The UK has made considerable progress decarbonising its power sector. However, decarbonising space-heating has been much more challenging. Currently, space-heating accounts for ~1/3 of the country's CO2 emissions. This must change to achieve Net Zero Two main low-carbon heating solutions are being considered: 1) direct heating from hydrogen combustion in boilers and 2) electrically-driven heat-pumping. Although both are promising, there are serious challenges to overcome. National Grid and other gas network operators have confirmed the technical feasibility of distributing hydrogen through the existing gas infrastructure, which connects >23 million properties. Hydrogen boilers are not commercially available yet, but they are well underway. Hydrogen can be made from renewable electricity; however, a big downside is that when combusted in boilers, the amount of energy we recover is only ~60% of what we spent making it. It is not a very efficient process. Electric heat pumps have a much higher efficiency. The amount of heat they provide can be as much as 3x the amount of electricity they consume. So, for every 1kWh of electricity used, a heat pump will give 3kWh of heat. This in stark contrast to the 0.6 kWh that would be obtained if the same 1kWh of electricity was used to make hydrogen, and that hydrogen was combusted in a boiler. Although it seems like using electric heat pumps is the way to go, there is a major problem. The electricity grid does not have the capacity to support their use in any significant fraction of UK homes. The reason for this is the huge energy demand for heating purposes. During winter, the peak demand in the gas network is more than 4x than the peak demand in the electricity grid. But also, during the first few hours of each day, the gas network experiences power-ramps that are 10x greater than what the electricity grid sees. The electricity grid does not have the capacity to provide the same levels of energy and power as the gas network. The upgrades required to enable the electricity grid to take on the gas network's duty are too expensive to be viable. It is precisely these challenges that are holding back the UK's transition to low-carbon heating. This postdoctoral fellowship addresses this issue by investigating and developing a deep understanding of a novel set of technologies called 'High-Performance Heat-Powered Heat-Pumps (HP3)'. These innovative heating systems combine the best attributes of the two main low-carbon options being considered (hydrogen boilers and electric heat pumps) and at the same time, removes their drawbacks. The widespread adoption of HP3 systems will enable the gas network to distribute hydrogen to homes across the country and therefore to continue to supply the enormous demand for energy during winter. HP3 systems deliver a greater benefit per unit of H2 consumed in comparison to hydrogen boilers. This will help the gas network to supply hydrogen to even more homes but also, consumers will enjoy reduced bills. By keeping the gas network in service, the use of HP3 systems will avoid placing an overwhelmingly large load on the electricity grid that would be created if the country adopted electrically-driven heat-pumping. This fellowship will develop detailed computational models to simulate the operation of HP3 systems in order to understand the effect that different design and operational variables have on their performance. Special focus will be given to exploring ultra-high operating pressures at this can lead to reductions in the overall cost of the units. A laboratory prototype will be developed and tested to demonstrate the functionality concept. This work has real prospects to be transformational in two different ways: (i) triggering a step-change in the UK 'boiler industry' towards more sophisticated and much higher-value products and (ii) accelerating the achievement of Net Zero by improving affordability.

This project will assess the potential value of hydrogen to the UK as part of a transition to a low carbon economy. It will assess the potential demand for and value of hydrogen in different markets across the energy system and will analyse the supply chain required to produce and deliver that hydrogen, including the supply of hydrogen from using electrolysers for load balancing in the UK electricity system with a high penetration of renewable electricity. In the short-term, hydrogen electrolysers can support electricity system load balancing as the proportion of intermittent renewables increases. The Universities of Edinburgh and Reading have led efforts to characterise the UK wind power resource and to understand how new developments can be incorporated into the UK electricity system. This project will extend the models developed at these institutions to assess the indirect value of hydrogen in supporting a high penetration of renewable electricity by avoiding electricity network reinforcement. It will also link these models with the UK energy system model at UCL (UK TIMES) to assess the direct value of electrolysed hydrogen to companies, if the hydrogen is used in the gas network (power-to-gas), as an industrial feedstock, as a transport fuel or for large-scale storage as part of the electricity system. The models will identify the most appropriate locations for electrolysis deployment and the timescales on which they should be deployed. In the medium-term, the most important use of hydrogen is likely to be in the transport sector. UCL has recently examined how a hydrogen supply chain might develop across the UK using a new spatially-explicit infrastructure planning model called SHIPMod. This project will add a number of new features to this model including hydrogen pipelines and finer temporal disaggregation to link with the electrolysis parts of the network models developed at Edinburgh. It will be used to assess the value of hydrogen supply infrastructure and will identify the optimum deployment of infrastructure across the UK. In the longer term, hydrogen is a zero-carbon option to replace natural gas for heat generation. UCL have examined the potential for converting the natural gas networks to use hydrogen and to examine the long-term prospects for micro-CHP to replace boilers. This project will build on this research with the aims of: (i) assessing the value of hydrogen to the UK for heat provision; (ii) understanding the impact of hydrogen on the gas distribution networks; and, (iii) examining how using hydrogen for heat as well as transport would impact the development of a hydrogen supply infrastructure. Hydrogen infrastructure represents a risky investment in the early stages of a transition because of the highly uncertain future uptake of hydrogen vehicles. It is important to factor the cost of this risk into the value of hydrogen. We will use a mixture of real options and stochastic programming analysis, using the UK TIMES energy system model and the SHIPMod infrastructure planning model, to account for and manage risk in different scenarios (including using hydrogen only for transport or using it for both transport and heat). Hence we will identify scenarios with lower investment risk and we will identify policies that will reduce these risks and facilitate the development of a hydrogen economy. This project will build on existing research projects, including using models developed by the EPSRC H2FC Supergen Hub and the EPSRC Adaptation and Resilience in Energy Systems (ARIES) project. Funding for hydrogen research in the UK is currently almost exclusively focused on technology development and this project will fill an important gap in the funding landscape by taking a whole systems approach to understanding the potential role of hydrogen in future UK low-carbon energy system configurations.