Covestro is partnering with Rondo Energy to install an innovative heat battery for the first time. The Rondo heat battery stores intermittent renewable electricity and delivers continuous high-temperature steam, thus offers 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 ten percent 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.

The heat battery stores electrical energy, using bricks that have been used for heat storage at steel mills for centuries. Image courtesy of Rondo Energy.  

“Rondo Heat Batteries deliver deep decarbonization by changing the fuel, not the factory,” said Eric Trusiewicz, CEO of Rondo Energy. “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.”