Under President Barack Obama, wind energy has exploded as a pollution-free energy source that can help reduce the gases blamed for global warming. But it is not without environmental costs.
An AP investigation last year documented dozens of eagle deaths at wind farms, findings later confirmed by federal biologists. Each one is a violation of federal law, but the Obama administration to date has prosecuted only one company, Duke Energy Corp., for killing 14 eagles and 149 other birds at two Wyoming wind farms.
The wind energy industry sought the change to reduce its liability.
The industry said the rule helps protect eagles because, in exchange for legal protection for the lifespan of wind farms and other projects, companies obtaining permits would be required to make efforts to avoid killing protected birds.
"This rule appropriately balances wildlife conservation with the realities of the private sector," said John Anderson, director of siting policy at the American Wind Energy Association. Anderson said the 30-year timeframe was similar to permits granted for endangered species. Eagles are not endangered.
The permits would be reviewed every five years and adjusted if necessary. But the conservancy in its lawsuit claims those reviews would be internal and not subject to public input.
Wind farms are clusters of turbines as tall as 30-story buildings, with spinning rotors as wide as a passenger jet's wingspan. Though the blades appear to move slowly, they can reach speeds of up to 170 mph at the tips, creating tornado-like vortexes.
No wind energy company has obtained permission authorizing the killing, injuring or harassment of eagles, although five-year permits have been available since 2009. That has put the companies at legal risk and has discouraged private investment in renewable energy.
It's unclear what toll, if any, wind energy companies are having on eagle populations locally or regionally. Gunshots, electrocutions and poisonings almost certainly kill more bald and golden eagles than wind farms. But the toll could grow along with the industry.
A recent assessment of the status of the golden eagle in the western U.S. showed that populations have been decreasing in some areas but rising in others.
The Fish and Wildlife Service said it would not comment on pending or ongoing litigation, filed in federal court in San Jose, Calif.