Heat Pumps vs Hydrogen Boilers: Weighing Up the Options for the Decarbonisation of Heating in the United Kingdom

Space heating contributes a quarter of the United Kingdom’s carbon footprint and presents a significant challenge to the attainment of the country’s net zero status. Among the decarbonisation options, the use of heat pumps, powered by wind and solar electricity, and gas heaters, supplied with green and blue hydrogen, are particularly suitable. Using a model of the country’s energy system, developed from real time data and allowing for an examination of the robustness of the two options under extreme events, we show that both options, referred to as High Electricity and High Hydrogen respectively, have real constraints for which there are as yet no practical solutions. High Electricity will be a costly option reliant on extensive retrofitting of the present housing stock and a wind fleet three times larger than the present fleet, presenting problems for grid stability. On the other hand, High Hydrogen, which assumes significant use of blue hydrogen, will be unrealistic unless the existing technologies for carbon capture and storage can be radically improved, and the necessary supplies of natural gas can be assured. Both options are also vulnerable to extreme events, as revealed by the dynamic modelling, suggesting that a more detailed system design, based on dynamic simulations, will be essential before any final decision can be taken.