It uses the same melted salt for the life of the power plant and receives a lifetime of energy from our greatest source of power—The Sun!
By Linn Smith
July 16, 2014— Can solar energy be stored? Yes! The first use of solar thermal energy equipment technology, that was recorded, was developed in the Sahara Desert in about 1910, where a steam engine was powered using a mirror system for sunlight. The sunlight heated water, turning it into steam. But during WWI further development was abandoned because oil was abundant, and easily obtained.
Today, Solar Thermal Energy (STE) is being harnessed for the world’s largest solar plant which uses molten salt for storage—the Crescent Dunes Solar Plant in Nevada.
The Cycle of Solar Thermal Energy
Here’s how it works: A series of mirrors (heliostats) track the sun on two axes, concentrating the solar radiation on a receiver in the upper part of the tower where the heat is transferred to the molten salts. Molten salt is a perfect heat capture source, as it maintains its liquid state even above 1,000 degrees Fahrenheit. The sunlight heats up the salts and puts the molten salts in proximity to water via a heat exchanger–creating steam. The hot steam can then be made to turn turbines without losing much of the original absorbed solar energy. The salt is then piped back into another storage tank, where it is cooled and reheated later for the same process. Water is also recycled, as it travels back to a water holding tank where it will stay until needed again.
This process uses the stored solar to generate reliable, uninterrupted electricity to homes during the night or on cloudy days when direct solar power isn’t available or during peak demand hours when extra power is necessary. There is zero emissions or waste with the use of Solar Thermal Energy. It uses the same melted salt for the life of the plant and receives a lifetime of energy from our greatest power source—The Sun!
Crescent Dunes Solar Plant is projected to be fully operational by the end of 2014, providing power to up to 75,000 homes. According to SolarReserve, the developer of Crescent Dunes and other large-scale solar energy projects, their goal is to, “Reduce the nation’s reliance on fossil energy supplies, producing enough solar energy in one year equivalent to about one-eighth of the total output of Hoover Dam. The project uses a hybrid cooling power system so that water use is at a strict minimum in this important desert ecosystem.”
Solar energy avoids greenhouse gas emissions produced by a fossil-fueled power plant.