Rondo Energy commissions world’s largest industrial heat battery

Rondo Energy has started commercial operation of a 100 MWh industrial heat battery, described by the company as the world’s largest, at a fuel production facility in California. The system generates continuous high-pressure steam powered entirely by on-site wind and solar energy, providing a model for round-the-clock, low-carbon industrial heat.

The unit began operations in October 2025 after two months of automated testing verified performance and safety. Operating above 1,000°C with over 97% efficiency, it required no modification to existing steam systems. The project recorded no safety incidents during construction.

Rondo’s electric thermal storage system stores heat in durable, widely available materials such as brick and wire. It charges for about six hours daily using low-cost electricity from on-site renewables or the grid during off-peak hours, then delivers continuous heat or steam. This allows energy-intensive industries to maintain steady operations while shifting to renewable energy sources.

Inside the battery, electric current heats stacked bricks to over 1,000°C. Air flow transfers this stored heat to produce steam for industrial use. The non-toxic, fire-safe design avoids rare minerals and can integrate with existing process lines.