Energy storage in bricks? Germany launches innovative project.
In Brunsbüttel, Schleswig-Holstein, one of Europe’s most innovative industrial projects has begun, combining the energy transition with the decarbonization of production processes. Covestro and Rondo Energy, in the presence of political and business representatives, officially inaugurated the construction of the Rondo Heat Battery – a high-temperature heat battery designed to supply process steam without using fossil fuels.
A response to renewable energy variability
The Rondo Heat Battery is designed to address one of the key challenges of the energy transition: the variable availability of renewable energy. The system charges during periods of surplus cheap electricity from renewables, storing it as heat in special bricks. The stored energy is then used to produce high-temperature steam required for continuous industrial processes.
This ensures a stable supply of thermal energy regardless of weather conditions or fluctuations in renewable energy generation, providing a real alternative to conventional natural gas boilers.
A strategically important project for the region
The importance of the investment is highlighted by regional authorities. Tobias Goldschmidt, Minister for Energy Transition, Climate Protection, Environment, and Nature in Schleswig-Holstein, emphasized that the project fits perfectly into the region’s long-term strategy:
“The energy transition is the project of our time. The dynamic growth of renewable energy strengthens Schleswig-Holstein’s economic attractiveness and enables the implementation of forward-looking solutions, such as industrial heat storage. Projects like this support energy sovereignty and the achievement of climate neutrality goals.”
100 MWh of heat and tangible emission savings
The planned 100 MWh heat battery is scheduled to begin operation by the end of 2026. The project is supported by Breakthrough Energy Catalyst and the European Investment Bank. Once operational, the installation will cover about 10% of Covestro’s process steam demand in Brunsbüttel, allowing for a reduction of up to 13,000 tons of CO₂ per year.
For Covestro, operating in the chemical sector, steam is a critical part of the production process and one of the main sources of energy consumption. Currently, steam in Brunsbüttel is still generated from natural gas, making the new installation an important step toward decarbonizing the plant.
Traditional materials in modern technology
The Rondo Heat Battery combines the simplicity of proven solutions with modern automation. Bricks, used for centuries as heat storage in metallurgy, become the core of an advanced energy system. The heat stored in the bricks powers a standard boiler that produces completely emission-free steam when renewable electricity is used.
“This is an example of technology that allows us to test and implement solutions that bring us closer to a circular economy and climate-neutral production,” says Dr. Thorsten Dreier, Covestro’s Chief Technology Officer.
Industry and grid stabilization in one
According to Rondo Energy, the project has significance beyond a single plant. Eric Trusiewicz, CEO of the company, notes that industrial heat storage can simultaneously support European industrial competitiveness and the stability of power systems.
“Europe increasingly experiences periods of excess cheap renewable energy, while industry needs reliable and affordable energy sources. This project shows that clean industrial heating can be stable, cost-effective, and act as a grid-balancing tool,” Trusiewicz emphasizes.
Pilot project before scaling
Covestro treats the Brunsbüttel installation as a pilot project. Based on operational experience, the company will decide whether the Rondo Heat Battery technology can be deployed on a larger scale at other plants. If the pilot succeeds, the solution could become a key component of decarbonizing energy-intensive industry in Europe.