"Iberdrola's plan is really an incredible document," says Dave Stout of the US Fish and Wildlife Service (FWS). "By following this plan, they will reduce their liability under the Migratory Bird Treaty Act and they'll drastically reduce the chance that the Fish and Wildlife Service will go after them for taking migratory birds." The reference to "taking" is FWS language for bird deaths in wind farms.
Iberdrola Renewables, the US wind power arm of Spain's largest utility, agrees that its plan is forward-looking. "There are more and more projects going into sensitive areas," says the company's Andy Linehan. "And at some point, relatively small amounts of mortality at each project could accumulate to significant amounts."
While many states have requirements to protect fauna, others, such as Texas, are virtual regulation-free zones. Iberdrola's plan, which it describes as a first for the US industry, applies to projects that go online from next month and will include a mechanism for reporting any findings to FWS.
Best practice
"What we're doing is taking our best practices at some of our projects on the west coast and east coast, where permitting requirements are pretty rigorous," says Linehan. "And we're going to be applying them consistently across the country, even in places where permits don't require such things," he continues. "If we find that a project has mortality which is out of line with what was expected before the project was built, or out of line with regional averages, then we'll engage in discussions with FWS and, potentially, state agencies."
Some say Iberdrola's plan has potential to help shape forthcoming industry-wide guidelines. A federal advisory committee of stakeholders is to make suggestions to FWS for a voluntary industry plan before the end of next year, says Laurie Jodziewicz of the American Wind Energy Association. That plan, chartered through the US Department of Interior, is expected by late next year or early 2010. "Iberdrola presented its plan to the advisory committee as an interesting model that could potentially be used," says Jodziewicz. "But I think all eyes are really on the federal advisory committee to see what they might do."
Meanwhile, Iberdrola is participating in a study to vary the cut-in wind speed for wind turbines at its 34.5 MW Casselman Wind Project, about an hour from Pittsburgh, so see if that makes it easier for bats to avoid them. The experiments require operating the turbines sub-optimally, leading to curtailments of generation and loss of revenue.
Mortality reduced
"Iberdrola has stepped right up to the plate and offered their site in a very proactive fashion, where others have declined the offer," says Ed Arnett of Bat Conservation International, which ran the study and expects to release a report next month. "We've found a significant reduction in the mortality rates under the turbines where we changed the cut-in speed," Linehan says. "We've crunched the numbers to see what it has cost us to do it. And once the report is done, there'll be some good information to share."
Preliminary results correspond with studies in Canada and Germany that showed about a 50% reduction in fatalities from changing the cut-in speed, according to Arnett. "It's a gargantuan data set, but I'm as excited as anybody to get the final numbers on this curtailment," Arnett says.
Beyond proper siting and targeted curtailment, the only other possible remedy for reducing bat deaths is through ultrasound devices attached to turbines. "We're seeing some promise with these devices," Arnett says. "But we do not currently have an operationally functional and effective deterrent at this point. And we may not get one."
Arnett's theory played out last summer when Iberdrola tested devices that emit white noise to keep bats away from turbines at Maple Ridge, a 320 MW New York project the company co-owns with Horizon Wind Energy. "You had to have multiple sound emitters to cover one turbine," Linehan says. "So this curtailment idea is another way to address the same problem. We'll be able to see which one is most cost effective, but they both look somewhat promising."
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