The U.S. Interior Department announced Wednesday it was approving two large solar projects in the Mojave Desert that may displace or harm more than 2,000 desert tortoises.
In a formal Record of Decision, or ROD, issued February 19, Interior approved two projects on more than six square miles of public land in California and Nevada for the Stateline and Silver State South solar projects, which the Arizona-based firm First Solar wants to build near the Mojave National Preserve south of Las Vegas. They are the 49th and 50th large renewable energy projects approved on public lands during the Obama administration.
According to an assessment of the projects released by the U.S. Fish and Wildlife Service in 2013, the two projects are expected to displace, injure, or kill up to 2,115 federally Threatened desert tortoises. Most of the mortalities will happen to young tortoises and will likely be killed without even being detected, the agency noted.
"When President Obama first took office in 2009, there were no solar projects approved on public lands, and no process in place to move forward the hundreds of applications pending from businesses that wanted to harness renewable energy to help power our nation," said Interior Secretary Sally Jewell in a press release Wednesday. "With today's milestone of 50 utility-scale renewable energy projects approved on public lands since our standing start in 2009, and with a number of those already producing energy for the nation's electric grid, our clean energy future is bright."
The Stateline solar project would occupy 1,651 acres of land on the California side of the state line near Primm, NV, next door (by Mojave Desert standards) to the towering Ivanpah Solar Electric Generating System formally commissioned on Thursday. The Silver State South project would sit on 2,388 acres on the Nevada side of the valley, much of it on an alluvial fan that provides prime habitat for the Ivanpah Valley's remaining tortoise population. Both projects would incorporate First Solar's cadmium telluride photovoltaic panels.
Both projects have also been redesigned in an attempt to mitigate damage to tortoise habitat. The 250-megawatt Silver State South project, which First Solar will be building for the project's Florida-based owner Next Era Energy Resources, likely poses the biggest long-term threat to the valley's tortoises in that it constricts some of the valley's remaining tortoise habitat corridor to a 3.6-mile-long band less than 1.5 miles across at its narrowest point. As tortoises do not usually migrate long distances, maintaining genetic connectivity between populations is generally thought to require corridors wide enough that multiple individual tortoises' lifetime territories can fit "abreast" within them. After Silver State South's construction, the corridor would accommodate one tortoise's territory at best, assuming that habitat wasn't degraded by construction.
One possible effect of even the most careful construction on the two projects, with potential deleterious effects on the Ivanpah Valley's tortoises, is a moderate long-term local increase in the raven population. Ravens pose a significant predation threat to young tortoises, and the presence of hundreds of thousands of photovoltaic panels where once there was little shade could boost raven survival rates in the area.
The ROD makes the two projects an official action of the Interior Department, and so clears the way for potential lawsuits over the project such as the one the group Defenders of Wildlife said that it was considering in November. We'll keep you posted.