CARBON, Wyoming (Reuters) - They used to mine coal in the abandoned town of Carbon. Now this patch of southern Wyoming is a battleground in the debate over what many hope will be the clean energy source of the future: wind power.
At the heart of the dispute are plans to build a network of wind farms in the American West that conservationists fear could disrupt threatened habitat such as sage brush, a dwindling piece of the region's fragile ecosystem.
This has made the greater sage grouse -- which as its name suggests is totally dependent on sage brush -- an unlikely poster child for some U.S. environmentalists, in much the same way that the rare spotted owl became a symbol in the 1980s of pitched battles with the logging industry.
Wyoming is home to 54 percent of the greater sage grouse population in North America. The bird's status is being evaluated for inclusion on the U.S. government's threatened or endangered species list, which would give it more protection.
The problem: The chicken-sized bird lives in the vast tracts of wind-whipped open spaces that make Wyoming highly attractive to the wind industry.
Near Carbon, the focus is on a 198-turbine, $600 million wind farm proposed by Horizon Wind Energy.
"They want to build it around here but we need to be thinking truly green. It is not just about our carbon footprint," said Alison Holloran of the National Audubon Society in Wyoming, as she pointed to clumps of grayish sage brush along a dirt road.
Wind power will play a huge role in any move by the United States to reduce its emissions of the greenhouse gases that most scientists believe are the main causes of rapid climate change. The burning of coal and the use of other fossil fuels such as oil are the largest single source of carbon emissions, so the race is on for "clean energy" alternatives.
In the public mind, wind is regarded as about as "green" an energy source as you can get. But some environmentalists see shades of brown in the industry.
They say the wind turbines and the development that goes with them, including roads and transmission lines, will further fragment critical sage habitat and disturb the grouse and other wildlife.
Horizon says the grouse issue requires more study.
"There is no peer-reviewed research on how sage grouse respond to turbines," said Arlo Corwin, Horizon's development director for the western region. "We believe that obtaining this research is essential to see if wind turbines and sage grouse are going to be able to coexist."
There have been several wind power skirmishes in the United States. Off Cape Cod in Massachusetts, there is a battle over plans for an offshore wind farm that opponents say will disrupt navigation and shipping. There have also been concerns about bird/turbine collisions in some places.
Wind now delivers about 1.25 percent of the United States' electricity supply, but the industry is growing fast, according to the American Wind Energy Association. It says wind power generation now offsets about 54 million tons of carbon a year.
In Wyoming, there are about 20 wind farms and four additional projects under construction, the association says. It ranks the state 12th in U.S. wind production but seventh in potential generation -- meaning a lot of untapped capacity.
Wind turbines already spin in Carbon County not far from Horizon's proposed development area, where the treeless countryside looks stark. The town of Carbon was abandoned over a century ago and only a few brick foundations remain.
In this harsh landscape, sage sustains life. The greater sage grouse and around 20 other bird species depend on it for survival, and the sturdy plant also sustains big game species such as elk and mule deer during the cold Wyoming winter.
Corwin said Horizon's planned wind development, known as the Simpson Ridge project, would make use of existing transmission lines that run through the area, removing at least one concern.
Horizon is evaluating when to apply for a permit to develop the site, which is also attractive because landowners have agreed to host the turbines on their property.
Last year, Wyoming said it would restrict development on greater sage grouse habitats it has designated "core population areas."
U.S. government wildlife officials say that other kinds of development have not been favorable for the grouse.
"The impact of fragmentation is very, very clear. We know that they won't occupy habitat close to an interstate for example. They are a landscape species and need big open intact habitats," said Brian Kelly, a field supervisor for the U.S. Fish and Wildlife Service in Wyoming.
Kelly said such concerns applied to all developments, including gas, oil and even housing -- not just wind.
About 20 percent of the state is regarded as "core" for the bird.
"If we conserve that 20 percent we effectively conserve 40 percent of the birds in North America. That's why it is significant," Kelly said.
The state government estimates that only about 14 percent of Wyoming's "economically viable wind areas" -- which is based on factors like wind strength, speed and duration -- is within core sage and grouse grounds while 86 percent is outside.
"We don't need to pick one or the other, grouse or wind. We can have robust sage grouse populations and robust wind development in Wyoming -- no problem," said Aaron Clark, an energy advisor to the governor of Wyoming.
The wind industry has disputed these figures and some of the definitions used by wildlife and state officials.
Horizon's Corwin noted that sage, which has lost about half of its historic range by some estimates, is also under threat from climate change. And reducing greenhouse gas emissions by harnessing energy sources such as wind is seen as the best way to slow or stop global warming.
Editing by Doina Chiacu