The plant of Almeria
In the Tabernas desert, 30 km north-east of the Andalusia town of Almeria (Spain), there is the biggest European research centre for the study of solar technologies producing electricity. That, between cactuses and rare bushes, is the best place to maximize the production of solar energy. In particular the SolAir project is being tested: it is a solar tower that uses a new system to exploit solar energy, concentrated on just one point, and transforms it into electric power. A black non-porous ceramic material is positioned on a 100 m tower on which mirrors, slightly curved and automatically oriented according to the position of the Sun, concentrate sun rays. Air is conducted inside the material pores and reaches a temperature of 700-1000°C. A ventilator produces a current that transports it and heats the water that converts into steam and turns a turbine. The plant has 3 MW power, but commercial plants that have been designed for the year 2006 have 10 MW power and use mirrors on a 90,000 square metre surface.
A heat storage system, moreover, allows to continue to produce electricity at night or when it is cloudy: the hot air is kept inside an isolated tank of porous material that, according to its dimensions, allows the plant to keep on working for several hours.
Such plants could be built everywhere in the Mediterranean and in general in all dry or semi-dry areas. Also Israel and the United States have tested this type of technologies.