A US startup backed by Bill Gates is targeting solar thermal energy hitting 1,500°C that can transform carbon-heavy industrial processes and create zero-carbon fuels.

Heliogen uses advanced computer vision software to align a large array of mirrors with extreme precision in order to reflect sunlight to a single target. The California-based company claims it has already used this technology to exceed temperatures greater than 1,000 degrees Celsius, which is hot enough to replace fossil fuels in the production of steel and cement. At temperatures of 1,500°C, water and CO2 can be split to make fossil-free fuels such as hydrogen and syngas.
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Previous solar thermal systems have been designed to reach temperatures of up to only 565 degrees Celsius. While this is sufficient for generating electricity, industrial processes require much higher temperatures, and the bulk of global energy demand is detached from electricity in sectors such as transport and industrial activity.
“We’ve made great strides in deploying clean energy in our electricity system,” said Bill Gross, founder and CEO of Heliogen. “But electricity accounts for less than a quarter of global energy demand. Heliogen represents a technological leap forward in addressing the other 75 per cent of energy demand: the use of fossil fuels for industrial processes and transportation. With low-cost, ultra-high temperature process heat, we have an opportunity to make meaningful contributions to solving the climate crisis.”

Alongside Microsoft’s Gates, investors in Heliogen include venture capital firm Neotribe and Dr Patrick Soon-Shiong, a Los Angeles-based investor and entrepreneur. Neotribe’s founder and managing director, Swaroop ‘Kittu’ Kolluri, and Dr Soon-Shiong have joined Heliogen’s board of directors.
“Today, industrial processes like those used to make cement, steel, and other materials are responsible for more than a fifth of all emissions,” said Gates. “These materials are everywhere in our lives but we don’t have any proven breakthroughs that will give us affordable, zero-carbon versions of them.
“If we’re going to get to zero-carbon emissions overall, we have a lot of inventing to do. I’m pleased to have been an early backer of Bill Gross’s novel solar concentration technology. Its capacity to achieve the high temperatures required for these processes is a promising development in the quest to one day replace fossil fuel.”
And no mention of the SunriseCSP dish concentrator that achieved well over 2,000 degrees C with a 500 sqm collector over 7 years ago? Who said 565 degrees Celsius was current state of the art?
These types of thermal solar plant are great because they provide high grade, high temperature energy that may be used in many applications. However, as always, there is a downside. The Ivanpah Solar Plant in California is reckoned to kill upwards of 6,000 birds each year that fly into the concentrated energy in the beams. This is bad enough but Ivanpah is on a major bird migration route so many important species are taken out,
Or the solar power plants in Spain since early 2000s which also concentrate sun’s rays on a central point
I’m interested to see how this “single hot target” will heat a rotary kiln (1.5 x 18 m to 4 x 40 m) for cement production
There will be mechanical problems involved in changing the continuous calcination process done in heated rotary kilns to a device that creates a hot spot. It may be feasible to create a ‘hot line’ that has the length of residence for the clinker forming mixture as well as the mechanical mixing that drives off the CO2 of the lime, (CaCO3), and any other stray oxides and water s of hydration and melts the resultant CaO and the other diverse ingredients into the clinker (https://en.wikipedia.org/wiki/Clinker_(cement)) which is the final form, and which is ground to a fine anhydrous powder and sold as portland cement. There are dozens of cements, with varying other ingredients. You can make other cements from other oxidessuch as potassium. (https://www.matec-conferences.org/articles/matecconf/pdf/2017/30/matecconf_trs2017_01018.pdf)
All these drive off the CO2 via heat to make the clinker which when mied with water re-hydrates the oxide into the hydrated form by the growth of crystals of the original carbonate rock that tightly grip the added stones, called aggregate, that harden into the final concrete with the assorted mechanical properties we are used to see in sidewalks, dams etc. There are hundreds of specialty concretes. This method shows promise and with experimentation will become a major contributer to the lowering of the carbon problem – it will take decades IMHO.
Ideally a cement that does not involve the removal of CO2 by heat would be good, perhaps by the loss of water of hydration only? Would it be strong enough, cheap enough, good enough to let us live long and prosper – aye there’s the rub…