News and analysis about energy in California with an eye toward renewables.

BrightSource Keeping Burned Bird Photos Secret

"It might be disturbing for someone who never cooked chicken before," described biologist Ileene Anderson. | Photo: Anna Harris/Flickr/Creative Commons License

ReWire has reported a number of times on the controversy over possible threats to wildlife from solar power tower facilities that concentrate huge amounts of sunlight on a central boiler.

Now there's a new wrinkle: Solar power tower developer BrightSource Energy tested the effects of their concentrated solar on a number of dead birds as part of their studies of the proposed Hidden Hills solar facility in Inyo County, and the company has since refused to release the photos to the public because they're too inflammatory.

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The story saw daylight yesterday in a report by David Danelski at the Riverside Press-Enterprise. Danelski, who'd dug through audio recordings of California Energy Commission (CEC) hearings on the Hidden Hills project near Tecopa, noted that CEC officials recessed a public hearing on February 11 so that they could view photos of singed chickens, quail, and pigeons that had been hung near the power tower at a BrightSource facility in Israel.

The birds, which had been euthanized before the test, were exposed to varying levels of concentrated solar power to simulate the effects on live birds flying through the area of "solar flux" near an operating power tower. BrightSource reported that only the highest levels of flux tested resulted in heat damage to feathers. Written descriptions of the damage were provided to CEC staff and intervenors in the Hidden Hills case, but according to Danelski BrightSource balked when the CEC asked to view photographic documentation of the bird carcasses after exposure to the solar flux.

It took the threat of a subpoena to get BrightSource to show the photos to CEC staff and intervenors in the Hidden Hills case, and even then the company insisted that the images not be made public. As CEC spokesperson Sandy Louey told Danelski,

Commission staff had to recognize BrightSource Energy's sensitivity to the possibility that the photos were inflammatory and would be misused if placed in the public domain.

Biologist Ileene Anderson of the Center for Biological Diversity, an intervenor in the Hidden Hills case, was also allowed to see the photos. She told Danelski that the images showed birds with heat-damaged feathers, adding, "It might be disturbing for someone who never cooked chicken before."

There's much to quibble with about the methodology of BrightSource's study. For one thing, the company's test facility in Israel is considerably smaller than Hidden Hills would be: the power tower there has a capacity of six megawatts rather than the 250 megawatts each Hidden Hills tower would reach, and the field of heliostats in Israel is much smaller. Some critics, including the Center for Biological Diversity, have pointed out that birds traversing a field of heliostats are likely to be exposed to solar flux for periods well in excess of a minute, the maximum period tested by BrightSource.

And as I mentioned to Danelski when he contacted me for the reaction included in his piece, it seems to me that testing flux intensities on euthanized birds -- while certainly more humane than some testing methods -- would fail to reveal certain important aspects of how non-dead birds will interact with the facility. The assumptions in testing seem to be that birds will traverse the solar field in a straight line at a constant speed. But might not the glare from an illuminated power tower or hundreds of thousands of mirrors cause disorientation? Birds may chart their course by paying attention to the direction from which sunlight; what happens when a bird finds itself surrounded by a ring of sunlight? Might a bird circle in a zone of relatively low damage be long enough for that low damage to accumulate?

Most curious, though, is the answer to the rhetorical question I offered Danelski: What does the company have to hide? If the photos were indeed described accurately in the documents provided to the CEC, wouldn't that bolster BrightSource's case?

I offered BrightSource reps an opportunity to make their case in this piece, with no response as yet. We'll provide updates should they choose to do so. Not that the company hasn't been working on the issue. As Danelski's piece was going live Tuesday, the CEC posted a proposal from BrightSource that offered additional mitigation for potential wildlife mortality. BrightSource insisted in the document that Hidden Hills poses no greater threat to wildlife than non-tower projects such as Genesis and the now-dormant Blythe Solar Project, but said it was offering those additional measures "in order to cooperate with the agencies." Those additional measures include buying and preserving mitigation land, monitoring for raptors in the area, and other "enhancement and conservation strategies." It looks as though the dead chickens aren't the only things feeling a little heat.

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About the Author

Chris Clarke is a natural history writer and environmental journalist currently at work on a book about the Joshua tree. He lives in Joshua Tree.
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