Heating indoor spaces by burning natural gas accounts for ~30% of the UK's total CO2 emissions. Around 23 million properties are connected to the gas network. Each 1kg of gas burned delivers ~12kWh of heat and releases ~4kg of CO2. That cannot continue in a future net-zero UK and capturing CO2 at individual buildings is completely implausible using any known technology. Many consider that hydrogen should replace natural gas in the gas network. Technically, this is feasible. Hydrogen can be produced from electrolysis or from natural gas. In case of the latter, 'carbon-capture' methods can collect most of the resulting CO2 and pump that underground. However, distributing hydrogen through the gas network might not necessarily be the most sensible course of action in all cases. This project will answer the question about how best to use different parts of existing gas network in a future net-zero UK. Even with carbon-capture, producing hydrogen from natural gas does cause some CO2 emissions. Typically >5% escapes. Using renewable electricity to make 'green' hydrogen via electrolysis and then burning that in boilers delivers less than 7kWh of heat into homes for every 10kWh of electricity used. By contrast, using electrically driven heat pumps can deliver 40kWh of heat for every 10kWh of electricity consumed. Although there are other advantages to producing hydrogen for heating, it remains questionable whether this is optimal in many parts of the UK. It is very likely that a large fraction of the existing infrastructure will be used for distributing hydrogen across the country. However, some specific parts of the network could be better exploited in a different way. This project will explore the different possible uses for those parts of the gas network. All of these potential uses are motivated mainly by solving problems that would arise if heat pumping were deployed very extensively in the UK as the primary heating mechanism. One possible future use for parts of the gas network is to feed non-potable water into properties. This water could serve as the source of low-temperature heat to support heat pumps. A new variety of heat pump turns incoming water into an ice slurry and discards the slurry to melt again later. This 'Latent Heat Pump' (LHP) can extract a lot of heat out of cold water (12L of water provides ~1kWh of heat). That heat emerges from the water at about 0C and as a consequence, the LHP can have a coefficient-of-performance (COP) >4 even when the outside air is very cold. For most air-source heat pumps, the COP falls sharply in very cold weather and, for obvious reasons, the COP matters most in very cold weather. A second possible future use for the gas network is to serve as a return (collection) network rather than as a delivery (distribution) network. Here, the fluid returning through the gas network would be an aqueous solution of a chemical that was hydrated (mixed with water) at the property to release heat. This measure would be taken only in very cold weather. Calcium Chloride and Magnesium Sulphate are two very cheap salts that release heat when dissolved in water. There are other inexpensive substances that release large quantities of heat upon reacting with water. Finally, if water was being conveyed in the low-pressure tiers of the gas network, the high-pressure tiers of the gas network would be free for another use. A very attractive possibility here would be to use those parts as the pressure vessel for a compressed air energy storage system. That system would simultaneously be able to assist the electricity transmission system by doing a parallel transmission from North to South at times of high North-South power traffic. How acceptable each of these propositions is to key social stakeholders (including policy makers, prospective business, and public end-users) will be integral to their real-world viability, and so will be examined here also.

The production, storage, distribution and conversion of hydrogen is a rapidly emerging candidate to help decarbonise the economy. Here we focus on its role to support the integration of offshore renewable energy (ORE), a topic of increasing importance to the UK given the falling costs of offshore wind generation (with prices expected to drop to 25% of 2017 by 2023) and Government ambition. Indeed, the latest BEIS scenarios include more than 120 GW of offshore wind, and even up to 233GW in some scenarios. This brings with it significant challenges to the electricity infrastructure in terms of our ability to on-shore and integrate these variable energy flows, across a wide range of timeframes. Current ORE plants composed of fixed offshore wind structures are sited relatively close to land in shallow water and use systems of offshore cables and substations to transform the electricity produced, transmit it to the shore and connect to the grid. However, in order to exploit the full renewable energy potential and requirements for the 2050 net zero target, offshore wind farms will need to be sited further offshore and in deeper waters. This brings possibilities into consideration in which transporting the energy to shore via an alternative vector such as hydrogen could become the most attractive route. Hence we consider both on-shore and off-shore hydrogen generation. Not only can hydrogen be an effective means to integrate offshore wind, but it is also increasingly emerging as an attractive low carbon energy carrier to support the de-carbonisation of hard to address sectors such as industrial heat, chemicals, trucks, heavy duty vehicles, shipping, and trains. This is increasingly recognised globally, with significant national commitments to hydrogen in France, China, Canada, Japan, South Korea, Germany, Portugal, Australia and Spain in the last three years alone, along with the recent launch of a European hydrogen strategy, and the inclusion of hydrogen at scale in the November 2020 UK Government Green plan. Most of the focus of these national strategies is on the production of 'green' hydrogen using electrolysis, driven by renewable electricity. However, there remains interest in some countries, the UK being one example, in 'blue' hydrogen, which is hydrogen made from fossil fuels coupled with carbon capture and storage and hence a low carbon rather than zero carbon hydrogen. Today, 96% of hydrogen globally is produced from unabated fossil fuels, with 6% of global natural gas, and 2% of coal, consumption going to hydrogen production, primarily for petrochemicals, contributing around 830 million tonnes of carbon dioxide emissions per year. Currently green hydrogen is the most expensive form of hydrogen, with around 60-80% of the cost coming from the cost of the electrical power input. A critical factor that influences this is the efficiency of the electrolyser itself, and in turn the generator used to convert the green hydrogen back into power when needed. In this work we focus on the concept of a reversible electrolyser, which is a single machine that can both produce power in fuel cell mode, and produce hydrogen in electrolyser mode. Electrolysers and fuel cells fall into one of two categories: low-temperature (70-120C) and high temperature (600-850C). While low temperature electrolyser and fuel cell systems are already commercially available, their relatively low combined round-trip efficiency (around 40%) means that the reversible solid oxide cell (rSOC), which can operate at high temperatures (600-900C) is of growing interest. It can achieve an electrolyser efficiency of up to 95%, power generation efficiency of up to 65%, and hence a round-trip efficiency of around 60% at ambient pressure using products now approaching commercial availability. This project considers the development and application of this new technology to the case of ORE integration using hydrogen.

Hydrogen and alternative liquid fuels (HALF) have an essential role in the net-zero transition by providing connectivity and flexibility across the energy system. Despite advancements in the field of hydrogen research both in the physical sciences and engineering, significant barriers remain to the scalable adoption of hydrogen and alternative liquid fuel technologies, and energy services, into the UK's local and national whole system infrastructure. These are technical barriers, organisational barriers, regulatory and societal barriers, and financial barriers. There are, therefore, significant gaps between current levels of hydrogen production, transportation, storage, conversion, and usage, and the estimated requirement for achieving net-zero by 2050. To address this, our proposed research programme has four interlinked work packages. WP1 will develop forward-thinking HALF technology roadmaps. We will assess supply chain availability and security. Selected representative HALF use cases will be used to identify and quantify any opportunities, risks and dependencies within a whole systems analysis. We will also develop an overarching roadmap for HALF system integration in order to inform technology advancement, industry and business development, as well as policy making and social interventions. WP2 will improve HALF characterisation and explore urgent new perspectives on the energy transition, including those related to ensuring resilience and security while also achieving net-zero. We will contrast the energy transition delivered by real incentives/behaviour versus those projected by widely-used optimisation models. The WP provides the whole systems modelling engine of the HI-ACT Hub, with a diverse array of state-of-the-art tools to explore HALF integration. WP 3 will explore the vital coupling of data and information relating to whole system planning and operational decision support, through the creation of a cyber physical architecture (CPA). This will generate new learning on current and future opportunities and risks, from a data and information perspective, which will lead to a whole system ontology for accelerated integration of hydrogen technologies. WP 4 considers options for a future energy system with HALF from a number of perspectives. The first is to consider expert views on HALF energy futures, and the public perceptions of those views. The second perspective considers place-based options for social benefit in HALF energy futures. The third perspective is to consider regulatory and policy options which would better enable HALF futures. Embedded across the research programme is the intent to create robust tools which are investment-oriented in their analysis. A Whole Systems and Energy Systems Integration approach is needed here, in order to better understand the interconnected and interdependent nature of complex energy systems from a technical, social, environmental and economic perspective. The Hub is led by Prof Sara Walker, Director of the EPSRC National Centre for Energy Systems Integration, supported by a team of 16 academics at a range of career stages. The team have extensive experience of large energy research projects and strong networks of stakeholders across England, Wales, Scotland and Northern Ireland. They bring to the Hub major hydrogen demonstrators through support from partners involved in InTEGReL in Gateshead, ReFLEX in Orkney, and FLEXIS Demonstration in South Wales for example. We shall engage to create a vibrant, diverse, and open community that has a deeper understanding of whole systems approaches and the role of hydrogen and alternative liquid fuels within that. We shall do so in a way which embeds Equality, Diversity and Inclusion in the approach. We shall do so in a way which is a hybrid of virtual and in-person field work consultation and develop appropriate digital tools for engagement.

Hydrogen and alternative liquid fuels (HALF) have an essential role in the net-zero transition by providing connectivity and flexibility across the energy system. Despite advancements in the field of hydrogen research both in the physical sciences and engineering, significant barriers remain to the scalable adoption of hydrogen and alternative liquid fuel technologies, and energy services, into the UK's local and national whole system infrastructure. These are technical barriers, organisational barriers, regulatory and societal barriers, and financial barriers. There are, therefore, significant gaps between current levels of hydrogen production, transportation, storage, conversion, and usage, and the estimated requirement for achieving net-zero by 2050. To address this, our proposed research programme has four interlinked work packages. WP1 will develop forward-thinking HALF technology roadmaps. We will assess supply chain availability and security. Selected representative HALF use cases will be used to identify and quantify any opportunities, risks and dependencies within a whole systems analysis. We will also develop an overarching roadmap for HALF system integration in order to inform technology advancement, industry and business development, as well as policy making and social interventions. WP2 will improve HALF characterisation and explore urgent new perspectives on the energy transition, including those related to ensuring resilience and security while also achieving net-zero. We will contrast the energy transition delivered by real incentives/behaviour versus those projected by widely-used optimisation models. The WP provides the whole systems modelling engine of the HI-ACT Hub, with a diverse array of state-of-the-art tools to explore HALF integration. WP 3 will explore the vital coupling of data and information relating to whole system planning and operational decision support, through the creation of a cyber physical architecture (CPA). This will generate new learning on current and future opportunities and risks, from a data and information perspective, which will lead to a whole system ontology for accelerated integration of hydrogen technologies. WP 4 considers options for a future energy system with HALF from a number of perspectives. The first is to consider expert views on HALF energy futures, and the public perceptions of those views. The second perspective considers place-based options for social benefit in HALF energy futures. The third perspective is to consider regulatory and policy options which would better enable HALF futures. Embedded across the research programme is the intent to create robust tools which are investment-oriented in their analysis. A Whole Systems and Energy Systems Integration approach is needed here, in order to better understand the interconnected and interdependent nature of complex energy systems from a technical, social, environmental and economic perspective. The Hub is led by Prof Sara Walker, Director of the EPSRC National Centre for Energy Systems Integration, supported by a team of 16 academics at a range of career stages. The team have extensive experience of large energy research projects and strong networks of stakeholders across England, Wales, Scotland and Northern Ireland. They bring to the Hub major hydrogen demonstrators through support from partners involved in InTEGReL in Gateshead, ReFLEX in Orkney, and FLEXIS Demonstration in South Wales for example. We shall engage to create a vibrant, diverse, and open community that has a deeper understanding of whole systems approaches and the role of hydrogen and alternative liquid fuels within that. We shall do so in a way which embeds Equality, Diversity and Inclusion in the approach. We shall do so in a way which is a hybrid of virtual and in-person field work consultation and develop appropriate digital tools for engagement.

The EPSRC Centre for Doctoral Training (CDT) in Engineering Hydrogen Net Zero will develop the necessary networking, training and skills in future doctoral level leaders to enable rapid growth in hydrogen-related technology to meet the UK government's 2050 net zero targets. This CDT is a partnership of three world class Universities and around 40 Industrial and Civic organisations. The CDT aims to address the challenging aspects of rapid growth in hydrogen production and usage such as cost, supply and waste chain development, scalability, different system configurations, new technology, and social requirements through a blended cohort co-creation approach. The CDT will provide mandatory and optional training in Fundamental Knowledge, Thinking Innovatively, Business Acumen and Equity, Diversity, Inclusion, and Community (EDIC). A cohort based CDT is most appropriate for embedding skills in Engineering Hydrogen Net Zero due to the breadth of the training needs and the need for co-support and co-learning. In addition to a tailored co-created skills training program, the CDT will engage with partners to address key research priority areas. The CDT research plans are aligned with the EPSRC's "Engineering Net Zero" research priority, aiming to engineer low-cost hydrogen for net zero. Decarbonisation is not just implementation of a single solution fits all but a complex process of design that is dependent on what is being decarbonised e.g. different types of chemical industry to whether or not there is future access to a hydrogen hub. This results in the requirement for many new solutions to ensure affordability, scalability and sustainability. This includes undertaking research on hydrogen into topics such as, design for scalability, hydrogen on demand, new low cost materials, new interfaces, new processes, new storage means, new energy interactions, new waste management, existing infrastructure adaption and lifespan monitoring and management and social acceptance. The CDT will work with industry and civic partners to generate impact through innovation through research. This will include direct financial benefits, improved policy outcomes through engagement with local authorities, government organizations, and standards bodies, enhanced public engagement and acceptance of hydrogen, and create employment opportunities for students with industry-ready skills. The CDT represents an excellent opportunity for students to work together, with industry and with world leading international experts on impactful projects for a common decarbonisation goal with multifunctional stakeholders. This CDT will build upon the experience of the University partners and the lessons learnt from participation in 7 previous CDT's to bring forward best practice (e.g. buddy scheme and childcare funding) and remove roadblocks to opportunities (e.g. timetable clashes). We will co-create a CDT with international reach and access to over £55m worth of hydrogen and wind turbine demonstrator and research facilities. The team has excellent links with Universities and Industry internationally including partners in Europe, Canada, Malawi, China, USA, Brazil and Australia. CDT students will have opportunities to learn from International experts at a summer design and build, link with world leading experts to build international networks of contacts, undertake CPD activities (such as partner site visits), attend national and international conferences & partners secondments, research sandpits and webinars. All activities will be undertaken with due care, diligence & best practice in EDIC. The academic, industrial and civic team has the expertise to deliver the vision of the co-created CDT through the development of a unique research and training program.