Anyone who has tried to use the glut of solar powered yard decorations that dot the aisles of lawn and garden stores knows you’re lucky if they glow past 9 pm and manage to last for an entire summer. Sure, there are a few homes and offices around our communities with large rooftop solar panels, but most of us are still waiting for that next generation of better, cheaper technology that will truly replace our electric company.
Now, imagine how far off the practicality of solar energy must seem for heavy industry—the kinds of companies that need smokestacks to manufacture their products. Incredible as it sounds, in late 2019 a solar energy company called Heliogen announced that their technology was able to concentrate solar energy to produce temperatures in excess of 1,000 degrees Celsius (more than 1,800⁰ F).1 As a point of reference, the temperature at the center of the big sunspots thrown off by our Sun can be as low as 4,000⁰ C (7,300⁰ F).2
That 1,000⁰ C benchmark is critical. As the company states, “At that temperature, Heliogen can replace the use of fossil fuels in critical industrial processes, including the production of cement, steel, and petrochemicals, dramatically reducing greenhouse gas emissions from these activities.” 1
According to many press reports,3, 4, 5 Heliogen had been operating in secret with Bill Gates as its major backer. The company’s founder told CNN Business, “We are rolling out technology that can beat the price of fossil fuels and also not make the CO2 emissions…And that’s really the holy grail.”3
According to Heliogen, their quiet backer Bill Gates had this to say, “Today, industrial processes like those used to make cement, steel, and other materials are responsible for more than a fifth of all emissions…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.”1
In contrast to those rooftop panels we are used to seeing on buildings, concentrated solar uses mirrors to reflect sunlight to a single point. A writer for Popular Mechanics likens the technology to “using a magnifying glass to start a fire. Only much bigger.” In this case, the magnifying glass has the help of “computer vision software to hyper-accurately align a large array of mirrors to reflect sunlight to a single target.”1 The photo below shows a receiver mounted on a tower that captures the sunlight from 1,000 mirrors, the “equivalent to 1,200+ suns,”4 that is converted to ultra-high temperature heat.
A writer for Wired explained that the Heliogen system’s machine vision is used “to constantly tweak the positions of the mirrors so they are always pointed at the most optimal spot. That allows it to achieve roughly the same temperatures with much less energy, ultimately dumping around 300 kilowatts into an area only a little larger than a basketball hoop.”5 Wired quotes the company CEO, Bill Gross, as saying, “We have a black, silicon carbide plate that the light is shining on and it is glowing white-hot from all that energy. It’s insane.” 5
Concentrated solar energy is not new. “Previous commercial concentrating solar thermal systems have been designed to reach temperatures of up to only 565 degrees Celsius – useful for power generation, but insufficient for many industrial processes. Many of these processes require much higher temperatures, which have traditionally been reached through the burning of fossil fuels.”1
CNN reports that “Heliogen’s biggest challenge will be convincing industrial companies using fossil fuels to make the investment required to switch over. Gross said the company has been talking to potential customers privately and plans to soon announce its first customers.” 3
Images courtesy of Heliogen
References
1Heliogen. Press Release. Heliogen Achieves Breakthrough Temperatures from Concentrated Sunlight for Industrial Processes. 19 November 2019. https://heliogen.com/press-release-heliogen-achieves-breakthrough-temperatures-from-concentrated-sunlight-for-industrial-processes-with-momentum-toward-commercial-hydrogen-fuel-creation/
2Sharp T. How Hot Is the Sun? Space.com. 19 October 2017. https://www.space.com/17137-how-hot-is-the-sun.html
3Egan M. Secretive energy startup backed by Bill Gates achieves solar breakthrough. CNN. 19 November 2019. https://www.cnn.com/2019/11/19/business/heliogen-solar-energy-bill-gates/index.html
4Delbert C. Bill Gate’s Secret Solar Startup Has Generated Extreme Heat with Mirrors. Popular Mechanics. 19 November 2019. https://www.popularmechanics.com/science/green-tech/a29847655/heliogen-solar-heat-mirrors/
5Oberhaus D. A Solar ‘Breakthrough’ Won’t Solve Cement’s Carbon Problem. Wired. 22 November 2019. https://www.wired.com/story/a-solar-breakthrough-wont-solve-cements-carbon-problem/
Video: Heliogen, An Energy Startup Backed by Bill Gates Claims Solar Breakthrough. CNN. 27 November 2019. https://youtu.be/2D7ylv_gaJ4
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