New 100 MWh industrial battery uses bricks to store heat, supplies steam

US-based Rondo Energy and Covestro have initiated construction of a 100 MWh industrial heat battery at Covestro’s chemical site in Brunsbüttel, northern Germany, aiming to produce reliable steam without fossil fuels. Scheduled to be operational by the end of 2026, the system converts surplus renewable electricity—particularly during periods of low demand and negative electricity prices—into stored heat within specially designed bricks. This stored thermal energy can then generate high-temperature steam on demand, replacing fossil-fuel-fired boilers and reducing carbon emissions. The project is supported by Breakthrough Energy Catalyst and the European Investment Bank, reflecting strong investor confidence. The heat battery is expected to supply about 10% of the site’s steam needs, potentially cutting CO2 emissions by up to 13,000 metric tons annually. This partial electrification of heat at a continuously operating chemical facility demonstrates meaningful climate benefits and serves as a model for scaling electrified heat in energy-intensive industries. The technology leverages the simplicity and reliability