Solar power might be the most up-and-coming renewable energy source, but one of the biggest drawbacks to solar power plants is their inability to generate electricity at night or during cloudy days. But now, a new venture called SolarReserve hopes to change all that using salt! Their program would save and store captured solar energy in molten salt, the new solar plant will produce up to 500 megawatts of peak power — comparable to what a regular coal power plant can produce, only with no greenhouse gas emissions.
Unlike other solar power plants, SolarReserve’s will be able to produce electricity at night or in inclement weather. You can see the commercial potential here if you note that just one megawatt is enough power roughly 1,000 U.S. households. The company hopes to build 10 plants over the next 10 to 15 years.
The concept behind new concentrated solar power plant is very similar to Seville’s solar power tower where hundreds of solar panels reflect the sun’s light to heat the water inside the tower, which later evaporates into steam that passes through series of turbines to generate electricity. However, instead of tower that holds water, SolarReserve’s holding tank will have molten salt. Huge array of mirrors will reflect light onto the tank; heated 1,000 degrees Fahrenheit liquid is then pumped into a steam generator that will turn a turbine to make electricity.
“Due to the unique ability of the product to store the energy it captures, this system will function like a conventional hydroelectric power plant, but with several advantages,” says Lee Bailey, managing director of US Renewables Group, SolarReserve parent company. “This product is more predictable than water reserves, the supply is free and inexhaustible, and the environmental impact is essentially zero.”
SolarReserve says that their use of molten salt, a mixture of sodium and potassium nitrate, instead of water or oil, allows the heat to be stored for use when sun is not present. The National Solar Thermal Test Facility conducted several studies and concluded that molten salt is the most efficient fluid when it comes to transporting sun’s heat. The study states, “molten salt is used in solar power tower systems because it is liquid at atmosphere pressure, it provides an efficient, low-cost medium in which to store thermal energy, its operating temperatures are compatible with today’s high-pressure and high-temperature steam turbines, and it is non-flammable and nontoxic.”