How does a Carnot battery work?

The growth of renewable energy requires flexible, low-cost and efficient electrical storage to balance the mismatch between energy supply and demand. The Carnot battery buffers electrical energy by storing thermal energy (charging cycle mode) from a resistive heater or a heat pump system when the electricity production is higher than the demand.

Can a Carnot battery store electricity at a low cost?

There is a need for large scale electrical energy storage. The Carnot battery allows to store electricity at low cost with no geographical constraints. Each configuration of Carnot battery is described. A comparison is proposed including a state of the art, potential on the energy market and existing prototypes.

Is liquid air energy storage a Carnot battery?

Although Liquid Air Energy Storage (LAES) has often been considered merely an advancement of CAES [12,72] proposed to improve energy density, LAES is based on different physical principles. As was discussed, LAES stores electrical energy as heat, and not as mechanical energy, hence it should be considered a proper Carnot battery.

How can a Carnot battery be improved?

A Carnot battery performance may be improved by using additional thermal energy inputs in the charge or discharge phases, but this should not change its primary purpose, which is storing electric energy. Similarly, a Carnot battery may produce both electric energy and useful thermal energy.

Is a LAEs Battery A Carnot battery?

As was discussed, LAES stores electrical energy as heat, and not as mechanical energy, hence it should be considered a proper Carnot battery. To store electrical energy, LAES exploits the liquefaction of air, which is a convenient way to store latent heat. Liquefied air is produced cryogenically, at -196°C, which is the boiling point of nitrogen.

Are Carnot batteries a cost-effective energy storage solution?

In the increasing need of medium and long duration energy storage, Carnot batteries (CB) offer a potentially cost-effective solution with systems ranging from large grid scale applications down to even dozens of kW. Therefore, the concept has attracted not only academic, but already also considerable industrial, research and development.