IN THE MOJAVE DESERT, Calif. — The picture is unsettling and disturbing.
A small bird, barely the size of a human hand, had its wings reduced to a web of charred spines. No longer able to keep aloft, the bird was found on the ground after it had flown through the intense heat of a solar thermal project soon to go online in the California desert.
The photograph, taken at BrightSource Energy’s Ivanpah plant in east San Bernardino County, has raised the stakes for a similar project in Riverside County. Months from final state and federal approvals, the Palen solar thermal power system could put two 750-foot-tall solar towers and thousands of reflecting mirrors near two of the region’s key wildlife refuges and stopping points for birds migrating along the Pacific Flyway.
The project is roughly 50 miles from both the Salton Sea to the southwest and the Cibola National Wildlife Refuge in Arizona to the southeast.
“A migrating bird has to be in top form, having the flight feathers in really good shape,” said ornithology collections manager Kimball L. Garrett of the Museum of Natural History of Los Angeles County, who has not seen the picture from Ivanpah but has been concerned about bird deaths at large solar projects.
“If some of its flight feathers are damaged, what does that mean for the rest of the bird’s migration?” he said. “It weakens feathers. These are things people don’t study because — how can you?”
Trying to estimate how many birds could be injured or killed because of large-scale solar projects and what might be done to prevent deaths has become a pressing concern for solar developers and environmental agencies as these projects multiply. Developers hope to have the Palen project online in 2016.
Of 34 birds reported dead or injured at Ivanpah in September, 15 had melted feathers. Dozens of other bird carcasses, not singed but with critical injuries, have been found in recent months at two solar projects about to go online on public land between Joshua Tree National Park and Blythe, Calif., a town of 20,800 on Interstate 10 near the Arizona border.
Last month, 19 birds, 16 of them water fowl or marsh birds, were found dead at Desert Sunlight, a 550-megawatt photovoltaic plant about 50 miles east of Indio, Calif. The carcass of a Yuma clapper rail, a federally endangered, medium-sized marsh bird, was found at the project in May.
Environmentalists aired their concerns about potential bird deaths at Palen at a recent public hearing on the project, and days later, state officials issued a call for more information on how to minimize chances of birds being singed or burned. A key question the California Energy Commission raised in a Nov. 1 memorandum was how to measure when bird deaths might be excessive enough to consider a temporary shutdown of a plant.
BrightSource, federal, state and local agencies, and environmental and tribal groups are invited, but not required, to provide answers to the commission’s questions as part of legal briefs typically submitted during a permitting process for large solar plants.
The problem is the intense radiation — called solar flux — from the project’s 170,000 reflecting mirrors that will surround two 750-foot-tall towers that would become the tallest structures in Riverside County.Sunlight from the mirrors will superheat liquid in boilers at the top of the towers, creating steam that in turn will power a turbine.
Pacific Gas Electric has contracts with BrightSource to buy the electricity from the plant, which could power up to 200,000 homes.
BrightSource declined to comment for this story, and company representatives consistently have avoided discussing bird mortality.
Before a public hearing, the company submitted a presentation on possible methods for scaring birds away. Barking dogs or trained falcons might be effective, depending on the species, but the methods need more research, the report said. Radio-controlled airplanes or water-cannon or shotgun blasts also might prove effective, but only with sustained onsite monitoring. Fake owls might prevent mortality, but only until the birds get used to the statues.
Experts are dubious about most of those methods.
“Owls won’t work, barking dogs, cannons making a series of booms — birds tend to habituate to those things,” said Robert McKernan, director of the San Bernardino County Museum, who in the 1980s did some of the first studies on bird deaths at an early solar tower project.
“You’ve got to look at the relative width of that envelope that’s off the tower,” he said, referring to the solar flux coming off the mirrors that will surround the towers in concentric circles, spreading out over the project’s 3,800-acre footprint.
At the same time, both McKernan and Garrett said the bird deaths at solar projects need to be seen in the larger context of mortality rates for migratory birds in general, which are already high from natural and other man-made causes. Millions of birds die yearly flying into windows and buildings.
“A few golden eagles killed by wind turbines is significant — they are large, long-lived birds that don’t have high reproduction rates — whereas a dozen mallards or ruddy ducks probably on a population level is pretty insignificant,” Garrett said. “The problem is gauging cumulative impacts.”
Many migratory bird species are now in decline because of climate change, drought and habitat loss, McKernan said.
The Riverside East solar zone, as the public land between Joshua Tree and Blythe has been designated, is a solar-industrial corridor along I-10 that federal officials once envisioned would have up to 80% of its 148,000 acres in panels or mirrors.
Today, that seems unlikely. Industry trends are toward smaller solar projects and the U.S. Department of Energy’s loan-guarantee program has ended. Still, the region could see a significant number of projects.
The first phase of Genesis, a 250-megawatt solar thermal project, using large parabolic troughs instead of solar towers, is scheduled to go online by the end of the year, as will Desert Sunlight, which Next Era Energy owns with GE Energy Financial Services and Sumitomo Corp. of America. The 750-megawatt photovoltaic McCoy project is approved, and its first 250 megawatts are likely to begin construction next year, company officials said.
If approved, Palen would be the second solar tower project in the region. Santa Monica, Calif.-based SolarReserve also expects to break ground on a 150-megawatt project. Two other photovoltaic projects also are earlier along in the pipeline.
Predicting the number of birds at risk if all the projects were to go online is impossible, said Eric Davis, assistant regional director for migratory birds and state programs at the U.S. Fish and Wildlife Service.
“Bird migration studies have to wait for bird migrations,” he said. “It’s not like we’re going to have the answers in two weeks. This is going to be months and years of trying to better understand the problem and then make better management decisions as we gain more scientific understanding.”
Along with radiation injuries, scientists are concerned about bird deaths linked to confusion because of the shimmering expanses of solar panels in the desert. At photovoltaic projects such as Desert Sunlight, dark, flat solar panels are spread out over hundreds of acres in what may look like a big lake to migrating birds flying overhead.
Water or shore birds attempting to land on the panels either could hit them with enough force to injure themselves or, stranded on dry land, be unable to take off again.
Autopsies have shown the cause of death for many birds at Desert Sunlight has been blunt force trauma when the animals collide with panels mistaken for water, Davis said.
“With power towers, it’s different,” he said, referring to Ivanpah. “The solar flux has singed some birds. The heat has denatured the protein in their feathers, and they can’t fly.”
First Solar, the Arizona company building Desert Sunlight, has downplayed the possibility that the panels draw the birds. More than 60% of carcasses on the site have been found away from panels, said Steve Krum, director of global communications.