Question to the Department for Energy Security & Net Zero:

To ask the Secretary of State for Energy Security and Net Zero, what assessment his Department has made of the potential contribution of heat battery technology to the Warm Homes Plan; and what steps he is taking to support the (a) development and (b) deployment of heat batteries in domestic heating systems.

Heat batteries are a promising technology because they utilise time-of-use tariffs, do not require outside space, and can be cheaper to install than heat pumps in some circumstances. However, they are also less efficient than heat pumps and will therefore use more energy to meet the same heating demand.

The Department is exploring, through studies like the Homes for Net Zero Trial, the role heat batteries could play in the future. We will continue to review our position on heat batteries as the supporting evidence base develops.