World’s largest industrial heat battery debuts

October 19, 2025

Rondo Energy has officially launched full-scale commercial operations of what it calls the world’s largest industrial heat battery system. The groundbreaking 100 MWh thermal storage unit is now operating at a Holmes Western Oil facility in California, running entirely on renewable solar power from an on-site array.

This project demonstrates how renewable energy can supply continuous, high-pressure steam and heat for heavy industrial processes—marking a major milestone in the global effort to decarbonize energy-intensive manufacturing sectors.

A breakthrough in industrial thermal energy

The Rondo Heat Battery captures and stores solar energy during the day, then delivers consistent, high-temperature heat 24/7. During a 10-week performance test, the system achieved over 97% round-trip efficiency while sustaining temperatures above 1,000°C (1,832°F).

According to Rondo, the 100 MWh heat battery generates as much usable heat as 10,000 home heating systems combined.

“The Rondo Heat Battery is now proven at industrial scale,” said Rondo CEO Eric Trusiewicz.
“We’re already deploying and operating heat batteries across four continents and five industries. Our customers are improving their competitiveness while dramatically cutting carbon emissions.”

The system operates seamlessly alongside existing gas-fired boilers, channeling steam through the same infrastructure with no retrofitting required. By using locally produced solar energy to replace natural gas, Holmes Western Oil can stabilize energy costs, reduce carbon exposure, and increase energy independence.

How it works: simple, scalable, and sustainable

Industrial heat production accounts for nearly one-quarter of global energy demand, traditionally fueled by coal, oil, and gas. Rondo’s innovative system provides a clean, efficient alternative—built from simple, durable materials.

Unlike electric boilers or heat pumps that require constant power, the Rondo Heat Battery only needs to charge for about six hours per day, using low-cost or off-grid renewable electricity. Once charged, it delivers continuous, high-pressure heat—even through the night.

“Just as electric vehicles unlocked transportation for renewable energy, heat batteries will do the same for industrial heat,” said Andy Lubershane, Partner at Energy Impact Partners. “It’s a global turning point for solar and wind integration.”

The system’s design—bricks and wires, no rare minerals—eliminates fire risks, toxic leaks, and resource bottlenecks, offering a safer and more sustainable solution. It can deliver steam at pressures exceeding 100 bar (1,450 psi) and integrate easily into existing infrastructure, accelerating the shift to clean industrial energy.

Global expansion and a path to net-zero industry

Backed by Breakthrough Energy Ventures, founded by Bill Gates, and Energy Impact Partners, Rondo Energy is now scaling its technology worldwide. The company is developing commercial projects across North America, Europe, Asia, and Australia.

The key to Rondo’s scalability lies in its use of abundant, low-cost materials rather than specialized components—allowing rapid deployment across multiple industries.

As global manufacturers seek reliable, renewable energy solutions to meet net-zero targets, Rondo’s heat battery offers a cost-effective, high-performance pathway to carbon-free industrial heat.