Carnot batteries

Low-cost and location-independent energy storage in the gigawatt hour range

Given the increasing share of fluctuating renewable energy in power generation in Germany and across the world, there is a growing need to cost-effectively store large amounts of electrical energy over several days. Today and for the foreseeable future, battery storage is too expensive and their cycle lives are too poor for such purposes. Synthetic carbon-neutral fuels that are converted into energy in gas-turbine power plants possess the highest energy density of any energy storage system. However, their production requires huge quantities of biomass, which cannot be provided in suffcient amounts today or any time soon.

According to Robert Laughlin (Stanford University), winner of the Nobel Prize in Physics, power-heat-power storage units (known as Carnot batteries) will be the key technology for storing large quantities of energy in a carbon-neutral energy system of the future. In a Carnot battery, energy is converted into heat at a temperature between 90°C and 500°C by using a high-temperature heat pump. This heat is stored inexpensively in water (90°C) or molten salt (500°C) and reconverted into energy through a thermal power process, when required. A valuable added beneft of Carnot batteries is their ability to supply heat and cooling in addition to stored energy. The possibility of providing cooling is particularly important for decarbonisation in countries such as India and China.

The DLR Institute of Engineering Thermodynamics is a scientifc pioneer in the energy storage industry and has the ideal capabilities for the development of Carnot batteries thanks to its many years of experience in the feld of high-temperature heat storage.

Since 2014, DLR and the University of Stuttgart have been working intensively on concepts for Carnot batteries and, together with the Karlsruhe Institute of Technology, are setting up the NADINE research infrastructure, which will allow Carnot batteries to be demonstrated and put to industrial use.

German Aerospace Center (DLR)
Andre Thess · E-Mail: ·