• Energy Research

Transitioning from predominantly natural gas domestic heating to low carbon heating is one of the major challenges of the UK’s net zero decarbonisation pathway. Compact wall-hung combination boilers are the dominant heating appliance and continue to be installed as a rate of over 1.5 million per year, compared to less than 50 k per year for Heat Pumps. The disparity persists despite repeated Government support in the form of the Renewable Heat Incentive and the Green Homes Grant. Compact hybrid appliances offer a technology solution similar to the current combination boiler in terms of size and performance, which could be attractive to consumers. However, there is currently little knowledge of the emissions savings that could be achieved in practice by compact hybrid appliances. This research systematically analyses real world high frequency boiler data to evaluate the potential of such appliances to make carbon savings while emulating combination boiler operation. By utilising high frequency diagnostic data from combination boilers, the disaggregated (hot water and heating) demand is mapped onto hybrid models to determine the energy and emission impact. Exploration of the relative power output of the HP and boiler components of the modelled hybrid appliances provides insight into the appropriate specification of compact hybrids which can deliver similar heat service to boilers while maximising emissions savings. The analysis shows that hybrid appliances with moderately sized HPs can significantly contribute to the decarbonisation of the homes considered in the study. Considerable disruption could be avoided in retrofit due to the physical size of the proposed heat pump and ability of the hybrid system to operate with the existing heat emitter network.

This paper investigates the impact of locational pricing on the roll out of heat pumps in the UK. Qualitative assessment of proposals set out for electricity market reform in the UK identified locational pricing as potentially having an impact on heat pump running costs. Energy system modelling was used to assess the economics of both individual heat pumps and system-wide heat pump roll out under both unified pricing and locational pricing for the UK for 2020 and 2035. PyPSA-GB, a future power system model, was employed to simulate unified and locational wholesale prices and the Octopus Agile tariff was used to calculate indicative retail tariffs applicable to domestic heat pumps. The research highlights that locational pricing can create market conditions which better reflect the true cost of generating and delivering electricity, however, it can also lead to higher heat pump operating costs in regions with projected high heat demand. Key findings reveal that locational pricing could result in significant geographical disparities in heat pump operating costs due to varying electricity prices across different zones. Further work is required to develop policy to alleviate high operating costs and to promote flexible operation of heat pumps.

Abstract Heating homes using gas boilers is incompatible with the UK’s target of net-zero greenhouse gas emissions by 2050. One solution is to shift to heat pumps (HPs) supplied from decarbonised power plant, but this could place an unmanageable burden on the electricity supply network. National heat demand profiles depend on the heating patterns adopted by households which, in turn, depend on the type of heating system and its control. The largest data sets available, from around 6600 gas-heated homes and 600 homes with HPs, are used to create an empirical model of Great Britain’s (GB) half-hourly domestic heat demand. The model is used to estimate the annual half-hourly heat demand of the GB housing stock for both current and future weather conditions. The demand profile when using HPs is compared to the current profile for gas heating. In a cold year, the calculated total annual heat demand of a typical mix of ground source and air-source HPs was 422TWh, 8% greater for than for gas-heated homes. However, the peak heat demand of 157GW was 8% lower than for gas heating, and the maximum heat ramp rate of 21GW/h, 67% lower. These results are due to the different ways that households use gas boilers and HPs. The accurate modelling of heating patterns is necessary to achieve reliable predictions of national heat demand. Policy initiatives, financial incentives or other interventions that influence the daily pattern of HP usage could also have a marked and positive influence on the GB heat demand profile.