Covestro and Rondo Energy have recently marked the groundbreaking of an innovative heat battery at Covestro’s Brunsbüttel site in northern Germany. The Rondo Heat Battery stores surplus low-cost renewable electricity as heat in specially designed bricks and converts it into continuous high-temperature steam for industrial processes, offering a fossil-free alternative to conventional steam generation.

The project has been highlighted by the Government of Schleswig-Holstein as a key milestone in its climate-neutral transition, underlining the role of renewable energy expansion in supporting future-ready industrial investments.

The 100 MWh heat battery is scheduled to become operational by the end of 2026 and is supported by Breakthrough Energy Catalyst and the European Investment Bank. Once commissioned, it is expected to supply around ten per cent of the site’s steam demand and reduce carbon dioxide emissions by up to 13,000 tonnes annually.

Covestro said the project aligns with its strategy to advance circularity and climate-neutral production, while Rondo Energy noted that the system demonstrates how clean industrial heat can also help balance electricity grids with rising renewable penetration. Based on performance at Brunsbüttel, Covestro is assessing the potential for wider deployment of the technology across its operations.