United Kingdom

The Energy Innovation Needs Assessment (EINA) aims to identify the key innovation needs across the UK’s energy system to inform the prioritisation of public sector investment in low-carbon innovation. Using an analytical methodology developed by the Department for Business Energy & Industrial Strategy (BEIS) the EINA takes a systemlevel approach and values innovations in a technology in terms of the system-level benefits a technology innovation provides.1. This whole system modelling in line with BEIS’s EINA methodology was delivered by the Energy Systems Catapult (ESC) using the Energy System Modelling Environment (ESMETM) as the primary modelling tool.



To support the overall prioritisation of innovation activity the EINA process analyses key technologies in more detail. These technologies are grouped together into sub-themes according to the primary role they fulfil in the energy system. For key technologies within a sub-theme innovations and business opportunities are identified. The main findings at the technology level are summarised in sub-theme reports. An overview report will combine the findings from each sub-theme to provide a broad system-level perspective and prioritisation.



This EINA analysis is based on a combination of desk research by a consortium of economic and engineering consultants and stakeholder engagement. The prioritisation of innovation and business opportunities presented is informed by a workshop organised for each sub-theme assembling key stakeholders from the academic community industry and government.



This report was commissioned prior to advice being received from the CCC on meeting a net zero target and reflects priorities to meet the previous 80% target in 2050. The newly legislated net zero target is not expected to change the set of innovation priorities rather it will make them all more valuable overall. Further work is required to assess detailed implications.

The Fuel Cell Industry Review 2020 offers data analysis and commentary on key events in the industry in 2020. Now in its seventh year the Review has been compiled by a team led by E4tech - a specialist energy strategy consultancy with deep expertise in the hydrogen and fuel cell sector (see www.e4tech.com).



Despite the title of this publication we’ve said before that the fuel cell ‘industry’ is not a single industry at all. As those inside it know it is divided by different materials stages of maturity applications and regions – all contributors to the fact it has taken time to get going. But it does seem to be getting traction. Part of that is down to decades of hard work and investment in R&D technology improvement and demonstrations. Thankfully part of it is also down to changes in external conditions. Improving air quality is increasingly non-negotiable. Reducing greenhouse gas emissions likewise. And all while maintaining economic development and opportunity.



The growth spurt of the battery industry allied with some of the drivers above has catalysed thinking in where and how fuel cells can fit. Countries and regions which did not support batteries early on are scrambling to catch up and wish not to risk a repeat of their errors with fuel cells. So support is being targeted at industrial development and competitiveness as well as solving societal problems. Which in turn is helping industry to decide on and take investment steps: Weichai’s 20000 unit per annum PEM factory in China; Daimler and Volvo setting up their fuel cell truck JV; CHEM Energy building a factory for remote systems in S Africa."

On 26 June the World Energy Council held a webinar presenting the results of its latest Innovation Insights Brief on hydrogen engaging three key experts on the topic:



Nigel Brandon Dean of the Faculty of Engineering Imperial College London



Craig Knight Director of Industrial Solutions Horizon Fuel Cell Technology



Dan Sadler H21 Project Manager for Equinor



During the webinar the experts answered a series of policy technical and safety questions from the audience. The webinar started with a poll to get a sense of which sectors attendees saw hydrogen playing a key role in 2040 - 77% chose industrial processes 54% mobility and 31% power generation. The questions ranged from the opportunities and limitations of blending hydrogen with natural gas to safety concerns surrounding hydrogen.



KEY HIGHLIGHTS:

How much hydrogen can be blended with natural gas depends on the rules and regulation of each country. The general consensus is that blending 10% by volume of hydrogen presents no safety concerns or specific difficulties. This would provide an opportunity to develop low hydrogen markets. Nevertheless blending should not be the end destination. It is not sufficient to meet carbon abatement targets.



Low carbon ammonia has a role to play in the new hydrogen economy. It is a proven and understood technology which is easier to move around the world and could be used directly as ammonia or cracked back into hydrogen.



One of the main focus today should be to replace grey hydrogen with green hydrogen in existing supply chains as there would be no efficiency losses in the process.



In China the push for hydrogen is transport-related. This is driven by air quality and energy independence concerns. In the next 10 years the full life cost of fuel cell electric vehicles (FCEVs) is expected to be lower than for internal combustion engines. This is due to the fact that FCEVs require less maintenance and that the residual value in the fuel cells is relatively high. At the end of life 95% of the platinum in fuel cells can be repurposed.



FCEVs should not be regarded as competing with battery electric vehicles they sit next to each other on product maps. FCEVs can benefit from the all of the advances in electric drive train systems and electric motors.



To close the webinar attendees were asked whether hydrogen was going through another hype cycle or if it was here to stay. 10% answered hype and 90% here to stay.

Policy led decisions aiming at decarbonizing the economy may well exacerbate existing regional economic imbalances. These effects are seldomly recognised in spatially aggregated top-down and techno-economic decarbonization strategies. Here we present a spatial economic framework that quantifies the gross value added associated with low carbon hydrogen investments while accounting for region-specific factors such as the industrial specialization of regions their relative size and their economic interdependencies. In our case study which uses low carbon hydrogen produced via autothermal reforming combined with carbon capture and storage to decarbonize the energy intensive industries in Europe and in the UK we demonstrate that interregional economic interdependencies drive the overall economic benefits of the decarbonization. Policies intended to concurrently transition to net zero and address existing regional imbalances as in the case of the UK Industrial Decarbonization Challenge should take these local factors into account.

This Insight provides an overview of the recent EU Commission Hydrogen Strategy Energy System Integration Strategy and Industrial Strategy focusing on regulatory issues impacting hydrogen. It looks at the proposed classification and preferences for different sources of hydrogen financial and regulatory support for development of hydrogen supply demand and infrastructure as well as potential regulation of hydrogen markets. Whilst the Hydrogen Strategy underlines the need for hydrogen to decarbonise the economy the Insight concludes that the EU has shown a clear preference for hydrogen based on renewable electricity at the expense of low carbon hydrogen from natural gas even though it recognises the need for low carbon hydrogen. In addition further detail is required on the support mechanisms and regulatory framework if development of new hydrogen value chain is to succeed. Lastly there is little sign that the Commission recognises the change in regulatory approach from the current natural gas framework which will be needed because of the different challenges facing the development of a hydrogen market.

Paper can be downloaded on their website

This latest report describes the potential for CCUS as an important technology during the UK’s energy transition and focuses on the role that metrology (the science of measurement) could play in supporting its deployment. High priority measurement needs and challenges identified within this report include:

• Measuring and comparing the efficiency of different capture techniques and configurations to provide confidence in investments into technologies;
• Improving equations of state to support the development of accurate models used for controlling operational conditions;
• Improving CO₂ flow measurement to support fiscal and financial metering as well as process control and;
• Improving the understanding and validation of dispersion models for emitted CO₂ including plume migration to support safety assessment.

The report can be downloaded from their website

The European Union (EU) has adopted ambitious decarbonization targets for 2050.

Renewable electricity and electrification are the key drivers but are not sufficient on their own to meet the targets. A number of countries expect decarbonized gas (e.g. renewable hydrogen and biomethane) to be part of a future decarbonized energy system.

Within that context this paper examines proposals recently issued by Spain’s energy regulator (CNMC) to define the methodology for remunerating gas distribution and transmission networks and LNG regasification terminals. Their proposals would reduce significantly the remuneration of these activities. Bearing in mind the objective of decarbonization this paper analyzes key features of the proposals and concludes with recommendations. We suggest:

• Adoption of a common methodology for remunerating new investment in gas and electricity infrastructure assets. The Regulatory Asset Base (RAB) approach is a suitable methodology especially for high-risk investment to integrate hydrogen.
• CNMC reconsideration of its proposals for existing assets. The aim should be to ensure that even if remuneration is reduced to some extent investors will still be compensated adequately and that the companies will continue to support the investments needed to digitalize processes deliver natural gas and eventually deliver renewable gas where it is economic to do so. This is an important signal for current and future investors whose investments will be regulated by the CNMC.
• Clarification of the methodology for remunerating renewable gas facilities. If renewable gas (especially hydrogen) requires access to regulated gas networks the CNMC methodology must provide suitable incentives to invest in network expansion and upgrading as required as well as to maintain natural gas operations. Even if no decision is made in the short-term regarding hydrogen it would be prudent to leave the door open by making the regulation compatible with future decisions involving hydrogen development.
• Consideration of potentially stranded assets. The CNMC and the Government should coordinate over the remuneration of infrastructure assets when national policy decisions may lead to the stranding of these assets.
• Decarbonization of the energy system as a whole. The CNMC and the Government should consider how best to promote the decarbonization of the energy system as a whole rather than its individual parts and what role is to be played by regulated networks and by unregulated initiatives in competitive markets especially for the development of hydrogen systems.

​Link to document on OIES website​​​

The Hy4Heat Safety Assessment has focused on assessing the safe use of hydrogen gas in certain types of domestic properties and buildings. The summary reports (the Precis and the Safety Assessment Conclusions Report) bring together all the findings of the work and should be looked to for context by all readers. The technical reports should be read in conjunction with the summary reports. While the summary reports are made as accessible as possible for general readers the technical reports may be most accessible for readers with a degree of technical subject matter understanding. All of the safety assessment reports have now been reviewed by the HSE.<br/><br/>A comparative risk assessment of natural gas versus hydrogen gas including a quantitative risk assessment; and identification of control measures to reduce risk and manage hydrogen gas safety for a community demonstration.

Iridium-containing NaTaO₃ is produced using a one-step hydrothermal crystallisation from Ta₂O₅ and IrCl₃ in an aqueous solution of 10 M NaOH in 40 vol% H₂O₂ heated at 240 °C. Although a nominal replacement of 50% of Ta by Ir was attempted the amount of Ir included in the perovskite oxide was only up to 15 mol%. The materials are formed as crystalline powders comprising cube-shaped crystallites around 100 nm in edge length as seen by scanning transmission electron microscopy. Energy dispersive X-ray mapping shows an even dispersion of Ir through the crystallites. Profile fitting of powder X-ray diffraction (XRD) shows expanded unit cell volumes (orthorhombic space group Pbnm) compared to the parent NaTaO₃ while XANES spectroscopy at the Ir LIII-edge reveals that the highest Ir-content materials contain Ir⁴⁺. The inclusion of Ir⁴⁺ into the perovskite by replacement of Ta⁵⁺ implies the presence of charge-balancing defects and upon heat treatment the iridium is extruded from the perovskite at around 600 °C in air with the presence of metallic iridium seen by in situ powder XRD. The highest Ir-content material was loaded with Pt and examined for photocatalytic evolution of H₂ from aqueous methanol. Compared to the parent NaTaO₃ the Ir-substituted material shows a more than ten-fold enhancement of hydrogen yield with a significant proportion ascribed to visible light absorption.

Evidence-based policy-making has been a much-debated concept. This paper builds on various insights for a novel perspective: policy-driven narrative-based evidence gathering. In a case study of UK priority setting for bioenergy innovation documents and interviews were analysed to identify links between diagnoses of the problem societal visions policy narratives and evidence gathering. This process is illuminated by the theoretical concept of sociotechnical imaginaries—technoscientific projects which the state should promote for a feasible desirable future. Results suggest that evidence has been selectively generated and gathered within a specific future vision whereby bioenergy largely provides an input-substitute within the incumbent centralised infrastructure. Such evidence is attributed to an external expertise thus helping to legitimise the policy framework. Evidence has helped to substantiate policy commitments to expand bioenergy. The dominant narrative has been reinforced by the government’s multi-stakeholder consultation favouring the incumbent industry and by incentive structures for industry co-investment.

In order to inform the Quantified Risk Assessment (QRA) and procedures for the Winlaton trial the gas characteristics relating to the behaviour of the flammable gas have been reviewed for blended natural gas mixtures containing 20% mol/mol hydrogen (hereby referred to as “blend”) for normal operation and 50% mol/mol for fault conditions. This work builds on the findings of the previous HyDeploy gas characteristics report HyD-Rep04-V02-Characteristics.<br/>Click on the supplements tab to view the other documents from this report

Our new independent report finds that hydrogen can play an important role in UK’s ambitious decarbonisation plan and boost its global industrial competitiveness.

Key insights from this new analysis include:

• New independent report from Aurora Energy Research shows that hydrogen can meet up to half of Great Britain’s (GB) final energy demand by 2050 providing an important pathway to reaching UK’s ambitious Net Zero targets.
• The report concludes that both blue hydrogen (produced from natural gas after reforming to remove carbon content) and green hydrogen (produced by using power to electrolyse water) are expected to play an important role providing up to 480TWh of hydrogen or c.45% of GB’s final energy demand by 2050.
• All Net Zero scenarios require substantial growth in low-carbon generation such as renewables and nuclear. Large-scale hydrogen adoption could help to integrate renewables into the power system by reducing the power sector requirement for flexibility during peak winter months and boosting revenues for clean power generators by c. £3bn per year by 2050.
• The rollout of hydrogen could accelerate green growth and enable the development of globally competitive low-carbon industrial clusters while utilising UK’s competitive advantage on carbon capture.
• In facilitating the identification of a cost-effective hydrogen pathway there are some low-regret options for Government to explore including the stimulation of hydrogen demand in key sectors the deployment of CCS in strategic locations and the standardisation of networks. These initiatives could form an important part of the UK Government’s post-COVID stimulus plan.

Read the full report on Aurora Energy Research Website

Carbon capture and storage (CCS) refers to a set of technologies that may offer the potential for large-scale removal of CO₂ emissions from a range of processes – potentially including the generation of electricity and heat industrial processes and the production of hydrogen and synthetic fuels. CCS has both proponents and opponents. Like other emerging low carbon technologies CCS is not without risks or uncertainties and there are various challenges that would need to be overcome if it were to be widely deployed. Policy makers’ decisions as to whether to pursue CCS should be based on a judgement as to whether the risks and uncertainties associated with attempting to deploy CCS outweigh the risks of not having it available as part of a portfolio of mitigation options in future years.

The full report can be found on the Global CSS Institute website at this link

Low temperature methane steam reforming for hydrogen production using experimental developed Ni/Al2O3 catalysts is studied both experimentally and numerically. The catalytic activity measurements were performed at a temperature range of 500–700 ◦C with steam to carbon ratio (S/C) of 2 and 3 under atmospheric pressure conditions. A mathematical analysis to evaluate the reaction feasibility at all different conditions that have been applied by using chemical equilibrium with applications (CEA) software and in addition a mathematical model focused on the kinetics and the thermodynamics of the reforming reaction is introduced and applied using a commercial finite element analysis software (COMSOL Multiphysics 5.0). The experimental results were employed to validate the extracted simulation data based on the yields of the produced H2 CO2 and CO at different temperatures. A maximum hydrogen yield of 2.7 mol/mol-CH4 is achieved at 700 ◦C and S/C of 2 and 3. The stability of the 10%Ni/Al2O3 catalyst shows that the catalyst is prone to deactivation as supported by Thermogravimetric Analysis TGA results.

Hydrogen presents an attractive option to decarbonise the present energy system. Hydrogen can extend the usage of the existing gas infrastructure with low-cost energy storability and flexibility. Excess electricity generated by renewables can be converted into hydrogen. In this paper a novel multi-energy systems optimisation model was proposed to maximise investment and operating synergy in the electricity heating and transport sectors considering the integration of a hydrogen system to minimise the overall costs. The model considers two hydrogen production processes: (i) gas-to-gas (G2G) with carbon capture and storage (CCS) and (ii) power-to-gas (P2G). The proposed model was applied in a future Great Britain (GB) system. Through a comparison with the system without hydrogen the results showed that the G2G process could reduce £3.9 bn/year and that the P2G process could bring £2.1 bn/year in cost-savings under a 30 Mt carbon target. The results also demonstrate the system implications of the two hydrogen production processes on the investment and operation of other energy sectors. The G2G process can reduce the total power generation capacity from 71 GW to 53 GW and the P2G process can promote the integration of wind power from 83 GW to 130 GW under a 30 Mt carbon target. The results also demonstrate the changes in the heating strategies driven by the different hydrogen production processes.

Titanium dioxide coatings have potential applications including photocatalysts for solar assisted hydrogen production solar water disinfection and self-cleaning windows. Herein we report the use of suspension plasma spraying (SPS) for the deposition of conformal titanium dioxide coatings. The process utilises a nanoparticle slurry of TiO₂ (ca. 6 and 12 nm respectively) in water which is fed into a high temperature plasma jet (ca. 7000–20 000 K). This facilitated the deposition of adherent coatings of nanostructured titanium dioxide with predominantly anatase crystal structure. In this study suspensions of nano-titanium dioxide made via continuous hydrothermal flow synthesis (CHFS) were used directly as a feedstock for the SPS process. Coatings were produced by varying the feedstock crystallite size spray distance and plasma conditions. The coatings produced exhibited ca. 90–100% anatase phase content with the emainder being rutile (demonstrated by XRD). Phase distribution was homogenous throughout the coatings as determined by micro-Raman spectroscopy. The coatings had a granular surface with a high specific surface area and consisted of densely packed agglomerates interspersed with some melted material. All of the coatings were shown to be photoactive by means of a sacrificial hydrogen evolution test under UV radiation and compared favourably with reported values for CVD coatings and compressed discs of P25.

There is a growing conversation around the role that hydrogen can play in the future of the UK and how to best harness its potential to secure jobs show climate leadership promote industrial competitiveness and drive innovation. The Government’s ‘Ten Point Plan for a Green Industrial Revolution’ included hydrogen as one of its ten actions targeting 5GW of ‘low carbon’ hydrogen production by 2030. Britain is thus joining the EU US Japan Germany and a host of other countries seeking to be part of the hydrogen economy of the future.<br/><br/>A focus on clean green hydrogen within targeted sectors and hubs can support multiple Government goals – including demonstrating climate leadership reducing regional inequalities through the ‘levelling up’ agenda and ensuring a green and cost-effective recovery from the coronavirus pandemic which prioritises jobs and skills. A strategic hydrogen vision must be honest and recognise where green hydrogen does not present the optimal pathway for decarbonisation – for instance where alternative solutions are already readily available for roll-out are more efficient and cost-effective. A clear example is hydrogen use for heating where it is estimated to require around 30 times more offshore wind farm capacity than currently available to produce enough green hydrogen to replace all gas boilers as well as adding costs for consumers.<br/><br/>This paper considers the offer of hydrogen for key Government priorities – including an inclusive and resilient economic recovery from the pandemic demonstrating climate leadership and delivering for all of society across the UK. It assesses existing evidence and considers the risks and opportunities and how they might inform a strategic vision for the UK. Ahead of the forthcoming Hydrogen Strategy it sets expectations for Government and outlines key recommendations.

In its new report Making the Hydrogen Economy Possible: Accelerating clean hydrogen in an electrified economy the ETC outlines the role of clean hydrogen in achieving a highly electrified net-zero economy. The report sets out how a combination of private-sector collaboration and policy support can drive the initial ramp up of clean hydrogen production and use to reach 50 million tonnes by 2030.<br/>Clean hydrogen will play a complementary role to decarbonise sectors where direct electrification is likely to be technologically very challenging or prohibitively expensive such as in steel production and long-distance shipping. The report highlights how critical rapid ramp-up of production and use in the 2020s is to unlock cost reductions and to make mid-century growth targets achievable.<br/>This report is part of the ETC’s wider Making Mission Possible Series – a series of reports outlining how to scale up clean energy provision within the next 30 years to meet the needs of a net-zero greenhouse gas emissions (GHG) economy by mid-century. The reports in the series analyse and set out specific actions required in the next decade to put this net-zero by 2050 target within reach.

Globally the accelerating use of renewable energy sources enabled by increased efficiencies and reduced costs and driven by the need to mitigate the effects of climate change has significantly increased research in the areas of renewable energy production storage distribution and end-use. Central to this discussion is the use of hydrogen as a clean efficient energy vector for energy storage. This review by experts of Task 32 “Hydrogen-based Energy Storage” of the International Energy Agency Hydrogen TCP reports on the development over the last 6 years of hydrogen storage materials methods and techniques including electrochemical and thermal storage systems. An overview is given on the background to the various methods the current state of development and the future prospects. The following areas are covered; porous materials liquid hydrogen carriers complex hydrides intermetallic hydrides electro-chemical storage of energy thermal energy storage hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage

Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+ Mg2+ and Ca2+ while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie Skłodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed.

The UK government heat strategy is partially based on decarbonisation pathways from the UK MARKAL energy system model. We review how heat provision is represented in UK MARKAL identifying a number of shortcomings and areas for improvement. We present a completely revised model with improved estimations of future heat demands and a consistent representation of all heat generation technologies. This model represents all heat delivery infrastructure for the first time and uses dynamic growth constraints to improve the modelling of transitions according to innovation theory. Our revised model incorporates a simplified housing stock model which is used produce highly-refined decarbonisation pathways for residential heat provision. We compare this disaggregated model against an aggregated equivalent which is similar to the existing approach in UK MARKAL. Disaggregating does not greatly change the total residential fuel consumption in two scenarios so the benefits of disaggregation will likely be limited if the focus of a study is elsewhere. Yet for studies of residential heat disaggregation enables us to vary consumer behaviour and government policies on different house types as well as highlighting different technology trends across the stock in comparison with previous aggregated versions of the model.

A low pressure superheated hydrogen-steam system has been used to accelerate the oxidation kinetics while keeping the electrochemical conditions similar to those of the primary water in a pressurized water reactor. The initiation has been investigated using a Constant Extension Rate Tensile (CERT) test. Tests were performed on flat tapered specimens made from Type 316L austenitic stainless steel with strain rates of 2×10^-6 and 2×10^-8 ms^-1 at room temperature and at an elevated temperature of 350 °C. R = 1/6 was chosen as a more oxidizing environment and R = 6 was selected as a more reducing environment where the parameter R represents the ratio between the oxygen partial pressure at the Ni/NiO transition and the oxygen partial pressure. Different exposures (1 day and 5 days) prior to loading were investigated post-test evaluation by scanning electron microscopy.

The trial management philosophy of HyDeploy has been developed to enable the overall objectives of the project to be achieved; the safe demonstration of operating a Gas Distribution Network (GDN) on a blend of natural gas and hydrogen. This document provides an overview of the management and governance processes associated with the trial itself. The operational and safety related undertakings before during and after the trial are summarised within this report as well as the intrial experimental programme. The detailed operational procedures are covered in HyD-Rep09.<br/>The programme structure of HyDeploy consists of three phases: Phase 1: Enabling work for preparation of GS(M)R Exemption Phase 2: Construction and installation of process equipment and Phase 3: Safe injection of hydrogen – the trial.<br/>This report focuses on Phase 3 which has two parts; the Proving Trial and; the Trial. As Statutory Duty Holder Keele is accountable for operation of the network it owns over the course of the trial. Operation and maintenance of the network will be undertaken according to the provisions of the Exemption on the basis of agreed revised procedures (HyD-Rep09) by Keele and Cadent. A governance process is in place to manage the blending of hydrogen into the network. This isdescribed in Sections 2 and 3.<br/>Safety related undertakings will be actioned before during and after the trial to mitigate risks identified through the house-to-house testing (HyD-Rep06) procedural review (HyD-Rep09) and quantitative risk assessment (HyD-Rep02). This scope of the undertakings includes actions associated with the end appliances the network itself and the process equipment to be installed.<br/>The detail of these undertakings is given in Section 4.<br/>As part of the trial an experimental programme has been designed to provide further evidence relating to the interactions of a hydrogen blend on network materials and end appliances. The experimental programme is detailed in Section 5.<br/>Click the supplements tab to see the other documents from this report

Hydrogen is widely considered a clean source of energy from the viewpoint of reduction in carbon dioxide emissions as a countermeasure against global warming and air pollution. Various efforts have been made to develop hydrogen as a viable energy carrier including the implementation of fuel cell vehicles (FCVs) and hydrogen refuelling stations (HRSs). A good network of hydrogen refuelling stations is essential for operating FCVs and several hydrogen refuelling stations have been constructed and are in operation worldwide [1]. However despite the potential benefits of hydrogen its flammability creates significant safety concerns. Furthermore even though the energy density of hydrogen is lower than that of gasoline and there is no carbon present which means the amount of radiant heat flux released during combustion is relatively small hydrogen must be handled at high pressure in order to make the cruising range of a fuel cell vehicle (FCV) equal to that of gasoline-powered vehicles. Therefore it is essential to properly evaluate these safety concerns and take reasonable and effective countermeasures. Approximately 50 accidents and incidents involving HRSs have been reported globally [2]. Sakamoto et al. [2] analysed accidents and incidents at HRSs in Japan and the USA to identify the safety issues. Most types of accidents and incidents are small leakages of hydrogen but some have led to serious consequences such as fire and explosion. Recently there was a serious incident in Norway at Kjørbo where a strong explosion was observed [3] – indeed this was within a short time of two other serious incidents in the USA and South Korea showing that the frequency of such incidents may be higher as deployments increase. Use of hydrogen forklifts (and the associated refuelling infrastructure) is another challenge to consider. Hydrogen refuelling stations are often installed in urban areas facing roads and are readily accessible to everyone. Therefore a key measure to approve the hydrogen refuelling stations is safety distances between the hydrogen infrastructure and the surrounding structures such as office buildings or residential dwellings. Whilst a lot of work has been carried out on safety distances (see e.g. [4-6) the accident scenario assumptions and safety distances varied widely in those studies. As a result no consensus has yet emerged on the safety distances to be used and efforts are still needed to bridge the gap between international standards and local regulations (see e.g. [7-8]). The paper analyses this issue and provides guidance on the way forward.

UK homes are primarily heated by fossil fuels and contribute 13% of UK’s carbon footprint (equivalent to all the UK’s 38.4m cars). The report says this is incompatible with UK climate legislation targeting net-zero economy by 2050. New polling finds that consumers are open to cleaner greener ways to heat their homes into the future but that they are “still in the dark about smarter greener heating solutions and lack access to independent advice to help them make better decisions for their homes pockets and the planet”.<br/><br/>The report – Uncomfortable Home Truths: why Britain urgently needs a low carbon heat strategy – says a bold new national roadmap is needed by 2020 which puts consumers and households at the heart of a revolution in green heat innovation. It recommends the creation of an Olympic-style delivery body to catalyse and coordinate regional innovation and local leadership tailored to different parts of the UK and the nation’s diverse housing stock.<br/><br/>This report is the third in the Future Gas Series which has explored the opportunities and challenges associated with using low carbon gas in the energy system and is backed by cross-party parliamentary co-Chairs

We demonstrate a new approach for producing highly dispersed supported metal phosphide powders with small particle size improved stability and increased electrocatalytic activity towards some useful reactions. The approach involves a one-step conversion of metal supported on high surface area carbon to the metal phosphide utilising a very simple and scalable synthetic process. We use this approach to produce PdP₂ and Pd₅P₂ particles dispersed on carbon with a particle size of 4.5–5.5 nm by converting a commercially available Pd/C powder. The metal phosphide catalysts were tested for the oxygen reduction hydrogen oxidation and evolution and formic acid oxidation reactions. Compared to the unconverted Pd/C material we find that alloying the P at different levels shifts oxide formation on the Pd to higher potentials leading to greater stability during cycling studies (20% more ECSA retained 5k cycles) and in thermal treatment under air. Hydrogen absorption within the PdP₂ and Pd₅P₂ particles is enhanced. The phosphides compare favourably to the most active catalysts reported to date for formic acid oxidation especially PdP₂ and there is a significant decrease in poisoning of the surface compared to Pd alone. The mechanistic changes in the reactions studied are rationalised in terms of increased water activation on the surface phosphorus atoms of the catalyst. One of the catalysts PdP₂/C is tested in a fuel cell as anode and cathode catalyst and shows good performance.

Numerical experiments are performed to understand different regimes of hydrogen non-premixed combustion in an enclosure with passive ventilation through one horizontal or vertical vent located at the top of a wall. The Reynolds averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) model with a reduced chemical reaction mechanism is described in detail. The model is based on the renormalization group (RNG) k-ε turbulence model the eddy dissipation concept (EDC) model for simulation of combustion coupled with the 18-step reduced chemical mechanism (8 species) and the in-situ adaptive tabulation (ISAT) algorithm that accelerates the reacting flow calculations by two to three orders of magnitude. The analysis of temperature and species (hydroxyl hydrogen oxygen water) concentrations in time as well as the velocity through the vent shed a light on regimes and dynamics of indoor hydrogen fires. A well-ventilated fire is simulated in the enclosure at a lower release flow rate and complete combustion of hydrogen within the enclosure. Fire becomes under-ventilated at higher release flow rates with two different modes observed. The first mode is the external flame stabilised at the enclosure vent at moderate release rates and the second mode is the self-extinction of combustion inside and outside the enclosure at higher hydrogen release rates. The simulations demonstrated a complex reacting flow dynamics in the enclosure that leads to formation of the external flame or the self-extinction. The air intake into the enclosure at later stages of the process through the whole vent area is a characteristic feature of the self-extinction regime. This air intake is due to faster cooling of hot combustion products by sustained colder hydrogen leak compared to the generation of hot products by the ceasing chemical reactions inside the enclosure and hydrogen supply. In general an increase of hydrogen sustained release flow rate will change fire regime from the well-ventilated combustion within the enclosure through the external flame stabilised at the vent and finally to the self-extinction of combustion throughout the domain.

From an evaluation of the GB housing stock it is clear that a mosaic of low carbon heating technologies will be needed to reach net zero. While heat pumps are an important component of this mix our analysis shows that it is likely to be impractical to heat many GB homes with heat pumps only. A combination of lack of exterior space and/or the thermal properties of the building fabric mean that a heat pump is not capable of meeting the space heating requirement of 8 to 12m homes (or 37% to 54% of the 22.7m homes assessed in this report) or can do so only through the installation of highly disruptive and intrusive measures such as solid wall insulation. Hybrid heat pumps that are designed to optimise efficiency of the system do not have the same requirements of a heat pump and may be a suitable solution for some of these homes. This is likely to mean that decarbonised gas networks are therefore critical to delivery of net zero. 3 to 4m homes1 (or 14% to 18% of homes assessed in our analysis) could be made suitable for heat pump retrofit through energy efficiency measures such as cavity wall insulation. For 7 to 10m homes there are no limiting factors and they require minimal/no upgrade requirements to be made heat pump-ready. Nevertheless given firstly the levels of disruption to the floors and interiors of homes caused by the installation of heat pumps and secondly the cost and disruption associated with the requirement to significantly upgrade the electricity distribution networks to cope with large numbers of heat pumps operating at peak demand times - combined with the availability of a decarbonised gas network which requires a simple like-for-like boiler replacement - is likely to mean that many of these ‘swing’ properties will be better served through a gas based technology such as hydrogen (particularly when consumer choice is factored in) or a hybrid system. A recent trial run in winter 2018-19 by the Energy System Catapult revealed that all participants were reluctant to make expensive investments to improve the energy efficiency of their homes just to enhance the performance of their heat pump. They were more interested in less costly upgrades and tangible benefits such as lower bills or greater comfort. This means that renewable gases including hydrogen as heating fuels are a crucial component of the journey to net zero and the UK’s hydrogen ambitions should be reflective of this. The analysis presented in this paper focuses on the external fabric of the buildings further analysis should be undertaken to consider the internal system changes that would be required for heat pumps and hydrogen boilers for example BEIS Domestic Heat Distribution Systems: Gathering Report from February 2021 which considers the suitability of radiators for the low carbon transition.

The CCUS Advisory Group (CAG) established in March 2019 is an industry-led group considering the critical challenges facing the development of CCUS market frameworks and providing insight into potential solutions. The CAG brings together experts from across the CCUS industry finance and legal sectors.<br/>The CAG has examined a range of business models focusing on industrial CCUS power production CO? transport and storage and hydrogen production. It has considered how the proposed business models interact in order to minimise issues such as cross-chain risk and has considered issues such as delivery capability. The conclusions of the CAG can be found in this report.

Hydrogen presents an opportunity for Africa to not only decarbonise its own energy use and enable clean energy access for all but also to export renewable energy. This paper developed a framework for assessing renewable resources for hydrogen production and provides a new critical analysis as to how and what role hydrogen can play in the complex African energy landscape. The regional solar wind CSP and bio hydrogen potential ranges from 366 to 1311 Gt/year 162 to 1782 Gt/year 463 to 2738 Gt/year and 0.03 to 0.06 Gt/year respectively. The water availability and sensitivity results showed that the water shortages in some countries can be abated by importing water from regions with high renewable water resources. A techno-economic comparative analysis indicated that a high voltage direct current (HVDC) system presents the most cost-effective transportation system with overall costs per kg hydrogen of 0.038 $/kg followed by water pipeline with 0.084 $/kg seawater desalination 0.1 $/kg liquified hydrogen tank truck 0.12 $/kg compressed hydrogen pipeline 0.16 $/kg liquefied ammonia pipeline 0.38 $/kg liquefied ammonia tank truck 0.60 $/kg and compressed hydrogen tank truck with 0.77 $/kg. The results quantified the significance of economies of scale due to cost effectiveness of systems such as compressed hydrogen pipeline and liquefied hydrogen tank truck systems when hydrogen production is scaled up. Decentralization is favorable under some constraints e.g. compressed hydrogen and liquefied ammonia tank truck systems will be more cost effective below 800 km and 1400 km due to lower investment and operation costs.

Renewable energy is a key solution in maintaining global warming below 2 °C. However its intermittency necessitates the need for energy conversion technologies to meet demand when there are insufficient renewable energy resources. This study aims to tackle these challenges by thermo-electrochemical modelling and simulation of a reversible solid oxide fuel cell (RSOFC) and integration with the Haber Bosch process. The novelty of the proposed system is usage of nitrogen-rich fuel electrode exhaust gas for ammonia synthesis during fuel cell mode which is usually combusted to prevent release of highly flammable hydrogen into the environment. RSOFC round-trip efficiencies of 41–53% have been attained when producing excess ammonia (144 kg NH3/hr) for the market and in-house consumption respectively. The designed system has the lowest reported ammonia electricity consumption of 6.4–8.21 kWh/kg NH₃ power-to-hydrogen power-to-ammonia and power-generation efficiencies of 80% 55–71% and 64–66%.

Electrolysis is seen as a promising route for the production of hydrogen from water as part of a move to a wider “hydrogen economy”. The electro-oxidation of renewable feedstocks offers an alternative anode couple to the (high-overpotential) electrochemical oxygen evolution reaction for developing low-voltage electrolysers. Meanwhile the exploration of new membrane materials is also important in order to try and reduce the capital costs of electrolysers. In this work we synthesise and characterise a previously unreported anion-exchange membrane consisting of a fluorinated polymer backbone grafted with imidazole and trimethylammonium units as the ion-conducting moieties. We then investigate the use of this membrane in a lignin-oxidising electrolyser. The new membrane performs comparably to a commercially-available anion-exchange membrane (Fumapem) for this purpose over short timescales (delivering current densities of 4.4 mA cm⁻² for lignin oxidation at a cell potential of 1.2 V at 70 °C during linear sweep voltammetry) but membrane durability was found to be a significant issue over extended testing durations. This work therefore suggests that membranes of the sort described herein might be usefully employed for lignin electrolysis applications if their robustness can be improved.

Hydrogen jet fires from a thermally activated pressure relief device (TPRD) on onboard storage are considered for a vehicle in a naturally ventilated covered car park. Computational Fluid Dynamics was used to predict behaviour of ignited releases from a 70 MPa tank into a naturally ventilated covered car park. Releases through TPRD diameters 3.34 2 and 0.5 mm were studied to understand effect on hazard distances from the vehicle. A vertical release and downward releases at 0° 30° and 45° for TPRD diameters 2 and 0.5 mm were considered accounting for tank blowdown. direction of a downward release was found to significantly contribute to decrease of temperature in a hot cloud under the ceiling. Whilst the ceiling is reached by a jet exceeding 300 °C for a release through a TPRD of 2 mm for inclinations of either 0° 30° or 45° an ignited release through a TPRD of 0.5 mm and angle of 45° did not produce a cloud with a temperature above 300 °C at the ceiling during blowdown. The research findings specifically regarding the extent of the cloud of hot gasses have implications for the design of mechanical ventilation systems.

Natural gas based hydrogen production with carbon capture and storage is referred to as blue hydrogen. If substantial amounts of CO2 from natural gas reforming are captured and permanently stored such hydrogen could be a low-carbon energy carrier. However recent research raises questions about the effective climate impacts of blue hydrogen from a life cycle perspective. Our analysis sheds light on the relevant issues and provides a balanced perspective on the impacts on climate change associated with blue hydrogen. We show that such impacts may indeed vary over large ranges and depend on only a few key parameters: the methane emission rate of the natural gas supply chain the CO2 removal rate at the hydrogen production plant and the global warming metric applied. State-of-the-art reforming with high CO2 capture rates combined with natural gas supply featuring low methane emissions does indeed allow for substantial reduction of greenhouse gas emissions compared to both conventional natural gas reforming and direct combustion of natural gas. Under such conditions blue hydrogen is compatible with low-carbon economies and exhibits climate change impacts at the upper end of the range of those caused by hydrogen production from renewable-based electricity. However neither current blue nor green hydrogen production pathways render fully “net-zero” hydrogen without additional CO2 removal.

In response to the global climate emergency governments across the world are aiming to lower greenhouse gas emissions to slow the damaging effects of climate change.<br/>The Scottish Government has set a target of net zero emissions by 2045. Already a global leader in renewable energy and low-carbon technology deployment Scotland’s energy landscape is set to undergo more change as it moves toward becoming carbon-neutral. Key to that change will be the transition from natural gas to zero-carbon gases like hydrogen and biomethane.<br/>Scotland’s north-east and central belt are home to some of its largest industrial carbon emitters. The sector’s reliance on natural gas means that it emits 11.9Mt of CO2 emissions per year says NECCUS: the equivalent of 2.6 million cars or roughly all the cars in Scotland. Most homes and businesses across Scotland also use natural gas for heating.<br/>Our North-East Network and Industrial Cluster project is laying the foundations for the rapid decarbonisation of this high-emitting sector. We’ve published a report outlining the practical steps needed to rapidly decarbonise a significant part of Scotland’s homes and industry. It demonstrates how hydrogen can play a leading role in delivering the Scottish Government’s target of one million homes with low carbon heat by 2030.<br/>The research published with global consulting and engineering advisor Wood sets out a transformational and accelerated pathway to 100% hydrogen for Scotland’s gas networks which you can see on the map below. It also details the feasibility of a CO2 collection network to securely capture transport and store carbon dioxide emissions deep underground.

In this study a green hydrogen system was studied to provide electricity for an office building in the Sharjah emirate in the United Arab Emirates. Using a solar PV a fuel cell a diesel generator and battery energy storage; a hybrid green hydrogen energy system was compared to a standard hybrid system (Solar PV a diesel generator and battery energy storage). The results show that both systems adequately provided the power needed for the load of the office building. The cost of the energy for both the basic and green hydrogen energy systems was 0.305 USD/kWh and 0.313 USD/kWh respectively. The cost of the energy for both systems is very similar even though the capital cost of the green hydrogen energy system was the highest value; however the replacement and operational costs of the basic system were higher in comparison to the green hydrogen energy system. Moreover the impact of the basic system in terms of the carbon footprint was more significant when compared with the green hydrogen system. The reduction in carbon dioxide was a 4.6 ratio when compared with the basic system.

To achieve the UK’s net zero target vehicles including heavy-duty vehicles (HDVs) will need to be entirely decarbonised. The UK government has announced that it plans to phase out the sale of all new cars and vans with engines between 2030 and 2035. It has also announced its intention to consult on a similar phase-out for diesel-powered heavy-goods vehicles (HGVs). This study analyses policies and technologies which can contribute to the decarbonisation of the UK's inland freight sector.



It comprises an emissions modelling exercise and a cost analysis for total cost of ownership (TCO) of long-haul trucks. The study shows that for urban and regional deliveries battery electric trucks offer the best option to decarbonise. It also shows that battery electric trucks and those using an overhead catenary infrastructure are likely to be the most cost-effective pathway to decarbonise long-haul trucks by 2050 but that renewable hydrogen could also be an option.



​Link to Document Download on Transport & Environment website​​​

Future energy systems could rely on hydrogen (H2) to achieve decarbonisation and net-zero goals. In a similar energy landscape to natural gas H2 emissions occur along the supply chain. It has been studied how current gas infrastructure can support H2 but there is little known about how H2 emissions affect global warming as an indirect greenhouse gas. In this work we have estimated for the first time the potential emission profiles (g CO2eq/MJ H2HHV) of H2 supply chains and found that the emission rates of H2 from H2 supply chains and methane from natural gas supply are comparable but the impact on global warming is much lower based on current estimates. This study also demonstrates the critical importance of establishing mobile H2 emission monitoring and reducing the uncertainty of short-lived H2 climate forcing so as to clearly address H2 emissions for net-zero strategies.

A global transition to hydrogen fuel offers major opportunities to decarbonise a range of different energyintensive sectors from large-scale electricity generation through to heating in homes. Hydrogen can be deployed as an energy source in two distinct ways in electrochemical fuel cells and via combustion. Combustion seems likely to be a major pathway given that it requires only incremental technological change. The use of hydrogen is not however without side-effects and the widely claimed benefit that only water is released as a by-product is only accurate when it is used in fuel cells. The burning of hydrogen can lead to the thermal formation of nitrogen oxides (NOx – the sum of NO + NO2) via a mechanism that also applies to the combustion of fossil fuels. NO2 is a key air pollutant that is harmful in its own right and is a precursor to other pollutants of concern such as fine particulate matter and ozone. Minimising NOx as a by-product from hydrogen boilers and engines is possible through control of combustion conditions but this can lead to reduced power output and performance. After-treatment and removal of NOx is possible but this increases cost and complexity in appliances. Combustion applications therefore require optimisation and potentially lower hydrogen-specific emissions standards if the greatest air quality benefits are to derive from a growth in hydrogen use

One of the most challenging sectors to meet “Net Zero emissions” target by 2050 in the UK is the domestic heating sector. This paper provides a comprehensive literature review of the main challenges of heating systems transition to low carbon technologies in which three distinct categories of challenges are discussed. The first challenge is of decarbonizing heat at the supply side considering specifically the difficulties in integrating hydrogen as a low-carbon heating substitute to the dominant natural gas. The next challenge is of decarbonizing heat at the demand side and research into the difficulties of retrofitting the existing UK housing stock of digitalizing heating energy systems as well as ensuring both retrofits and digitalization do not disproportionately affect vulnerable groups in society. The need for demonstrating innovative solutions to these challenges leads to the final focus which is the challenge of modeling and demonstrating future energy systems heating scenarios. This work concludes with recommendations for the energy research community and policy makers to tackle urgent challenges facing the decarbonization of the UK heating sector.

The clean hydrogen in the prioritized value chain platform could provide energy incentives and reduce environmental impacts. In the current study strengths weaknesses opportunities and threats (SWOT) analysis has been successfully applied to the clean hydrogen value chain in different sectors to determine Japan’s clean hydrogen value chain’s strengths weaknesses opportunities and threats as a case study. Japan was chosen as a case study since we believe that it is the only pioneer country in that chain with a national strategy investments and current projects which make it unique in this way. The analyses include evaluations of clean energy development power supply chains regional energy planning and renewable energy development including the internal and external elements that may influence the growth of the hydrogen economy in Japan. The ability of Japan to produce and use large quantities of clean hydrogen at a price that is competitive with fossil fuels is critical to the country’s future success. The implementation of an efficient carbon tax and carbon pricing is also necessary for cost parity. There will be an increasing demand for global policy coordination and inter-industry cooperation. The results obtained from this research will be a suitable model for other countries to be aware of the strengths weaknesses opportunities and threats in this field in order to make proper decisions according to their infrastructures potentials economies and socio-political states in that field.

Previously suggested options to achieve carbon neutrality involve the use of fossil fuels with carbon capture or exploiting biomass as sources of energy. Industrial high-temperature heating could possibly exploit electrical heating or combustion using hydrogen. However it is difficult to replace all the current coal or natural gas furnaces with these options for chemical industry. In this work a method that integrates solid oxide electrolysis cells (SOEC) and H2–O2 combustion is proposed and the related parameters are modelled to analyze their impacts. There is no waste heat and waste emissions in the proposed option and all substances are recycled. Unlike previous research the heat required for SOEC operation is generated from H2 combustion. The best working condition is under thermoneutral voltage and the highest electricity-to-thermal efficiency that can be achieved is 86.88% under a current density of 12000 A/m2 and operating temperature of 750 ◦C. Ohmic overpotential has the greatest effect on electricity consumption and the anode activation overpotential is the second most important option. Increasing combustion product temperature cannot significantly improve thermal efficiency but can raise the available maximum thermal energy.

Since the UK’s Net Zero greenhouse gas emissions target was set in 2019 organisations across the energy systems community have released pathways on how we might get there – which end-use technologies are deployed across each sector of demand how our fossil fuel-based energy supply would be transferred to low carbon vectors and to what extent society must change the way it demands energy services. This paper presents a comparative analysis between seven published Net Zero pathways for the UK energy system collected from Energy Systems Catapult National Grid ESO Centre for Alternative Technology and the Climate Change Committee. The key findings reported are that (i) pathways that rely on less stringent behavioural changes require more ambitious technology development (and vice versa); (ii) electricity generation will increase by 51-160% to facilitate large-scale fuel-switching in heating and transport the vast majority of which is likely to be generated from variable renewable sources; (iii) hydrogen is an important energy vector in meeting Net Zero for all pathways providing 100-591 TWh annually by 2050 though the growth in demand is heavily dependent on the extent to which it is used in supplying heating and transport demand. This paper also presents a re-visited analysis of the potential renewable electricity generation resource in the UK. It was found that the resource for renewable electricity generation outstrips the UK’s projected 2050 electricity demand by a factor 12-20 depending on the pathway. As made clear in all seven pathways large-scale deployment of flexibility and storage is required to match this abundant resource to our energy demand.

Europe’s low-carbon energy policy favors a greater use of fuel cells and technologies based on hydrogen used as a fuel. Hydrogen delivered at the hydrogen refueling station must be compliant with requirements stated in different standards. Currently the quality control process is performed by offline analysis of the hydrogen fuel. It is however beneficial to continuously monitor at least some of the contaminants onsite using chemical sensors. For hydrogen quality control with regard to contaminants high sensitivity integration parameters and low cost are the most important requirements. In this study we have reviewed the existing sensor technologies to detect contaminants in hydrogen then discussed the implementation of sensors at a hydrogen refueling stations described the state-of-art in protocols to perform assessment of these sensor technologies and finally identified the gaps and needs in these areas. It was clear that sensors are not yet commercially available for all gaseous contaminants mentioned in ISO14687:2019. The development of standardized testing protocols is required to go hand in hand with the development of chemical sensors for this application following a similar approach to the one undertaken for air sensors.

Liquid hydrogen (LH2) has the potential to form part of the UK energy strategy in the future and therefore could see widespread use due to the relatively high energy density when compared to other renewable energy sources. To study the feasibility of this the European Fuel Cells and Hydrogen Joint Undertaking (FCH JU) funded project PRESLHY undertook pre-normative research for the safe use of cryogenic LH2 in non-industrial settings. Several key scenarios were identified as knowledge gaps and both theoretical and experimental studies were conducted to provide insight into these scenarios. This included experiments studying the effect of congestion on an ignited hydrogen plume that develops from a release of LH2; this paper describes the objectives experimental setup and a summary of the results from these activities. Characterisation of the LH2 release hydrogen concentration and temperatures measurements within the resulting gas cloud was undertaken along with pressure measurements both within the cloud and further afield. Various release conditions and congestion levels were studied. Results showed that at high levels of congestion increased overpressures occurred with the higher flow rates studied including one high order event. Data generated from these experiments is being taken forward to generate and validate theoretical models ultimately to contribute to the development of regulations codes and standards (RCS) for LH2."

By considering the weight penalty of batteries on payload and total vehicle weight this paper shows that almost all forms of land-based transport may be served by battery electric vehicles (BEV) with acceptable cost and driving range. Only long-distance road freight is unsuitable for battery electrification. The paper models the future Indian electricity grid supplied entirely by low-carbon forms of generation to quantify the additional solar PV power required to supply energy for transport. Hydrogen produced by water electrolysis for use as a fuel for road freight provides an inter-seasonal energy store that accommodates variations in renewable energy supply. The advantages and disadvantages are considered of midday electric vehicle charging vs. overnight charging considering the temporal variations in supply of renewable energy and demand for transport services. There appears to be little to choose between these two options in terms of total system costs. The result is an energy scenario for decarbonized surface transport in India based on renewable energy that is possible realistically achievable and affordable in a time frame of year 2050.

The turbine-combined free-piston engine generator (TCFPEG) is a hybrid machine generating both mechanical work from the gas turbine and electricity from the linear electric generator for battery charging. In the present study the system performance of the designed TCFPEG system is predicted using a validated numerical model. A parametric analysis is undertaken based on the influence of the engine load valve timing the number of linear generators adopted and different fuels on the system performance. It is found that when linear electric generators are connected with the free-piston gas turbine the bottom dead centre the peak piston velocity and engine operation frequency are all reduced. Very minimal difference on the in-cylinder pressure and the compressor pressure is observed while the peak pressure in the bounce chamber is reduced. When coupled with a linear electric generator the system efficiency can be improved to nearly 50% by optimising engine load and the number of the linear generators adopted in the TCFPEG system. The system is able to be operated with different fuels as the piston is not limited by a mechanical system; the output power and system efficiency are highest when hydrogen is used as the fuel.

IGEM/SR/23 (“Venting of natural gas”) provides recommendations for the conceptual design operation and safety aspects of permanent temporary and emergency venting of natural gas. The document was originally developed many years ago and the current edition dates to 1995. The document is due to be reviewed and updated for application to natural gas but the aim of this study is not to review the applicability of the document for natural gas but to assess the possible impact of 100% hydrogen on specific aspects of the existing guidance.<br/>A key element of the guidance concerns the safe dispersion distances for natural gas as vents are intended to provide a means of safely dispersing gas in the atmosphere without ignition. Guidance on safe dispersion distances for venting are provided in Section 6.6 accompanied by graphs showing the relationship between the mass flow rate through the vent and the safe (horizontal) dispersion distance. Details of the model used to predict the dispersion distances are given in Appendix 1. However for dispersion the guidance in IGEM/SR/23 has been superseded by similar guidance on hazard distances for unignited releases in IGEM/SR/25 (“Hazardous area classification of natural gas installations”) [2]. A comprehensive review of the applicability of IGEM/SR/25 to hydrogen is already underway for the LTS Futures project and is not duplicated here.<br/>However IGEM/SR/23 contains guidance on other important aspects relevant to the safe design and operation of vents which are not addressed elsewhere in the IGEM suite of standards; in particular guidance on hazard ranges for thermal radiation (in the event of an unplanned ignition of the venting gas) and noise.<br/>The main aim of this report is to assess the potential impact of replacing natural gas with 100% hydrogen on the guidance in IGEM/SR/23 concerned with thermal hazards with a secondary objective of assessing the available information to comment on the possible influence of hydrogen on noise.

The H21 National Innovation Competition project is examining the feasibility of repurposing the existing GB natural gas distribution network for transporting 100% hydrogen. It aims to undertake an experimental testing programme that will provide the necessary data to quantify the comparative risk between a 100% hydrogen network and the natural gas network. The first phase of the project focuses on leakage testing of a strategic set of assets that have been removed from service which provide a representative sample of assets across the network. This paper presents the work undertaken for Phase 1A (background testing) where HSE and industry partners have tested a range of natural gas pipework assets of varying size material age and pressure-rating in a new bespoke open-air testing facility at the HSE Science and Research Centre Buxton. The assets have been pressurised with hydrogen and then methane and the leakage rate from the assets measured in both cases. The main finding of this work is that the assets tested which leak hydrogen also leak methane. None of the assets were found to leak hydrogen but not methane. In addition repair techniques that were effective at stopping methane leaks were also effective at stopping hydrogen leaks. The data from the experiments have been interpreted to obtain a range of leakage ratios between the two gases for releases under different conditions. This has been compared to the predicted ratio of hydrogen to methane volumetric leak rates for laminar (1.2:1) and turbulent (2.9:1) releases and good agreement was observed.

Current standard practice at wastewater treatment plants (WWTPs) involves the recycling of digestate liquor produced from the anaerobic digestion of sludge back into the treatment process. However a significant amount of energy is required to enable biological breakdown of ammonia present in the liquor. This biological processing also results in the emission of damaging quantities of greenhouse gases making diversion of liquor and recovery of ammonia a noteworthy option for improving the sustainability of wastewater treatment. This study presents a novel process which combines ammonia recovery from diverted digestate liquor for use (alongside biomethane) in a solid oxide fuel cell (SOFC) system for implementation at WWTPs. Aspen Plus V.8.8 and numerical steady state models have been developed using data from a WWTP in West Yorkshire (UK) as a reference facility (750000p.e.). Aspen Plus simulations demonstrate an ability to recover 82% of ammoniacal nitrogen present in digestate liquor produced at the WWTP. The recovery process uses a series of stripping absorption and flash separation units where water is recovered alongside ammonia. This facilitates effective internal steam methane as a case of study has the potential to make significant impacts energetically and environmentally; findings suggest the treatment facility could transform from a net consumer of electricity to a net producer. The SOFC has been demonstrated to run at an electrical efficiency of 48% with NH3 contributing 4.6% of its power output. It has also been demonstrated that 3.5 kg CO2e per person served by the WWTP could be mitigated a year due to a combination of emissions savings by diversion of ammonia from biological processing and lifecycle emissions associated with the lack of reliance on grid electricity.