Rondo Energy

Rondo Energy was founded in 2020 in San Francisco, California by John O'Donnell (CEO) and Pete von Behrens. O'Donnell brings over 30 years of experience building energy technology companies: he previously co-founded Ausra, a pioneer in solar thermal electricity, and GlassPoint Solar, which delivered more than half of all the solar industrial heat deployed worldwide. In 2020, he and von Behrens began developing the Rondo Heat Battery in von Behrens’ garage in San Francisco — experimenting with stacking patterns for bricks to maximize heat conductivity. The company is headquartered in San Francisco and builds its Heat Battery systems in the United States.

Rondo was founded on the premise that industrial heat — responsible for a quarter of global CO₂ emissions and a quarter of all final world energy consumption — is the hardest and most neglected decarbonization target. After 15 years working on solar industrial heat, O'Donnell concluded that the falling cost of renewable electricity had finally created the conditions for a different approach: store cheap wind and solar electricity as heat in refractory bricks, and discharge it as continuous, high-temperature industrial process heat. The Rondo Heat Battery charges using electric heaters powered by intermittent renewables, heating dense arrays of bricks to 1,100–1,500°C. Factories then draw on the stored heat as continuous high-temperature air, steam, or electricity — at costs the company states are lower than burning natural gas.

Rondo has raised over $460 million in total capital, including a $200M+ Series C in 2024. Investors include Breakthrough Energy Ventures, Prelude Ventures, Fifth Wall, Temasek, Energy Impact Partners, and SABIC. The company also received DOE and California Energy Commission support. Co-founder O'Donnell has framed the company's addressable market as 15% of global CO₂ — the fraction attributable to industrial heat — and has committed to eliminating it within 15 years.

Rondo's first commercial system deployed at Calgren Renewable Fuels in Pixley, California, followed by commercial Heat Battery installations at Heineken's Lisbon brewery — described as the largest heat battery in the global beverage industry — and at facilities across five industrial sectors including chemicals, cement, food and beverage, fuel production, and textiles. In 2024, Rondo and EDP announced a partnership to develop 2 GWh of heat battery deployments powered by 400 MW of new Portuguese wind and solar — the first energy service agreement of its kind in Europe. Rondo has deployed more than 11 commercial systems as of early 2026.