Carnot Batteries are an emerging technology for the inexpensive and site-independent storage of electric energy at medium to large scale. Also referred to as “Pumped Thermal Electricity Storage” (PTES) or “Pumped Heat Storage” (PHES), a Carnot Battery transforms electricity into thermal energy, stores the thermal energy in inexpensive storage media such as water or molten salt and transforms the thermal energy back to electricity as required.
Reaching from medium to high capacities up to 100MW/1000MWh, Carnot Batteries have the potential to solve the global storage problem of renewable electricity in a more economic and environmentally friendly way than conventional batteries.

Although several concepts have been proposed for Carnot Batteries, a comprehensive techno-economic assessment of this technology has yet to be developed. Only a few laboratory or plant-scale demonstration facilities exist that provide the energy storage community with scientific data. The establishment of an international platform to bring together experts from industry and academia in a structured way, that assesses the state of the art of R&D for Carnot Batteries, deepens the understanding of their possible role in the future energy system and makes Carnot Batteries internationally visible would greatly strengthen the community.

The overarching aim of this Task is to ease the transition from a fossil-fuel based to a renewable source based energy system, through the promotion of novel energy storage systems, assisting their development, deployment, demonstration and their deep understanding.
Therefore, this Task aims to stablish a platform that brings together experts from the industry and academia, to systematically investigate, assess and strengthen the potential role of Carnot Batteries in the future energy systems.
The key objectives of Task 36 are:

• Mapping of the main Carnot Batteries technologies and applications through the collection of existing information on electricity storage systems based on thermal energy storage.
• Developing technology Key Performance Indicators of the Carnot Battery systems and their key components.
• Critical assessment of technological competitiveness and R&D demand.
• Help technology to market and delimit its market reach by identifying the services that should/can be provided by Carnot Batteries.
• Inform policy and provide a basis for proper regulations, based on the benefits and potential of Carnot batteries and the requirements to assist their deployment.
• International dissemination of the technologies through workshops, white paper, open source datasets and scientific papers.

The final report of the Task 36 can be accessed here.