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

Solar Project Will Cause Unavoidable Damage to Wildlife

The Mojave fringe-toed lizard stands to lose some of its Chuckwalla valley habitat to the Palen Solar project | Photo: Global Herper/Flickr/Creative Commons License

The proposed Palen Solar Electric Generating System will cause damage to wild bird populations that cannot be mitigated, and poses significant risk to fringe-toed lizards and desert kit foxes as well. That's the gist of testimony provided by state and federal staff, scientists, and environmental activists at a state agency hearing on the project in late October.

According to the transcript of the California Energy Commission's public hearing held Tuesday, October 29 in Palm Desert, which was posted to the CEC website Monday, the project in Riverside County's Chuckwalla Valley s expected to cause unavoidable harm to wild birds through collisions with mirrors and other equipment, as well as burn injuries from the project's concentrated solar energy -- and CEC staff have no idea how that damage can be successfully remedied.

The project footprint is expected to interfere with the movement of wind-blown sand through the Chuckwalla Valley, which will likely degrade habitat for the Mojave fringe-toed lizard downwind. And people in attendance raised concerns over whether the project would continue the ongoing threat to local desert kit foxes, as well as questioning whether project proponents have agreed to set aside enough land for desert tortoises to make up for the loss of nearly six square miles of potential habitat.

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October 29 was the second day of CEC evidentiary hearings on the project proposed for the Chuckwalla Valley by Palen Solar Holdings, a joint venture of BrightSource Energy and Abengoa. (Transcripts for the first day of hearings are not yet online.) The project would place about 160,000 mirrored heliostats the size of billboards in concentric rows surrounding two 750-foot towers. The heliostats would focus sunlight on boilers atop the towers to generate steam, which would turn turbines to generate up to 500 megawatts of electrical power.

As ReWire has reported extensively, those mirrors and concentrated solar "flux" pose the risk of serious injury and death to wild birds and other flying wildlife that either venture into the zone of intense solar radiation or mistake the mirrors for water and collide with them.

And according to CEC staff members who reiterated at the hearing what they wrote in the Commission's Final Staff Assessment for the project, there's basically no way to redesign the project to reduce that risk. Instead, the agency will try to come up with ways to make the best of a bad situation for local birds once the project is built. A Technical Advisory Committee (TAC) made up of representatives of the Bureau of Land Management, the U.S. Fish and Wildlife Service, the state Department of Fish and Wildlife, and representatives from Palen Solar Holdings will be established to discuss how to cope with wildlife mortalities.

Whether the TAC's meetings will be open to the public has not yet been determined.

During the hearing, CEC staff member Chris Huntley responded to a question from the Center for Biological Diversity's Ileene Anderson about overall plans to mitigate damage to avian wildlife after the fact. His reply:

We do believe this is an unmitigable project. So what we're trying to do is offset in any way we can impacts to the species that we believe are going to be impacted. The development of the bird and bat plans, avian plans, that compensatory mitigation approach, the TAC committee, will basically become developed and be flushed out during those TAC meetings, and will be based also on the data that we accumulate through the long-term monitoring.

In other words, the TAC will see how much of a monkey wrench Palen throws at avian wildlife and will then try to come up with plans to help those species weather the apparently inevitable losses.

According to USFWS migratory bird biologist Tom Dietsch, a likely member of the Palen TAC, the Migratory Bird Protection Act has no provisions for allowing mitigation to offset deaths of birds protected under the law. "[S]o we cannot, as an agency, accept mitigation at any take of migratory birds in violation of the MBTA," Dietsch said at the hearing. In other words, it's illegal to harass, harm, or kill a bird listed under the MBTA, and there's no escaping the law by agreeing to mitigation programs.

Complicating the agencies' ability to forecast likely wildlife death and injury figures is the fact that Palen Solar Holdings partner BrightSource isn't keeping track of mortalities at its Ivanpah Solar Electric Generating System (ISEGS) project, which uses similar if smaller-scale technology to that planned for Palen. Though to be fair to BrightSource, Dietsch pointed out that the firm is hardly alone in not doing the most stringent monitoring possible.

As for whether the amount is adequate to mitigate for those impacts is an extremely difficult question to -- to answer, both in terms of understanding the scale of the impacts, because at this -- at this point, none of the -- the current projects are doing operational monitoring, standardized monitoring, including the ISEGS Project, so there's no way of quantifying what that impact would be.

Birds weren't the only wildlife discussed at the hearing. Palen would sit on part of what is known in the ecology trade as a sand transport corridor, a "river" in which sand flows along generally predictable paths creating habitat used by sand-adapted species like the Mojave fringe-toed lizard. The fringe-toed lizard is well adapted to sandy soils, able to run atop loose sand or "swim" beneath the surface. The related Coachella fringe-toed lizard is under threat due to alterations in the Whitewater River sand transport corridor, and wildlife advocates fear a similar fate may await Mojave fringe-toeds downwind of Palen.

Blocking a sand transport corridor generally means habitat downwind will degrade through a process called "deflation," in which the wind continues too remove sand from downwind locations without after the supply upwind is blocked or diverted.

A photo introduced into evidence at the hearing by U.C. Riverside biologist Allan Muth shows that it doesn't take much to block sand transport. The photo shows a standard chain-link fence across the Whitewater River in Palm Springs; despite the fence's standard very loose mesh, with holes hundreds or thousands of times wider than a typical grain of local sand, the thin chain link stops enough sand grains to build up a berm the height of the fence.

Chain link fence in Palm Springs affecting sand transport | Photo: Allan Muth | CEC

Even such a seemingly porous structure can obviously alter a sand transport corridor significantly. And as Muth pointed out, those effects can make themselves felt for a considerable distance downwind:

Fringe-toed lizards occur in a very specific range of sand size, where the average sand grain size for fringe toed lizards is a tenth of a millimeter to a millimeter in grain size. Below that or above that, they either don't occur there or it alters their behavior.

So when you get a sediment transport across the site, it's transporting particle sizes of all ranges from silt, you know, less than half a millimeter on up to small gravel, pebbles, whatever. That doesn't do anything any good in an aeolian sand system. The wind has to come in and sort those grains down wind. So if there's any impact at all from the sand transported across the site by those very small intermittent streams, it will be well downwind from the direct impact for the site.

The Mojave fringe-toed lizard is a state species of special concern, and managed by the BLM as a "vulnerable" species.

The Center for Biological Diversity's Ileene Anderson also raised the issue of local desert kit foxes. In the years since a previous version of the Palen project was approved by the CEC, a distressing die-off of the beleaguered canine took place a few miles east at the Genesis Solar project when local kits foxes came down with canine distemper. Though the source of that outbreak is still a source of controversy, the possibility remains that techniques used to haze desert kit foxes from the Genesis site contributed to the epidemic. That raises the prospect that those same hazing techniques might do damage to kit foxes at Palen.

Anderson also suggested that the CEC revisit a prior agreement that Palen Solar Holdings preserve an acre of land for the desert tortoise as mitigation for each acre of desert tortoise habitat Palen would destroy. "Because of the desert tortoise's continuing declines... I would like to see the Staff revisit the one-to-one mitigation ratio... because I think it gives short shrift to the environment," testified Anderson.

ReWire will report on any news of note that took place during the first day of the hearing when CEC makes that day's transcript available.

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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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