The Andasol 1 solar thermal power plant in Andalucía, Spain, is to soon commence charging the installation built expressly for storing renewable energy.

Located on the Guadix plateau in the Spanish province of Granada, Andasol 1 is to go into operation as Europe's first parabolic trough power plant.

A report, filed by spectrum.ieee.org, highlighted that heat from the solar thermal power station's 510 000-square-meter field of solar collectors will be stored in 28500 tons of molten salt—enough to run the plant's 50-megawatt steam turbine for up to 7.5 hours after dark. The developers say Andasol 1's electricity will cost 11 percent less to produce than a similar plant without energy storage—dropping from 303 euros per megawatt-hour to 271 euros per MWh.

The Andasol 1 and 2 plants are currently under construction in southern Spain. With a gross electricity output of around 180 GWh per year and a collector surface area of over 510, 000 square meters - equal to 70 soccer pitches - they are the largest solar power plants in the world. As a Solar Millennium partner, the ACS/Cobra Group has a 75 percent share in each of the Andasol 1 and Andasol 2 projects.

The lower cost of production is actually a by-product of Andasol 1's energy-storage system, according to Solar Millennium's engineering subsidiary Flagsol's Paul Nava. He says storage is a means of maximising the net energy production from each plant and "thus maximises the revenues paid under Spain's generous incentive programme for renewable-energy generation."

The report added that a feed-in tariff for solar thermal power pays 2.5 to 3 times the average power price for every MWh of energy generated for 25 years (though new rules will reduce the rate for future projects) but limits the capacity of qualifying facilities to 50 MW. Storage enables Andasol 1 to run its 50-MW turbine for more hours. Nava estimates that Andasol 1 will generate 178 000 MWh of renewable electricity per year, whereas the same field of solar collectors and turbine would turn out just 117 000 MWh sans storage—a difference worth more than 24 million euros per year (US $36 million) at today's power prices.