Covestro is partnering with Rondo Energy to install an innovative heat battery at its site in Brunsbüttel, Germany. The Rondo Heat Battery stores intermittent renewable electricity and delivers continuous high-temperature steam, offering a sustainable alternative to steam generation with fossil fuels.

The Breakthrough Energy Catalyst foundation set up by Bill Gates and the European Investment Bank (EIB) are supporting this installation of the Rondo RHB100 heat battery, which is scheduled to begin operation at Covestro’s Brunsbüttel site at the end of 2026. The project will then produce 10% of the steam required at the site, saving up to 13,000 tons of CO₂ emissions per year.

Rondo Heat Batteries combine century-old materials and cutting-edge automation to capture electricity and deliver high-temperature heat and power. Electrical energy is stored as heat, using bricks that have been used for heat storage at steel mills for centuries. The heat powers an ordinary boiler to deliver zero-emission steam. Renewable electricity can be intermittently stored when there is an excess available and a constant amount of steam can still be generated continuously.

"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," said Dr. Thorsten Dreier, CTO of Covestro. "The heat battery is such an idea: a new technology that allows us to go one step further on our way to a sustainable future."

Eric Trusiewicz, CEO of Rondo Energy, commented "We’re honored to be working with Covestro to prove our safety, reliability, and efficiency under real conditions on a large scale over a long period of time. And we’re excited to be deploying in Brunsbüttel, where large flexible electricity loads are particularly valuable to the electricity grid."

For Covestro, steam generation is an important part of the production process and accounts for a large proportion of energy consumption. The learnings from this first heat battery installation will provide experience and insights for Covestro to be able to assess whether larger-scale deployments are possible.

Learn more about Covestro, visit www.covestro.com.