The 100MWh Rondo heat battery.
Commercial operation started in October 2025 after over two months of automated testing that confirmed performance, reliability, and safety. The installation was completed without modifications to existing steam systems. The unit operates above 1,000°C with more than 97% thermal efficiency and recorded no safety incidents during construction or commissioning.
Based in California, Rondo Energy specializes in developing electric thermal storage systems that store heat in durable materials such as brick and wire. The company is expanding similar projects across North America, Europe, Asia, and Australia to help energy-intensive industries reduce emissions and lower energy costs through renewable heat technologies.
Industrial heat generation currently accounts for about one-quarter of global energy demand, with sectors such as steel, cement, and chemicals depending heavily on consistent, high-temperature processes typically fueled by fossil energy. Rondo’s technology enables these industries to shift to renewable sources with minimal disruption to existing infrastructure.
The system functions by charging for roughly six hours a day using the most economical electricity available — either from on-site solar power or from the grid during off-peak periods. Once charged, it provides continuous heat or steam, effectively decoupling variable renewable electricity supply from industrial processes that require constant high-temperature energy.
Within the battery, an electric current heats stacked bricks to temperatures exceeding 1,000°C. The stored heat is then transferred through controlled airflow and converted into steam to support production operations. The system uses non-toxic, fire-safe materials and requires no rare minerals, allowing integration alongside existing boilers or process lines with minimal retrofitting.
Rondo Energy stated that its thermal battery offers industries a pathway to decarbonize while maintaining stable and cost-effective operations. By converting renewable electricity into stored heat for continuous use, the system provides a scalable solution to one of the most difficult challenges in the clean energy transition — replacing fossil-based heat in industrial production.
The successful launch of the California facility demonstrates how renewable energy and advanced storage technologies can work together to deliver reliable, high-temperature heat at industrial scale. Rondo Energy plans to apply the same approach globally, contributing to the wider adoption of clean energy solutions in manufacturing and heavy industry.
