Gates-Backed Solar Focusing Company Could Make High-Temperature Manufacturing Clean

The Heliogen test facility at Lancaster California. The mirrors are focused on the tower, raising temperatures to those that approach kilns used for cement or glass production. Heliogen

A company has exited stealth mode to announce the successful production of temperatures above 1,000ºC (1,832ºF) using the careful focusing of sunlight. The heat is sufficient to potentially displace fossil fuels in the manufacturing of energy-intense products like cement and steel. The company's prominent backers think it will beat existing methods not only for the health of the planet, but on cost too.

In most production of energy, heat is a waste product, a measure of inefficiency. However, a lot of manufacturing requires immensely high temperatures, currently achieved with fossil fuels. Ideas for environmentally friendly ways to replace these have usually centered on using solar or wind energy to produce clean fuels, but Bill Gross, founder of technology innovator Idealab decided to cut out the middle step and use the sunlight directly. After all, every child with a magnifying glass has learned the focused Sun can get dangerously hot.

Naturally Gross is not the first to think of the idea; Archimedes is said to have used it to defend Syracuse 200 years before Jesus and the potential potency of reflected sunlight featured in science fiction 60 years ago.

The problem has been that to achieve the extraordinary temperatures required in cement or glass manufacturing, the focus cannot waiver even slightly as the Sun moves through the sky. Every mirror shining a few degrees off target lowers the temperatures produced. Not a problem if you want to boil water, and tolerable for heating molten salt, but a major obstacle to building an industrial oven.

Gross surrounded the target site with cameras just far enough away not to get scorched. Rather than track sunlight, the cameras receive the reflection of the Sun's halo, indicating the sunlight is focused on the correct spot. The slightest misalignment of a 1.5-square-meter (15-square-foot) mirror leads to feedback for adjustment. At 30 frames per second and thousands of mirrors, the data processing as the Sun moves across the sky is immense, but that's much less of an obstacle than it once was.

The company Gross founded to develop the idea, Heliogen, won backing from Bill Gates and Los Angeles Times owner Professor Patrick Soon-Shiong while keeping its work quiet from the rest of the world until it had something to show for its work.

This week Gross announced a demonstration plant in the California desert had achieved the 1,000ºC (1,832ºF) threshold, almost double that used for concentrating solar electricity generation. Heliogen has ambitions to achieve 1,500ºC (2,732ºF), more than a quarter of the temperature of the Sun's surface, which would make possible the splitting of water to produce hydrogen without electricity.

Even if fossil fuels are required to maintain operations after dark, as is anticipated initially, the technology could give a competitive advantage to hotter, drier parts of the world when it comes to energy-intensive manufacturing.

“Today, industrial processes like those used to make cement, steel, and other materials are responsible for more than a fifth of all emissions,” Gates said in a statement

In addition to making industrial production clean, Heliogen's technology could breathe new life into the solar thermal for electricity plants. One of the reasons these have been outpaced by photovoltaic panels, despite their capacity to keep producing after dusk, is that it takes months of careful adjustment with little to no power produced before operations can start. Gross thinks he can offer better focus almost immediately.

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