She seduced Bill Gates, and promises to revolutionize the fight against global warming. The richest man in the world has invested in the solar energy company Heliogen, which has developed a technology that can significantly reduce greenhouse gas emissions.
Heliogen unveiled, on Tuesday, November 19, its prototype of a small solar power station capable of converting solar radiation into a source of heat at more than 1,000 ° C. The start-up has set up around Lancaster, Pennsylvania, its first site, a field of mirrors turned to the sun and responsible for transforming its rays into energy. It would be, according to Heliogen, the first commercially viable solution for producing materials such as cement, steel or glass without emitting any CO2.
The sun rather than fossil fuels
The announcement is great for those who rely on solar energy to limit greenhouse gas emissions. "Today, conventional processes used by the industry to obtain the chemical reaction necessary for the manufacture of cement, for example, involve the combustion of fossil fuel, such as tires or waste," admits Stéphane Abanades, researcher at the laboratory. Promes (Processes, materials and solar energy) of the CNRS, contacted by France 24. Substituting these highly polluting fuels with clean energy sources such as the sun would be a great leap forward in the fight against greenhouse gas emissions. . According to the International Energy Agency, cement alone accounts for 7% of global CO2 emissions.
But to reach the chemical reaction, you need intense heat. "The manufacture of cement requires, first of all, to heat the particles to over 900 ° C, then a second time at 1400 ° C," says the French scientist. "Until now, the proposed commercial solar solutions only allowed us to reach temperatures of 565 ° C, which is not enough for industrial applications," says Heliogen.
The start-up claims to have managed to push the thermometer up to more than 1,000 ° C by boosting its prototype plant to artificial intelligence (AI). Algorithms are used to precisely direct the tens, or hundreds of mirrors to a single point of the sun. "This use of AI seems to be the main innovation presented by this company, because it is important to be able to turn the mirrors exactly towards the same point in order to maximize the reflection and the concentration of heat," emphasizes Stéphane Abanades.
Not so new
For this expert, AI aside, "it's a lot of communication". Thus, scientists have long been successful in creating solar ovens where the temperature exceeds 1000 ° C. "We've been working on it for 40 years, and in France, there are some that can reach a temperature of 3,000 ° C," he says.
But there is a difference between these lab devices and what Heliogen offers. The solar ovens referred to by Stéphane Abanades consist of "two layers: one with mirrors and the other containing a concentrator to multiply by ten the heat released by the rays". It is therefore a more bulky device, and more expensive than the mini-central American start-up, which in turn uses only the mirrors to generate heat.
The Heliogen solution seems more likely to interest manufacturers who are always quick to look at the expense before switching to a new technology. "For now, the main obstacle to the adoption of solar chemistry to manufacture these materials is its higher cost than the use of fossil fuels", confirms Stéphane Abanades.
Still, the system developed by the start-up funded by Bill Gates must be able to be deployed on an industrial scale. Stéphane Abanades has doubts about this because he misses important information in the very triumphalist speech of Heliogen. Thus, there is no reference anywhere in the press release, on the company's website or in the answers given to the press about the thermal power of this small plant. "This is essential, because it allows you to estimate the amount of energy that can be produced. For an industrial application, it would be necessary that the power station turns to a power included, at least, between 10 and 100 megawatts ", explains the French researcher.
A fuzzy cost
The Lancaster site is also far from large enough to begin meeting the energy needs of industrial manufacturers of cement, steel and other materials. The start-up "is obviously using small mirrors. It's going to take a lot more and as each has to be ordered separately, operating costs can go up, "says Stéphane Abanades.
Finally, beware of the misleading appearances of Silicon Valley. The technology unveiled by Heliogen looks promising, and enthusiastic investors like Bill Gates. But it was also the case for other start-ups like Theranos, which promised to revolutionize the e-health sector but was actually based on wind, or WeWork, the coworking giant who just canceled his IPO after revelations about the state of its finances. The fight against global warming deserves better than being the scene of a new technological scandal.