Intelligent Energy

Solar plant generates power day and night

Solar plant generates power day and night

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Gemasolar, the concentrated solar power plant in Spain designed to supply power 24/7 -- yes, even at night -- was officially inaugurated last week. Check out photos of this novel technology that might eventually come to the United States.

Gemasolar, the concentrated solar power plant in Spain designed to supply power 24/7 -- yes, even at night -- was officially inaugurated last week.

Technically, the plant supplied its first 24 hours of uninterrupted power may back in July. But the inauguration was the perfect excuse to write about the novel technology and provide a few photos of the massive project developed by Torresol Energy, a joint venture between Abu Dhabi's Masdar and Spanish engineering firm Sener.

Plus, it's quite possible a project similar to Gemasolar will come to the United States. Torresol Energy is scheduled to participate in the Solar Power International 2011 to be held Oct. 17 to Oct. 20 in Dallas. The company says it will introduce future projects to the American market at the event.

Gemasolar solves a major problem with solar-generated power: It's variability. When the sun sets, the renewable power sources drop off and that can create headaches for grid operators trying to maintain a steady electricity supply. Gemasolar uses thousands of mirrors to concentrate the sun's heat onto a receiver atop a 450-foot central tower.

The reflected sunlight is directed onto molten salt, not oil like in other concentrated solar power plants. The heat collected by the salts generates high pressure steam that drives a turbine to generate electricity. The surplus heat accumulated during sun hours is stored in a molten-salt tank, where it can be used to produce electricity at night or during cloudy days.

A few Gemasolar figures:

  • There are 2,650 heliostats on 457 acres;
  • The plant can reach operating temperatures of over 932 degree Fahrenheit (500 degrees Celsius)
  • 19.9 megawatt capacity can supply power to 27,500 households in south of Spain
  • The annual production of Gemasolar is the equivalent of the energy generated in a conventional thermal plant burning 89,000 tons of lignite or the converted energy of 217,000 oil barrels.
  • The plant is expected to save more than 30,000 tons of carbon dioxide emissions a year.

The photo below shows construction on the Gemasolar plant. The molten-salt storage tank has enough capacity to allow the plant to stretch its electrical production 15 hours beyond sunset, regardless of the cloud cover.

Photo: Torresol Energy

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Kirsten Korosec

Contributing Editor

Kirsten Korosec has written for Technology Review, Marketing News, The Hill, BNET and Bloomberg News. She holds a degree from Northwestern University's Medill School of Journalism. She is based in Tucson, Arizona. Follow her on Twitter. Disclosure