Mining giant Rio Tinto has announced it's going to install a pilot version of Heliogen's high-temperature "solar refinery" at a Californian boron mine, supplying clean energy as well as heat for industrial processes, with operations expected to start in 2022.

Heliogen's technology is an AI-enhanced version of a concentrating solar thermal generator; a huge array of mirrors surrounding a tall tower, each of which tracks the Sun's position in the sky and tilts itself to perfectly reflect the sunlight onto a collector in the top of the tower.

With a large number of these mirrors – potentially thousands, capturing sunlight across a large spread of land and focusing it all on one spot – the collector gets extremely hot. In 2019, Heliogen's demo plant in Lancaster, California, recorded temperatures exceeding 1,000 °C (1,832 °F), using a relatively small field of AI-guided mirrors, and the company is now talking about temperatures over 1,800 °C (3,272 °F).