A federal assessment shows more than 3,000 desert tortoises that are threatened with extinction would be disturbed by a California solar project, and up to 700 of the young turtles would be killed during construction.
The U.S. Bureau of Land Management assessment released Tuesday is far more than BrightSource Energy Co.'s prediction that an estimated 38 of the rare reptiles would be disturbed by construction at the 5.6-acre Ivanpah Valley site near Primm, Nev.
Questions over the California tortoises highlight tensions in the U.S. between wilderness conservation and the quest for cleaner power.
The dispute is likely to echo for years as more companies seek to develop solar, wind and geothermal plants on land treasured by environmentalists who also support the growth of alternative energy. At issue is what is worth preserving and at what cost, as California pushes to generate more electricity from renewable sources.
Federal officials this month ordered BrightSource to halt construction activity on two-thirds of the project.
In a statement, company spokesman Kelley Wachs said the government projections "are not consistent with the actual numbers of tortoise found on the project site."
"It appears that the largest concentrations of tortoise are outside the project and in areas that we designed the project to avoid," Wachs said.
The Riverside Press-Enterprise reported that the BLM's new assessment estimates that up to 162 adult tortoises in the project area will have to be captured and moved and up to 700 juvenile tortoises would be killed during construction.
The U.S. Fish and Wildlife Service will use the new estimates to determine whether finishing the project puts the species in jeopardy. If not, the agency is expected to set new limits on how the animals may be killed, injured or harassed.
Environmentalists wanted the energy complex relocated because they said it will harm tortoises. BrightSource made design changes intended to alleviate environmental concerns.