Assessing the ability of electrified domestic heating in the UK to provide unplanned, short-term responsive demand

The ability of UK housing equipped with heat pumps to provide responsive electrical demand at scale has been analysed using building simulation and a representative sample of individually-attributed dwelling models. The predictions of the models were verified against national data. The response of the stock (constrained by local thermal comfort and hot water needs) to a signal requesting load variation was tested using annual simulations. Results indicated that an overall median of 43% of heat pumps could respond in some way to a drop load signal, and 70% to a pick-up load signal. Response for longer durations of up to 4 h, as required by some grid services, was significantly less, reducing nearly linearly as signal duration increased. Scaled to the UK housing stock (approx. 27 million dwellings), the results suggested a median response of 2 GW to a drop load signal, and 4.7 GW to a pick-up load signal. These figures mask large diurnal and seasonal differences in the ability to respond to load variation requests, with greater response during periods of heat pump usage in mornings and evenings and during the heating season. Conversely, during periods of limited heating demand, the ability to respond to signals was limited.