Does Power Tower Solar Harm Birds And Bats?

In a remarkable document, the head of the U.S. Fish and Wildlife Service’s division office in Palm Springs, Calif., is asking that regulators put off approval of proposed power tower solar projects in order to get data on the impact they could have on birds and bats.

The request to the California Energy Commission and other regulators – first reported by Chris Clarke on the ReWire blog – comes as BrightSource Energy, which is more than halfway done with the Ivanpah plant in the Mojave Desert, is pursuing permits to build the Rio Mesa and Hidden Hills power tower projects in the Southern California desert. This type of concentrating solar power technology uses heliostats — large mirrors — to direct light onto a receiving tower, where water or other fluids can be heated and then used to produce energy.

ivanpah birds power tower

The three-tower Ivanpah project, under construction (image via BrightSource Energy)

“It would be beneficial to the permitting process for pending and future projects, including Hidden Hills and Rio Mesa, to gather monitoring data that answer some of the questions about avian physiological tolerance and behavioral response to power towers, from already approved projects, before approving more projects,” wrote Pete Sorensen, division chief of the Palm Springs Fish and Wildlife office, in a letter to the state energy commission.

Sorensen went on to call for “a couple of years of scientifically robust monitoring,” a move that would seemingly delay any new approvals for several years, were it embraced.

When we originally posted this story, we included a link to Sorensen’s letter, which had been posted to the California Energy Commission website. But apparently the letter and its implications raised a ruckus over at Fish and Wildlife. The letter has been removed from the energy commission’s website. And, as noted in a comment posted to this story from BrightSource Energy (see below), Fish and Wildlife contacted ReWire to say the disappeared Sorensen letter “merely urges … fellow agencies to proceed with caution in approving such projects until more research is done.”

In any case, according to the National Renewable Energy Laboratory, there is currently only one power tower plant operating in the United States: the Sierra SunTower (previously known as the Gaskell Sun Tower) in Lancaster, Calif. At 5 megawatts and with 24,000 heliostats, it’s tiny compared to Ivanpah, rated at 392 MW using 173,000 of the giant mirrors to reflect light onto three towers. Ivanpah is expected to be completed in 2013, as is SolarReserve’s 110-MW Crescent Dunes Solar Energy Plant near Tonopah, Nev.

Utility-scale solar power plants have run into well-publicized environmental challenges, but usually the issue is water use or the impact on terrestrial critters. At Ivanpah, BrightSource has been mired in issues over the desert tortoise. When it comes to birds and clean energy, it’s typically been big wind that has had issues.

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.


  • Reply August 31, 2012


    Wind turbines kills a few birds, but toxic dumping kills a whole ecosystem.

  • Reply August 31, 2012

    true blue red stater

    Sun goes down at night.
    Bats come out at night.
    So – please – how can a solar tower hurt bats?

    • Reply August 31, 2012


      I need to do some more research on these possible impacts we’re talking about here, but two quick thoughts: (1) the risk is primarily to birds; (2) the USF&W asks, “At night, if a zone of heated air remains around the tower, do birds or bats exhibit a behavioral response to that air space that could increase their risk of collision with the tower or do they avoid the area?” So in addition to the possible burn risk, there is a collision risk that apparently could extend into the night. But again, these are questions the USF&W is asking, an hoping to get answers by monitoring.
      Pete Danko

  • Reply August 31, 2012


    Additional power is necessary one way or another.
    If they stop these projects, then fossil fuels are going to pick up the slack right?
    Even if there is a possibility that tower power solar has an effect on local wildlife, we already KNOW that burning more coal/gas does.

    So I find it a little ‘fishy’ that the Fish and Wildlife service would prefer to continue to defer to fossil fuels rather than to just continue to monitor current installations as new plants go up.

  • Reply August 31, 2012


    Is this what they mean by being hoisted by your own petard? The outrage that someone might find fault with your favorite cause. Just awful….

    • Reply August 31, 2012


      Who is outraged? And at whom?

  • Reply August 31, 2012

    BrightSource Energy

    According to Rewire, the US Fish and Wildlife Service has actually clarified their position and are not asking for a moratorium on approving more power tower facilities.

    From the story:
    An official with the U.S. Fish and Wildlife Service contacted ReWire August 31 to clarify the agency’s position on assessment of solar power tower projects. FWS’s Assistant Regional Director for External Affairs Paul McKim told ReWire that FWS is not asking for a moratorium on solar power tower projects, but merely urges its fellow agencies to proceed with caution in approving such projects until more research is done on their effect on wildlife. McKim conceded that Sorensen’s suggestion that more data be collected on wildlife impacts “before approving more projects” could be read as a suggestion for a moratorium, but said that was not FWS’ intent. Sorensen’s letter has since been removed from the California Energy Commission website.

    – Keely Wachs, Sr. Director of Corporate Communications for BrightSource Energy

    • Reply August 31, 2012


      Keely, thanks for passing this along. I will update our story accordingly.
      Pete Danko

Leave a Reply