Heat pumps and the requirement for grid-scale energy storage in the UK

In this paper we study the effect that the electrification of heat demand through the use of air-source heat pumps could have on a future zero-carbon electricity grid in the UK and the requirement for grid-scale energy storage. The study considers different adoption levels of heat pumps, going from 0 to 100% of UK homes. For each penetration level, we analyse different mixes of wind and solar, different levels of over-generation and different combinations between medium and long duration energy stores (hydrogen and compressed air, respectively) to determine the configuration that minimises the total cost of electricity (TCoE). TheTCoEincreases ~4% as the heat pumps’ uptake goes from 0 to 100%, owing to the greater storage capacity needed by the system. If heat pumps are adopted in 100% of UK homes, the electricity grid will need 175 TWh of storage. Underground hydrogen caverns provide 160 TWh (~220 days) while CAES systems provide 15 TWh (~10 days). Batteries (required for short duration imbalances) are not considered in the study. In this scenario, wind supplies 95% of the electricity and the lowestTCoEachieved is 74.5 £/MWh. The cost of electricity will be higher once short duration storage is accounted for.