Solar energy – even without the sun!
Posted on October, 21st 2016.
The Crescent Dunes solar power plant in Nevada provides energy - day and night!
In Nevada (US), 75,000 homes can be powered by solar energy – energy that has zero emissions, is renewable, inexhaustible and accessible day and night, whatever the weather. The electricity comes from Tonopah, in the desert 300 kilometers from Las Vegas.
Unlike photovoltaic technology which converts solar energy into electricity from panels, this installation uses molten salt to store energy. It can therefore be restored anytime, even after the sun has set.
10,347 mirrors and a 195 meter tower
The technology used is based on thermodynamics. 10,347 pivoting mirrors the size of a display panel move like sunflowers. These heliostats reflect solar energy to a tower 195 meters tall containing salt. The solar energy heats the salt to as much as 565 °C. Molten and then the equivalent of a thermal battery, it is circulated through a heat exchanger which generates steam at very high temperature. This steam drives a turbine that generates electricity.
Elsewhere in the world, there are other so–called concentrating plants, which use sunlight to heat water and turn it into steam. The disadvantage is that the water evaporates more readily than salt, is more difficult to store, and is a resource that needs to be protected. Especially in the desert.
The end of nuclear or fossil fuel backup
Crescent Dunes has another advantage. By storing up to 10 hours of energy, the plant eliminates the need for nuclear or fossil fuel power plants to back up shortages of electricity on cloudy days or during intensive use during the evening hours.
Producing 110 MWh, Crescent Dunes is for the time being the largest thermodynamic solar power plant using molten salt. Until that is SolarReserve’s next project in southern Australia which will be capable of generating 880 MWh of solar electricity.
Main picture: Getty Images