A typical large steel mill might burn through 1.5 million metric tons of coal in its furnaces in a year. It hasn’t been possible to run that type of industrial process on renewable energy, because of the extremely hot temperatures required, making nearly a quarter of global emissions hard to eliminate. But new technology—which concentrates solar thermal energy to 1,000 degrees Celsius for the first time—could transform some of the most polluting industries, including steel, cement, and petrochemical production.

The technology, which comes from a California-based startup called Heliogen, uses an array of mirrors to reflect sunlight. That’s not new, but the approach that it uses nearly doubles the amount of heat that previous solar thermal tech could produce. 

In the past, the hottest achievable temperature for this kind of solar tech was around 575 degrees Celsius. But many industrial processes—such as forming cement or steel—requires kilns with temperatures of at least 950 degrees, something that plants currently accomplish by burning dirty, cheap fuel such as coal, peat, or even tires and trash. Now, through the use of mirrors that act as an enormous magnifying glass, reaching the sky-high temperatures needed for steel production is now possible.

To make their technology available for all industrial producers, Heliogen is offering generous deals. If companies buy the equipment outright, the payback period will be around two to three years. Companies can also choose to have Heliogen install and run the equipment and just pay for the energy provided, at a lower cost than they were paying for fossil fuels. 

Heliogen believes companies want to change, and they want to be there to help them make that greener change. With a mindset like this, it’s no wonder Bill Gates is helping fund the startup.