Power at Night thanks to Mirrors
While it’s nice to be able to take a hot shower after sunset, we wonder if it is also possible to store solar energy to generate electricity. The answer is yes! It is achieved by using bundling solar beams to generate extreme heat. The technology is called Concentrated Solar Power (CSP). Various solar-power plants using CSP can be found in Andalusia. We drive around the countryside in search for these big installations. Half an hour’s drive from Seville we see thousands of shiny mirrors, set in endless rows. And a little further down mirrors surround a high tower. It is a futuristic sight in the wide and barren landscape.
Chain Reaction: From Light to Electricity
So how does it work? We visit a CSP plant in Palma del Rio, between Seville and Córdoba to find out. Engineer Andrés Lastra explains it to us while leading us along large, curved mirrors. Andrés points at an arm-thick pipe which runs in front of the mirrors. “Synthetic oil flows through the pipes. The mirrors reflect the sunlight and concentrate it on these pipes, which heats the oil to almost 400 degrees Celsius. The hot oil turns water into steam, which drives turbines to generate electricity.”
And what about storage? “The hot oil can be stored in tanks so that electricity production can continue even at night.” The storage of energy is thus built into the design of these plants. A similar technique is used in the high-tower CSP plant which we saw along the road. There, the sunbeams heat a salt solution in the tower. The salt slowly releases the heat to turn water into steam.