Green energy poses some sticky environmental questions

If built, the 460-mile line would carry about 3,000 megawatts, enough power to avoid the need for a handful of coal-fired plants and help utilities meet mandated targets for use of renewable fuel. "We have to connect the sun of the deserts and the winds of the plains to places where people live," Interior Secretary Ken Salazar said recently.

But the line would also cross grasslands, skirt two national wildlife refuges, and traverse the Rio Grande, all habitat areas rich in wildlife. The graceful sandhill crane, for example, makes its winter home in the wetlands of New Mexico's Bosque del Apache National Wildlife Refuge, right next to the path of the proposed power line. And much of the area falls under the protection of the Interior Department's Bureau of Land Management.

A priority for the Obama administration, renewable-energy development poses conflicts between economic interests and environmental concerns, not unlike how offshore drilling for oil and gas pits economics against environment. But because of climate concerns, environmentalists and government regulators could find themselves straddling both sides of the issue, especially in Western states where the US government is a major landowner.

"Everybody in New Mexico loves the sandhill cranes," said Ned Farquhar, a former aide to New Mexico Governor Bill Richardson, a Democrat. "We also love our renewable energy. So we have to figure this out."

Farquhar made that comment a month ago when he was working for the Natural Resources Defense Council. Since then, he has been appointed head of the BLM - in charge of figuring it out.

As the push for renewable-energy development intensifies, scientists and activists have begun to voice concern that policy makers have underestimated the environmental impact of otherwise "green" projects.

"There is no free lunch when it comes to meeting our energy needs," said Johanna Wald, a senior lawyer at the Natural Resources Defense Council. She added, however, that the renewables boom "offers a chance to do it right."

There is no question permit applications for renewable-energy projects are on the rise, especially on federal land in the West. According to Ray Brady, leader of the BLM's energy policy team, the bureau has received 199 applications for solar projects encompassing a total of 1.7 million acres, though only two of them have undergone environmental assessments.

The agency has already authorized 206 wind projects - 28 of them to generate power, the rest primarily to test a region's generation capacity - and at least 200 more are awaiting approval.

The fact that eight Western states have established "renewable portfolio standards" has accelerated the push for new projects, Brady said, because those policies are forcing utilities to find additional renewable power sources.

"For all of these reasons, BLM does have a challenge because of the additional work involved," said Brady, who predicted that the agency may hire as many as 100 people just to work on renewable-energy permits. "Clearly there's an interest in expediting and streamlining the process. However, we need to make the right decisions that are based on the best science."

One of the biggest challenges renewable-energy projects pose is that they often take up much more land than conventional sources such as coal-fired power plants. A team of scientists, several of whom work for the Nature Conservancy, has written a paper that will appear in the journal PLoS One showing that it can take 300 times as much land to produce a given amount of energy from soy biodiesel as from a nuclear power plant. Regardless of the climate policy the nation adopts, the paper predicts that by 2030, energy production will occupy an additional 79,537 square miles of land.

The impact will be "substantial," said Jimmie Powell, the Nature Conservancy's national energy leader and one of the paper's coauthors. "It's important to know where the footprint is going to be."

In some cases, scientists are just beginning to discover the unintended effect of projects such as wind turbines. Grassland birds such as the lesser prairie chicken and the greater sage grouse, both of which are candidates for listing under the Endangered Species Act, appear to avoid vertical structures such as wind turbines and transmission-line towers. This is proving to be a problem in states such as Kansas, an ideal site for wind power, because as more turbines are built, lesser prairie chickens will confine themselves to narrow ranges, fragmenting a population that must be connected to survive.