To make people embrace solar and give up fossil fuels means solar has to be cheap. How cheap? According to the U.S. Department of Energy, 6 cents per kilowatt-hour cheap. This is how the Halotechnics company, a solar-thermal startup and ARPA-E recipient, came to be.
News usually focus on the progress PV solar cells register, making prices drop. However, we hear less about solar thermal power, even though it’s more reliable. Think about how much longer they keep the solar heat on molten salt solutions, powering steam turbines and generating electricity in the middle of the night, if needed.
So Halotechnics approached things in a new way: it tried out nearly 18,000 mixtures of salts and forms of molten glass materials, using a high-throughput technique, until it found the right material for the temperature increase.
Regular window glass melts at around 600 °C, but this screening chemical process revealed a glass that does so at 400 °C and performs very well even at 1,200 °C. MIT reports that, if the melted glass helps power a gas turbine and the rest of the heat a steam one, the efficiency will reach 52%.
Thanks to them, the people in the industry can use many more degrees to store the heat in power plants. The longer they’ll be able to keep the temperatures high, the longer the generators will run and the less it will cost, making the electricity price lower.
However, engineering hurdles won’t be slow, like how to find the proper materials to enclose extremely hot molten glass. Until that happens, commercialization of the technology will have to wait.
As Mark Mehos, manager of the National Renewable Energy Laboratory’s Concentrated Solar Power program, in Golden, Colorado says: “The systems that are commercial today are limited to about 565 °C—that’s the molten salt tower plants. The tower and optics themselves can hit higher temperatures, but you’re limited by the salt temperature right now.” Better to remain optimistic – just as they found the material mix-ups, they’ll be sure to find the containing ones!