nuclear power are comparable to some generation technologies and favourable to others although the long lived nature of some radioactive nuclear waste and the dual use potential of nuclear technology for civil and military applications create unique sustainability challenges which the UK is a world leader in managing.



It is the final report of the Future Electricity Series an independent and cross party inquiry into the UK power sector sponsored by the Institution of Gas Engineers and Managers

Electrification of the heat network in buildings together with a rise in popularity of Electric Vehicles (EVs) will result in a need to make investments in the electrical energy infrastructure in order to prevent congestion. This paper discusses the influence of hydrogen in future smart microgrids on these investments. Moreover smart control strategies i.e. EV management and demand response programs are used in this paper to lower the peak of electrical energy demand resulting in the reduction of these investments. Performances of microgrid with different levels of hydrogen penetration are discussed. It is shown that an increase in the level of hydrogen in the microgrid will reduce the electric grid investments costs but is not economically more beneficial than using ‘green’ gas due to the higher total economic costs.

Fuel cell electric vehicles (FCEV) are developing quickly from passenger vehicles to trucks or fork-lifts. Policymakers are supporting an ambitious strategy to deploy fuel cell electrical vehicles with infrastructure as hydrogen refueling stations (HRS) as the European Green deal for Europe. The hydrogen fuel quality according to international standard as ISO 14687 is critical to ensure the FCEV performance and that poor hydrogen quality may not cause FCEV loss of performance. However the sampling system is only available for nozzle sampling at HRS. If a FCEV may show a lack of performance there is currently no methodology to sample hydrogen fuel from a FCEV itself. It would support the investigation to determine if hydrogen fuel may have caused any performance loss. This article presents the first FCEV sampling system and its comparison with the hydrogen fuel sampling from the HRS nozzle (as requested by international standard ISO 14687). The results showed good agreement with the hydrogen fuel sample. The results demonstrate that the prototype developed provides representative samples from the FCEV and can be an alternative to determine hydrogen fuel quality. The prototype will require improvements and a larger sampling campaign.