Let there be light: eSolar switches on first U.S. solar thermal tower

August 6, 2009 | Camille Ricketts | Comments | |

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The U.S. solar industry just took a great leap forward with eSolar’s announcement that its 5-megawatt Sierra SunTower is now fully operational. Located in Lancaster, Calif., the array uses 24,000 mirrors to concentrate sunlight on two 160-foot towers.

The facility is technically a solar thermal plant, meaning that instead of solar cells converting sunlight directly to energy, the light is used to heat water located at the top of the towers. The steam generated turns a traditional steam turbine, which generates power for local utility Southern California Edison. The mirrors track the sun using GPS technology to keep the water heated at a consistent 800 degrees Fahrenheit, producing 800 pounds of steam per square inch.

Solar thermal has the potential to disrupt the solar industry at large, mostly because it’s cheaper to execute. After all, mirrors are much more cost-effective than silicon solar cells. eSolar’s chief executive even went as far as saying that the project represents “the lowest cost solar project in history,” and that the company could power the entire state of California with just 25 square miles of mirrors and towers.

The system devised by eSolar could be good news for consumers too, with the electricity generated costing less than the average homeowner in California usually pays.

The company has already cashed in on its technology, landing a $30 million licensing deal with the Acme Group in India, and a $10 million rights deal with NRG Energy, which has 500 megawatts worth of solar projects already in the works. It also has a partnership with utility PG&E.

Not that eSolar really needs the money — it’s already known for its generous $130 million in capital from Google.org (a tough investor to draft), the prestigious Idealab, Oak Investment Partners, Quercus Trust and NRG.

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About the Author, Camille Ricketts

Camille is the lead writer for GreenBeat. She came to VentureBeat from Google where she worked on its traditional platforms team, particularly in TV. Before that, she was a reporter for the Wall Street Journal in New York and London. Follow her on Twitter at @camillericketts, and follow VentureBeat on Twitter at @venturebeat.

With GreenBeat 2009, VentureBeat's all-star conference on all things Smart Grid, coming up in November, Camille will be expanding coverage of this exciting space. Stay up to date by following @greenbeat2009 on Twitter or by becoming a fan of the event on Facebook here.

  • Camille -- isn't the really big story that it's the only solar form that can *store* for off-peak and clouds 9molten salt and the like?), or am i wrong?
  • SunDowner
    See United States Patent #4,387,574 from 1983. Great to see this old technology being rejuvinated for the 21st century! The DOE 10 MW Solar 2 tower that was shut down in 1999 could store solar power as molten salt.
  • I hope that area never suffers hail storms.
  • AaronW
    eSolar does not use molten salt as far as I am aware. I Could be wrong but I searched and searched for indication that they do but couldn't find it. Molten salt is the real game changer for solar thermal because it allows for nighttime production. If they are not using molten salt then none of their great strategies in technology or land procurement will amount to much. They would be a force to be reckoned with but as far as I know they don't. Until they do they will only be half way there.
  • 25 Square Miles??? Really? Looks closer to around 1 square mile to me. Or is this just 1 of 25 such installations?
  • Matt McCrory
    He's saying that if you were to install 25 square miles of their solar thermal plants, enough electricity to power the entire state could be generated. You are right that this plant is nowhere close to 25 square miles :)
  • macrumpton
    One big advantage of this type of installation over a PV one is that the turbine can be powered by any appropriate source of heat, so when the sun is not shining (or shining less brightly) the steam can be generated by natural gas or some other fuel source.
  • craigermp
    This eSolar project is a beautiful example of Wholesale Distributed Generation (WDG), which is the renewables market segment that avoids the decades-long transmission build-outs because the projects are located close to loads. In addition to being able to get WDG energy online fast, WDG energy is worth at least 35% more than large transmission-interconnected energy. The AB1106 Feed-In Tariff (FIT), which is well on its way to becoming law in California this year, will unleash the WDG market segment. The FIT Coalition is leading the charge on WDG and FITs in America, and its website provides an excellent overview along with detailed analyses: www.fitcoalition.com