Gemasolar is the first commercial-scale plant in the world to apply central tower receiver and molten salt heat storage technology. This unique thermosolar power station stands out in Fuentes de Andalucia, in southern Spain, and it’s up and running since last May 2011.
From the road between Seville and Cordoba, one can see its central tower lit up like a beacon by 2,600 solar mirrors, each 120 square metres (28,500 square feet), that surround it in an immense 195-hectare circle. The relevance of this plant, which investment cost exceeds 200 million euros, lies in its technological uniqueness, since it opens up the way for new thermosolar electrical generation technology. With 2,650 heliostats on 185 hectares and a heat storage system which permits electrical generation for up to 15 hours without any solar feed, Gemasolar power station is expected to produce around 110 GWh per year.
Santago Arias, is the technical director of Torresol Energy, and is nowadays running the station. “It is the first station in the world that works 24 hours a day, a solar power station that works day and night!” he says. The mechanism is next: the solar panels reflect the suns rays on to the tower, transmitting energy at an intensity of 1,000 times higher than that of the sun’s rays reaching the earth. Energy is stored in a vat filled with molten salts at a temperature of more than 500 degrees C (930 F) that are used to produce steam to turn the turbines and create electricity. Gemasolar’s capacity to store energy allows the plant to transmit power during the night, relying on energy it has accumulated during the day, producing 60% more energy than a station without storage capacity. “The amount of energy we produce a year is equal to the consumption of 30,000 Spanish households,” Arias said, an annual saving of 30,000 tons of CO2.
“We have three projects ready but stalled” because of the aid suspension, Arias said, admitting that in a difficult global economy the group has not managed to sell the Gemasolar techology abroad despite huge interest outside Spain.