Saudi Aramco and SABIC back heat battery technology

Saudi Aramco and SABIC back heat battery technology

RIYADH, August 21, 2023 – Rondo Energy has raised USD 60 million to fund its heat battery technology from global investors including Saudi Aramco, SABIC and Microsoft, the US green energy storage entity announced on Wednesday.

The company’s other backers include Rondo Energy’s current investors Energy Ventures, Energy Impact Partners, SCG and Titan; industrial leaders including Microsoft’s Climate Innovation Fund and Rio Tinto; and climate investors SDCL Energy Efficiency Income Trust and John Doerr.

Saudi Aramco, SABIC, SCG, Titan, and SDCL Energy Efficiency Income Trust have joined the company’s strategic investor advisory board.

In 2023, Rondo Energy began operating its first commercial battery to lower the carbon intensity of biofuels produced by Calgren Renewable Fuels.


The development involved building the first commercially operating electric thermal energy storage system in the USA and the highest efficiency, highest temperature energy storage of any kind worldwide.

The company also announced that it had reached heat battery storage production capacity of 2.4 GWh per year in 2023, with plans to reach 90 GWh per year.

The technology is based on utilising accessible materials such as brick and iron wire. Bricks are heated to 1,500 Celsius and the high temperatures are accessed by blowing air flows up the brick stack, delivering either superheated air or steam to the end point at temperatures around 1,000 Celsius.

The batteries have a 50-year lifespan.

“Rondo’s technology enables intermittent sources of renewable electricity to provide heat to continuous industrial processes and has potential applications within SABIC’s decarbonisation roadmap,” said Dhaval Shah, general manager for corporate technology and innovation of SABIC.

“We see a unique opportunity for Rondo’s thermal storage solution to provide a pathway for industrial businesses to accelerate the clean energy transition,” said Brandon Middaugh, senior director of Microsoft Climate Innovation Fund.

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