Thermal storage improvements make solar energy more viable

Science : For solar power to be a viable alternative energy option, companies need to be able to store some solar energy to use when the Sun is not shining. Spain’s Andasol complex, one of the world’s largest solar power stations, has been so successful in doing just that that it has been classified as a “predictable” source of energy, writes Edwin Cartlidge for Science. Andasol produces electricity in two stages: The Sun heats a synthetic oil, some of which is used to generate steam that turns a turbine and some of which is used to heat up molten salt that stores the energy for later use. Now some companies are working to improve on that design. Instead of using one material to absorb the Sun’s heat and a second material to store it, they use one material to do both. Such a direct storage method would eliminate one of the two heat exchangers and make the electricity production more efficient. Although the current global capacity of solar thermal power plants is minuscule at just over 1 gigawatt, more solar technology projects are currently in development or under construction in the US, Spain, North Africa, China, India, and elsewhere that could increase that capacity to about 15 gigawatts.