The impact of renewable energy projects on migrating birds is a story that has — to stretch an obvious metaphor – taken flight.
My Nov. 10 story on bird deaths at solar thermal and photovoltaic plants in Riverside and San Bernardino counties was picked up by USA Today, as well Pasadena public radio station KPCC – I did a taped interview — and even, I heard from a friend, got a mention on the The Drudge Report.
Now we have yet more information with the release Nov. 18 of BrightSource Energy’s October monitoring reports from the Ivanpah solar project in eastern San Bernardino County. As initially reported by Chris Clarke at KCET, the total dead bird count at the 377-megawatt solar thermal plant was 53, with 22 listed as having melted or scorched feathers.
That’s up from September’s tally of 34 mortalities, with 15 with melted feathers. The damage is likely caused by the birds flying through the intense radiation coming off the Ivanpah’s 300,000 reflecting mirrors — about 100,000 surrounding each of the plant’s three 459-foot solar towers. The tightly focused radiation heats liquid in boilers at the top of the towers, creating steam to run turbines.
The October tally also had a high number of small song birds, such as yellow-rumped warblers (13, 8 with melted wings) and house finches (8, 6 with melted wings). (Pictures below, warbler above, house finch below, from allaboutbirds.org, a website run by the indispensable Cornell Lab of Ornithology.)
Waterfowl were in the totals as well, though none were found singed. Two blue-winged teals, two coots and a spotted sandpiper were found dead, along with one loon found alive with a injured foot and eventually released, October’s sole survivor.
In the meantime, a new study published online provides updated figures on bird deaths at wind farms. “Estimates of bird collision mortality at wind facilities in the continguous United States” will be published in December in the journal Biological Conservation, but is already available online, with Clarke again doing an early report.
The authors — Scott R. Loss, Tom Will and Peter P. Marra — scoured various literature sources to find the most up-to-date mortality figures, particularly focusing on the impact of the repowering of older turbines with lattice-style foundations versus the newer, taller monopole machines. Numbers from the San Gorgonio Pass were not included, Loss replied to an emailed query on the matter, because the only available studies he could find on the pass were based on unadjusted raw data that would not have given a true picture of mortalities in the area.
But even without San Gorgonio, Loss and his co-researchers found mortality rates for monopole turbines in California leading the nation, averaging 108,715 per year, compared to 22,177 per year for the rest of the western states. Comparable rates for the Eastern states were 44,006 and for the Great Plains states, 54,115.
Breaking it down to bird deaths per turbine, California is again the highest, with 7.85 per turbine versus the Great Plains, which was lowest at 2.92 per turbine.
iI you want to put it in terms of megawatts, in California, we’re losing about 18.76 birds per megawatt of wind power produced. One megawatt can power between 750 and 1,000 homes.
The study also found that taller turbines were related to higher bird mortality rates.
Putting these figures in some kind of dispassionate, objective context is always difficult. No one likes to think of song birds — symbol of all that is free, fragile and beautiful in nature — flying through a solar field with their wings melting, like so many pint-sized Icaruses soaring too close to the sun. Images of migratory birds getting shredded by a turbine are equally grisly and distasteful.
At the same time, the issue pushes us to examine our expectations that what we call clean or renewable energy should be impact-free when, in fact, it isn’t and can’t be. Should the problem irrevocably tarnish public perceptions of large-scale renewable energy projects? Should we halt or at least slow the development of these plants on public land until we can figure out a solution? What kinds of mitigation or compensation should solar and wind developers be required to undertake in the interim?
The answers to such questions are complex and very much a matter of context. Every form of energy generation has direct or indirect environmental impacts of some sort — as do most forms of human economic development. The impacts we find personally and socially acceptable may change over time depending on shifting priorities and sensibilities.
Millons, if not billions of birds die yearly from collisions with buildings, windows and electric wires. We haven’t stopped building any of these structures. At the same time, the fact that the number of birds killed by turbines or at solar plants might appear relatively small in comparison should not be seen as a reason to say such deaths are less significant.
Renewable energy, particularly utility-scale solar, is still in its early stages of development. It is, some environmental advocates have said, a huge experiment, its long-term impacts unknowable at this point.
Officials at the U.S. Fish and Wildlife Service stress that the first step must be solid, scientific research. Every bird carcass found at large-scale solar projects on public land is now reported, stored in a freezer and turned over to the agency for autopsy. A good start, but more needs to be done.
For example, at solar thermal projects such as Ivanpah, the carcasses found on site may only be a portion of the deaths or injuries to birds flying over it. Some may have their wings singed, but make it through the project site only to come down and die nearby. Should biological monitors also be regularly surveying a certain radius around the project? Could such a zone be monitored electronically?
The birds with singed feathers at Ivanpah are all relatively small song birds. Is this an issue of size? Can larger birds make it through without damage or are we not finding them?
The response of solar companies to such questions so far has been to comply with all requests from the Fish and Wildlife Service, while downplaying the significance of the issue in general and doing whatever they can to minimize their costs and public involvement in research and mitigation plans.
During public hearings on BrightSource’s proposed Palen project, which would put two 750-foot solar towers near two major migratory bird refuges east of the Coachella Valley, the company lobbied hard to remove conditions from the permit requiring regular public meetings for a committee set up to monitor efforts to minimize bird deaths on the site.
Similarly, NextEra Energy has argued that any plans for monitoring bird deaths at its proposed photovoltaic Blythe project should be formulated not as permitting requirements but as part of an overall bird and bat conservation strategy to be finalized after the project is officially approved and again without public involvement.
At this point it is uncertain whether the companies’ positions will be formalized in the final state and federal permits for the projects. Officials from the California Energy Commission appear to be tilting that way, going along with both firms’ efforts to water down specific permitting requirements related to minimizing and monitoring bird deaths.
Hopefully, the commission will reverse this trend in its final permitting documents for both projects and require ongoing public meetings as more research becomes available. Clearly, the public is already involved. Complete transparency will be the companies’ and agencies’ best strategy for building long-term support for their projects.