The new Gemasolar Power Plant near Seville in southern Spain is the world’s first solar plant to have the capacity to generate electricity even at night. More than 2600 concentrically arranged mirrors spread across 185 hectares of rural land concentrate solar energy towards a centrally located molten nitrate salt tank. As the rays converge, they super-heat the salt to over 900C, causing water around the tank to boil and drive steam turbines. In addition, any superfluous heat generated during the day is stored within the liquefied salt. It acts like a giant thermal battery for driving the turbines at night and during overcast days up to 15 hours at a time with no sunlight. But Seville, being one of the sunniest areas in Europe, this doesn’t happen very often.