The alternative energy space has been heating up this past decade. With money pouring in from both the private and public sector, the industry is poised to get even hotter. But few businesses in the space can bring the heat like Heliogen, a Southern California concentrated solar power company.
Concentrated solar power (CSP) is generated by coordinating a series of mirrors or lenses to reflect a large area of sunlight at a small receiver — usually located on a tower in the center of a field. Most of these CSP facilities look like an eco-friendly version of Peter Jackson’s depiction of the Tower of Isengard.
The concentrated light gathered at the receiver on the tower then produces the heat that becomes thermal energy, which can be stored in a rock bed and used day and night.
“Heliogen builds an enormous magnifying glass,” says Bill Gross, serial entrepreneur and founder of Heliogen. “We concentrate sunlight to such high temperatures and we can use that to avoid the burning of fossil fuels.”
Using a field of small ordinary glass mirrors (called heliostats) and extraordinary computer vision powered by artificial intelligence, Heliogen has managed to generate thermal energy at steel-melting temperatures north of 1,500 degrees Celsius (one third of the surface of the sun).
Heliogen’s ability to generate and store heat at such high temperatures makes their product especially useful for the industrial world. High carbon footprint processes like cement making, steel making, and glass making all use heat rather than electricity. Heliogen is trying to help these industries by providing an environmentally friendly product that also costs less than burning fossil fuels to create heat.
“My dream has always been to power the planet renewably,” says Gross. “The impact that Heliogen can have is to show the world that it’s actually possible. Companies can save money, and go to zero-emissions, and have energy security at the same time.”
Concentrated solar power generation differs greatly in both method and product from the more well-known photovoltaic power generation (these are the panels you see on the top of houses). Those photovoltaic panels are made with silicon to create electricity that is stored in batteries made of lithium and cobalt. Heliogen uses small mirrors made of abundantly available glass to concentrate the thermal energy, and ordinary rocks to store it.
But concentrated solar power isn’t a new concept. The first version of a concentrated solar plant was built by Professor Giovanni Francia in Genoa, Italy during the late 1960s. That plant was able to reach temperatures of up to 500 degrees Celsius. Heliogen plants have the advantage of artificially intelligent computer vision that is in constant communication with the heliostats. Those heliostats will be angled towards or away from the receiver to achieve whatever heat meets the customer’s needs.
Because that heat is stored in what looks like a giant thermos full of rocks, a Heliogen refinery is able to provide a steady flow of 5 megawatt hours of energy both day and night. That’s enough energy to power more than 3,000 U.S. homes.
Heliogen can do a few different things with the heat they are producing. They can feed that heat directly into heavy industrial processes that need those thousand degree temperatures to operate, they can run a CO2 turbine to power industrial facilities, and they can split water to create green hydrogen fuel that can be used for everything from transportation to household heating.
With the world experimenting more and more with alternative energy, the future may be a bright one for Heliogen. “Where do we see ourselves in ten years?” Gross muses. “Plants like this all over the world. In every sunny region these should be built. We want to build these in Australia, Chile, South Africa and North Africa…A thousand Heliogen solar refineries on each of three continents. If we can build that over the next few decades, that would avoid 5%, over their lifetime, of all the CO2 emissions of planet Earth.”