Solar-thermal power plants concentrate the sun’s energy using huge arrays of mirrors. AI is helping those arrays stay in focus.

What happened: Heliogen, a solar-thermal startup, developed a computer vision setup that tracks hundreds of mirrors at once. The system detects reflectors that go off kilter and adjusts them to concentrate sunlight. The system recently heated a boiler to 1,000 degrees Celsius, a temperature that allows for industrial processes. Serial entrepreneur and Heliogen founder Bill T. Gross delivers his pitch in this video.

How it works: A solar-thermal plant's central feature is a tower topped by a boiler. Hundreds, sometimes thousands, of mirrors encircle the tower. By focusing heat on the boiler, they produce steam, which spins a turbine, generating electricity. However, factors like wind, ground subsidence, and natural warping can cause mirrors to drift out of focus, reducing the plant’s efficiency. Heliogen's system calibrates them automatically.

  • Heliogen’s tower contains a plate designed to conduct heat for use in industrial processes like smelting steel and making concrete.
  • Four cameras around the plate monitor the corners of each mirror. If light reflected by a corner is brighter than the center, the system sends a message to servo controllers to adjust the mirror accordingly.

Why it matters: 1,000 degrees Celsius is a milestone; most solar-thermal plants reach half that temperature. But the company’s goal is 1,500 degrees. At this temperature, it’s possible to split atmospheric carbon dioxide and water into their constituent molecules of hydrogen and carbon. Heliogen aims to start by producing hydrogen to generate power via fuel cells. Ultimately, it aims to recombine hydrogen and carbon into hydrocarbon fuels — no fossils required.

Yes, but: A two-part critique published by the news website CleanTechnica points out that Heliogen’s technology produces a hot spot high above ground, where the heat isn’t immediately useful and is difficult to transport. Moreover, industrial facilities would need to be very nearby, potentially casting shadows over the mirrors. “I think it’s more likely that [Heliogen's] core machine learning innovation regarding halo focusing will find a completely different niche outside of concentrated solar,” the author concludes.

We’re thinking: Heliogen has intriguing technology, a seasoned leader, and a high-profile backer in Bill Gates. It's exciting to see AI helping to make cheaper, cleaner alternatives to highly polluting industrial processes.

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