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).
That temperature can be used to generate steam and turn turbines to produce electricity, or the heat can be stored for later use outside daylight hours. It's also hot enough to be used in cheap hydrogen production – Heliogen's Bill Gross told the Abu Dhabi Sustainability Week 2021 conference in January that a 600 x 600-m (656 x 656-yd) plant could produce around a million kilograms (2.2 million lb) of green hydrogen per year at an impressively low cost around US$1.80 per kilogram (2.2 lb) – lower than the average price of dirty hydrogen today.
Rio Tinto's boron operation, rather fittingly located in Boron, California, currently uses natural gas co-generation and boilers to produce steam for its processes. The Heliogen installation will contribute up to 35,000 lb (15,876 kg) of steam per hour to the plant day and night thanks to energy storage, and Rio Tinto says this has the potential to reduce total plant emissions by about 7 percent – "equivalent to taking more than 5,000 cars off the road," says the company, neatly sidestepping the fact that it's leaving more than 70,000 cars on the road in this metaphor.
This is just a pilot, though; should it prove viable, the company will assess whether to upgrade the facility to more than three times its current production rate, and the state intention here is to pilot the technology with a view to replicating it at other Rio Tinto facilities around the world where there's enough sunlight.
This is an enormous company; Rio Tinto operates in over 35 countries with annual revenues around US$44.6 billion, and is the world's second-largest metals and mining corporation. It has committed to spending $1 billion on emissions reduction initiatives between 2020-2025, and is aiming for a 45 percent reduction in emissions by 2030, compared to what it was belching out in 2010.
So it's a banner opportunity for Heliogen to demonstrate its chops. The ability to generate both electricity and extremely high temperatures day and night makes this tech very interesting to a wide range of industries looking for sustainable ways to produce both – to the point where Gross says he can see a number of industries starting to deliberately look for hot, cloudless areas for production facilities where this kind of energy generation can prove very economical.
Check out a video below explaining the project below.
Source: Heliogen
