THISTLES will look to test thermal batteries as an alternative to heat pumps and explore how best to integrate them into flexibility markets to reduce network pressures.

Benefits

This project is categorised as a Research project; however, an indicative benefit pathway has been considered based on the counterfactual scenario. 
Base Cost (Counterfactual): In the absence of heat battery deployment, homes unsuitable for heat pumps or heat networks will continue to rely on fossil fuel heating, leading to higher carbon emissions, poor air quality, and limited flexibility for the electricity system. Electrification of these homes using direct electric heating would increase peak demand and require costly network reinforcement, particularly in constrained LV areas. Additionally, vulnerable consumers in these homes may face higher energy bills and limited access to decarbonisation support. 
Method Cost (THISTLES): The proposed solution leverages smart heat batteries that can charge during off-peak periods and provide controllable, high-temperature heating without requiring major infrastructure upgrades. By smoothing demand and enabling participation in flexibility services, heat batteries reduce the need for reinforcement and improve network efficiency. The technology is cost-comparable to gas boilers and heat pumps, but with lower servicing costs and better alignment with consumer needs in hard-to-decarbonise homes. 
 
A high-level calculation suggests that, if deployed at scale, heat batteries could deliver significant benefits, these benefits will be calculated during the project, including a CBA to corroborate initial assumptions. 
 
Recipients of the benefit include: 
Consumers, through lower energy bills, improved indoor air quality, and access to clean heat. 
Network operators, through deferred reinforcement, improved LV network utilisation, and enhanced flexibility. 
The wider system, through reduced emissions, better integration of renewables, and support for a just transition.