Industrial Wind Farm Kills Bats While Feds Ignore Problem

Published October 1, 2014

A Nevada wind farm has killed triple the number of bats allowed under an agreement with federal wildlife officials, yet the federal government has imposed no significant penalties.

Facility Responds to Bat Deaths

Located 260 miles northeast of Las Vegas, the 152-megawatt Spring Valley Wind Energy project supplies energy to approximately 40,000 homes. The project, however, has been forced to make changes in its operations after killing 566 bats in 2013, nearly three times the 169 allowed per year.

Operational changes included adjusting the “cut-in” speeds of the turbines on nights when bat activity is high, so the turbines start turning only when sustained winds reach about 11 mph instead of the normal cut-in speed of 7 mph.

“We will continue to conduct research on both bird and bat activity at the facility, as well as on potential mitigation strategies, to continue to reduce our impact,” said Rene Braud, director of environmental compliance at Pattern Energy, which operates the Spring Valley farm.

“While reducing the cut-in speed does affect production, it is not a major impact on the project’s overall output, and we are willing to accept this in order to reduce our environmental impact,” Braud added.

Wind Turbines Versus Wildlife

The trade-off between wind turbines and wildlife mortality has been a topic of debate among environmentalists. In this case, conservationists foresaw the turbines’ negative impact on birds and bats and fiercely protested construction of the Spring Valley wind power facility. The wind power facility sports 66 turbines and sits on more than 7,600 acres of federal land, nestled between the Schell Creek and Snake mountain ranges.

Each tower stands up to 425 feet tall and holds a rotor the diameter of a football field. The tips of the blades can reach speeds up to 170 mph. According to biologists, even if a bird or bat succeeds in not hitting a blade, the changes in the barometric pressure when the blades are spinning can cause their insides to explode.

The Center for Biological Diversity and the Western Watersheds Project sued to stop construction of the Spring Valley facility. A federal judge decided to allow construction to proceed, during which time the impact on bats could be studied. Settlement talks produced an agreement between Pattern Energy and wildlife officials to track and limit bird and bat deaths. Under terms of the agreement, Spring Valley was allowed to kill 178 birds and 169 bats annually.

Contested Value of Dead Bats

Braud said the majority of bats killed by the Spring Valley wind turbines are abundant Mexican free-tail bats.

“The facility has had no impact at all on any threatened or endangered bat species, and the impact on all other kinds of bats has been on the very low end of the national range for wind energy facilities,” she said.

Nevertheless, bats of all species are very important to the ecosystem. As a demonstration of the bats’ importance, physicist and environmental advocate John Droz cited an important study measuring the economic impact bats have on agriculture.

The study, “Economic Impact of Bats in Agriculture,” by Justin G. Boyles, Paul M. Cryan, Gary F. McCracken, and Thomas H. Kunz , measures the economic impact of bats’ insect suppression on a county-by-county basis across the country.

The study found the Spring Valley wind project and its death toll on bats could cost Clark County farmers $471,443.

The Spring Valley wind facility has done a better job minimizing bird deaths, with just 40 reported deaths last year. This amount is well below the 178 bird deaths allowed at the wind farm annually. However, one of those bird deaths was a golden eagle, which is specifically protected under federal law.

Over the objections of Native Americans and environmentalists, in December 2013, the Interior Department exempted wind farms from penalties associated with bald and golden eagle deaths for up to 30 years with use of a take permit. Pattern Energy took advantage of the Interior Department’s decision and applied for a 30-year take permit earlier this year.

Alyssa Carducci ([email protected]) writes from Tampa, Florida.