In a significant step toward climate-neutral manufacturing, Covestro and Rondo Energy have officially broken ground on a first-of-its-kind industrial heat battery at Covestro’s Brunsbüttel site in Germany.
Scheduled to go into operation by the end of 2026, the 100 MWh Rondo Heat Battery (RHB) is designed to capture intermittent renewable energy from the grid when prices are low and convert it into a continuous supply of high-temperature steam. This brick-and-iron technology effectively eliminates the green premium by providing a reliable, cost-effective alternative to natural gas for heavy industry.
The heat battery technology:
The technology behind the heat battery project combines centuries-old materials with cutting-edge automation. At its core, the battery uses refractory bricks—similar to those used in steel mills for generations—to store electrical energy as intense heat. This stored thermal energy then drives a conventional boiler to produce emission-free steam at temperatures exceeding 1,000°C. Once operational, the system will supply roughly 10% of the site’s total steam demand, cutting carbon dioxide emissions by up to 13,000 tons annually.
Thought leadership:
The project has garnered significant support from European financial institutions and regional government leaders. Dr. Thorsten Dreier, CTO, Covestro, highlighted the project’s role in the company’s long-term vision. “As an innovation company, we are always excited when we can further develop and test promising ideas that can bring us closer to our goals of a circular economy and climate-neutral production. The heat battery is such an idea: a new technology that enables us to take another step forward on our path to a sustainable future.”
Eric Trusiewicz, CEO, Rondo Energy, emphasized the dual benefit for the European energy landscape. “This project shows how two of Europe’s central challenges can be solved together. Together with Covestro, we are demonstrating that clean industrial heat can be both highly reliable and a powerful tool for balancing the grid — while building the energy infrastructure needed to strengthen Europe’s industrial base and energy security.”
Strengthening regional energy sovereignty:
Located in the state of Schleswig-Holstein, a region known for its high wind power generation, the project serves as a model for how volatile renewable energy can be harnessed for stable industrial use. Tobias Goldschmidt, the state’s Minister for Energy Transition, praised the initiative as a booster for the local economy, noting that such projects are essential for achieving Germany’s 2045 climate neutrality goals while maintaining industrial competitiveness.
