New solar plant uses molten salt to store energy

Solar Reserve|Solar Reserve|Solar Reserve

A solar plant under construction in Australia uses molten salt to both collect and store energy for electricity generation

Australia has been in the forefront of solar technology, with construction of an entire neighbourhood powered by Tesla’s solar technology and a train that runs on solar power. Now, solar power utility company SolarReserve has received permission to begin construction on the Aurora Solar Energy Project – a AUD 650 million, 150 megawatt solar thermal plant. The plant will be built near Port Augusta, in South Australia. Once constructed, the facility will be the world’s largest single-tower solar thermal power plant.

One issue with solar power plants has been how to store the energy generated during the day for release at night. Most power plants use electricity as it is generated, because efficient storage of electricity is very difficult. The Aurora Plant solves this problem by using molten salt to store power. During the day, the plant will use more than 10,000 large tracking mirrors, called heliostats, spread over a 4-square mile area, to collect and concentrate the sun’s rays onto a large heat exchanger atop a 500-foot tower. Molten salt flows through the exchanger, absorbing the heat energy. The molten salt then flows into a thermal storage tank, where it is stored until the energy is needed. When energy is required, the molten salt is pumped into a steam generator, where it provides the heat to turn water to steam and generate electricity. The cooled salt is then pumped back up to the heat exchanger to be reheated.

Using molten salt will enable the Aurora power plant to generate 500-gigawatt hours of energy annually, enough to power the equivalent of 35 percent of all of the households in South Australia, both day and night. Australia’s Clean Energy Council executive general manager Natalie Collard told local media that, “Our electricity system is rapidly moving towards one which will be smarter and cleaner, with a range of technologies providing high-tech, reliable, lower-cost power.” The plant will also displace the equivalent of 200,000 tonnes of CO2 annually. What other solutions might there be for storing the energy generated using alternative power?