A new, two mile wide, 110 megawatt solar installation is being constructed in Nevada to power the lights of Las Vegas. SolarReserve have already completed the 540 foot high central tower of the Crescent Dunes Solar Energy Project near Tonopah. They are now getting ready to add a 100 foot receiver at the top and in the summer will start erecting 10,000 billboard-sized, sun-tracking heliostat mirrors.
The tower will use a molten salt storage system to enable it to supply a constant rate of electricity, even during the night. The salt will be stored in tanks at the base of the tower at about 500°C. It will then be pumped up to the receiver section of the tower where it will pass through a series of tubes and be heated by the concentrated solar energy to temperatures around 1000°C. It will then be returned to another tank at the base of the tower for storage. When power is needed the super-heated salt can be used in a heat exchanger to produce steam and drive a traditional turbine.
SolarReserve is already working on similar projects, including larger ones in the Middle-East, and states that the main challenge they face is to bring down the cost of electricity produced by solar thermal towers. As the cost of photovoltaics has plunged some large-scale solar thermal projects have been scrapped, even though they can provide much more significant amounts of power.
The electricity is predicted to cost 13.5 cents per kilowatt-hour, cheaper than power from a new nuclear or coal plant (with carbon capture and storage), but still more expensive than a natural gas plant.
By. Charles Kennedy of Oilprice.com
Charles is a writer for Oilprice.com