Clean Power PS10 Solar Thermal Power Tower. Courtesy of affloresm from WIki Commons.

Published on July 4th, 2011 | by Nicholas Brown


World’s First Solar Power Plant that Works at Night Constructed

July 4th, 2011 by  

PS10 Solar Thermal Power Tower. Courtesy of affloresm from WIki Commons.

Gemasolar has completed the construction of the world’s first solar power plant capable of generating electricity all day and night. As significant as the “all night” feature sounds, keep in mind that the fact that solar power plants do not normally generate electricity at night is not actually their biggest reliability obstacle — the electricity generation interruption from clouds is more problematic (see more on that below). Luckily, this power plant design tackles both issues.

This plant is able to produce electricity all day and night due to the fact that it has 15 hours of energy storage to back it up, when cloudy and at night too.

The fact that weather varies unpredictably during the day, causing power production to fluctuate is much more important than the lack of sunlight during the night, because power plant operators know exactly when night time starts, so any other power plant can be scheduled to start for night time operation.

Conventional coal, nuclear and steam natural gas power plants cannot be started quickly enough to compensate for cloudy weather. Therefore, solar power plants need to be backed up by peaking generators or energy storage.

This power plant is sometimes described as one which stores energy in a salt “battery” — it is not actually a battery, though. This type of power plant concentrates intensely hot sunlight onto what is called a collector, which then eventually transfers heat to molten salt where it is stored for later use.

Heat from the molten salt is used to help boil water when it is cloudy, and exclusively at night due to the absence of sunlight. Simply put: this is the storage of heat to boil water later if there is not enough solar energy to boil the water vigorously enough at that time.

This is called thermal energy storage. The salt being used is actually 60% potassium nitrate and 40% sodium nitrate and loses 1% of the heat being stored per day.

This is a 19.9 MW plant that is expected to produce 110,000 MWh or 110 GWh per year. The world’s first “baseload” solar power plant has been constructed in the Spanish province of Andalucia, Torresol.

h/t Forbes 
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About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is:

  • Kalbolaryo

    Maybe the next solar panel will be like a solar battery. Produce elecrticity when shine upon because substances embedded in it change into another substances and back when shine is out.

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  • If they doubled the generating capacity in order to sell more power during the evening, they would most likely need to rework the entire surrounding power grid in order to handle the extra flow of electricity.

  • If they doubled the generating capacity in order to sell more power during the evening, they would most likely need to rework the entire surrounding power grid in order to handle the extra flow of electricity.

  • From this article I do not understand what innovation in electricity production Gemasolar has created, the innovation is in the new battery?

  • No More Naked Roofs

    When Charlie Sheen was asked about his views on the ability to store solar energy through molten salt technology, he gave a one word response, “WINNING”

  • Barrysedwood

    Aren’t ALL CSP plants capable of salt storage?

  • The progress of solar energy is very encouraging and this storage solution is great. Is there anything planned like this for the US in the near future?

  • sola

    The 1%/day self-discharge ratio is great for such a big storage facility.

  • tibi stibi

    any info about cost per watt??
    is this done by the market or was there govermental finance needed?

    • Anonymous

      i’m pretty positive there was govt financing from what i read many months back, but not 100% sure of that. haven’t seen a price tag (or cost per watt). if you find it, feel free to share it here & we’ll add it in!

  • Nicholas

    Thank you, i’m sorry about that unit error. A link to more information is at the bottom.

  • the wrong units at the end, should probably be MWh and GWh? Also, it would be nice to get a link to more information, and at least know where this project has been built, and when it started operating. I’m guessing it’s in Spain?

    • Anonymous

      Thanks for the catch on the units. The location (yes, Spain) was in the original post — last line. As Nicholas notes, link with more info added.

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