Over the years, assorted startups and research groups have trumpeted the promise of solar thermal plants, which use a large array of mirrors to concentrate sunlight and produce electricity from the resulting heat. But the field has struggled to produce cheap power and gain a market foothold, even as the price of solar panels has plummeted.
Serial entrepreneur Bill Gross, however, remains a true believer in the technology. On Tuesday Gross, the chairman of the Idealab incubator and CEO of earlier solar thermal company eSolar, announced a venture that skips the electricity part and puts the heat to use directly in industrial processes.
By achieving higher temperatures than previous commercial plants, Heliogen plans to generate the heat needed to produce things like cement, steel and hydrogen. The hope is that this solar heat could replace the fossil fuels usually required to drive the necessary reactions, reducing greenhouse-gas emissions produced in the process.
If it works as hoped, it could provide a critical piece in the decarbonization puzzle. An October report from Columbia University’s Center for Global Energy Policy found that burning fossil fuels to produce heat for industrial processes produces about 10% of global carbon dioxide emissions, more than all the cars in the world.
There would, however, be limitations on where and how this could be applied. Concentrated solar plants generally only work in very sunny areas, and you can’t ship heat over long distances. So industrial companies that want to take advantage of this process may have to build new plants near these solar thermal facilities, or vice versa.
“The middle of the desert is not typically an industrial hub,” says Julio Friedmann, senior research scholar at the Center for Global Energy Policy and lead author of the report.
Heliogen, based in Pasadena, California, still needs to demonstrate that the technology will work the way it claims, and at competitive costs. The company employs about 25 people, but declines to disclose how much money it has raised.
A standard solar thermal plant achieves temperatures of a little below 600 ˚C, which is used to heat a medium like molten salt. That, in turn, is used to convert water into steam, which cranks the turbine that produces electricity.
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Helion’s trick is to use high resolution cameras and computer vision software to make tiny adjustments to each of its mirrors, aligning every solar beam onto a single, tiny point.
The company has already built a small thermal solar plant in Lancaster, which has reached temperatures above 1,000˚ C. Gross says it’s the first time such temperatures have been reached in a commercial facility, and the press release proclaims it as a “singular scientific achievement.” But observers in the field note other commercial and research groups have achieved similar temperatures at least in limited experiments and that, in any case, the trickier part is developing systems that can withstand, retain and transfer that heat.