Any way you look at it, the Gateway West transmission line project is as grand as its name suggests.

The $2 billion project will string together more than 4,000 electric transmission towers, each up to 175 feet high, nearly 1,200 miles across Wyoming and Idaho. When completed in 2013, it will move enough electricity to power 2.4 million homes, improving an overburdened electric transmission system that has not changed much in the last 30 years, and expanding the use of clean, wind-generated power throughout the West.

As impressive as it is, Gateway West is just one in a series of major transmission line projects that when completed over the next nine years will move as much as 13,000 megawatts of electricity -- enough to power more than 10 million homes -- to energy-hungry population centers across the western United States.

The transmission lines are badly needed. There has not been any major transmission line construction in the region in three decades, said Walt George, a national project manager for the Bureau of Land Management who is overseeing Gateway West for the agency, as well as a similar-sized transmission line project called Gateway South.

BLM must approve the projects because nearly half of the proposed route of the transmission lines will cut through hundreds of acres of public land.

The projects have created an awkward conflict between industry and government leaders who tout them as a necessary step to -- among other things -- facilitate the development of wind energy and other clean alternatives to fossil fuels, and some environmentalists who worry the transmission towers will degrade wildlife habitat and the aesthetic appeal of public lands.

One of the environmental community's biggest gripes is that no one can say how much of the electricity that will move through the high-voltage power lines will come from existing and planned wind farms in Wyoming, Utah and Idaho, and how much will come from coal-fired power plants in the region that have access to a steady supply of Wyoming's Powder River Basin coal.

They are also concerned about detrimental impacts to sage grouse, which may soon be a federally listed endangered species.

"We are four-square behind the development of renewable energy. We understand that we have to greatly reduce our need and demand for fossil fuels," said Bruce Pendery, program director and staff attorney for the Wyoming Outdoor Council. "However, we don't think that goal should be pursued in a way that's totally oblivious to the environmental impacts, or that gives out a free pass related to environmental impacts. We think there still has to be a real concerted effort to reduce the impacts from these lines."

Energy officials and government regulators concede that a significant portion of the electricity moving through the proposed lines would be generated from coal, natural gas and other traditional methods.

"The project is bigger than just simply a means of moving wind-generated electricity," said Margaret Oler, a spokeswoman with Rocky Mountain Power, whose parent company, PacifiCorp, is building the Gateway West project.

The projects have to be about more than alternative energy, said Paul Kjellander, administrator of Idaho's Office of Energy Resources.

"We have a situation throughout the West where our [electrical] transmission system is at or near capacity at peak times of the day," he said. "We must have additional transmission if we want to have a reliable, robust electricity grid. It's just essential."

The proposed projects

In addition to Gateway West, major proposed electricity transmission line projects include:

• The Gateway South transmission project, which will stretch 1,200 miles from Wyoming to central Utah and down into Nevada. The $2 billion project will provide 3,000 megawatts, or enough to power 2.4 million homes. Developed by PacifiCorp, it is set for completion in 2014.

• The TransWest Express project, which will stretch from Glenrock, Wyo., to a point near Las Vegas. The 800-mile transmission line will supply 3,000 megawatts of electricity. It is being developed by the Anschutz Corp. and is scheduled for completion in 2015.

• The High Plains Express project, which will stretch 1,200 miles from Wyoming to Arizona. This $5 billion project will provide 3,500 megawatts of electricity to points in Wyoming, Colorado, New Mexico and Arizona. The project is scheduled for completion in 2017 and is being developed by a wide range of groups, including Trans-Elect Development Co., the Western Area Power Administration and the Wyoming Infrastructure Authority.

• The Wyoming-Colorado Intertie, which will stretch 180 miles from Wheatland, Wyo., to Sterling, Colo., and provide 850 megawatts -- enough to power 680,000 homes -- when it is finished in 2013. The proposed $300 million project is being developed by three groups: Trans-Elect Development Co., the Western Area Power Administration and the Wyoming Infrastructure Authority.

"When you add all that up, it's a very sizable amount of activity," said Steve Waddington, executive director of the Wyoming Infrastructure Authority, which is charged with overseeing transmission line development in the state. "It's long overdue."

Growing environmental concerns

One of the main potential obstacles for Gateway West and the other transmission line projects is a chicken-like, ground-dwelling bird that depends on the wide-open sagebrush plains for its survival.

The sage grouse -- first described by Lewis and Clark during their 1804 expedition -- is currently being reviewed by the U.S. Fish and Wildlife Service for potential addition to the endangered species list. The bird's habitat is primarily along the proposed paths of the transmission lines in Wyoming, Idaho, western Colorado, Utah, Nevada and six other states. The bird depends on the sagebrush for food, as well as protection from predators.

Because all of the proposed transmission lines cross federal lands at some point, BLM must conduct detailed environmental impact statements for each that will determine the extent of harm to wildlife, water and air quality. But if the sage grouse were added to the endangered species list, it would require BLM to mandate that potentially elaborate steps be taken to protect the sagebrush plains before authorizing the companies to erect the power lines.

A review of the proposed route of the Gateway West transmission line reveals that it will cut through large swaths of sage-grouse habitat, said Pendery, the Wyoming Outdoor Council attorney.

A number of environmental groups have already formally raised concerns about the Gateway West project, which is much further along in the regulatory process than the others. BLM in June held nine scoping meetings on the project in Wyoming and Idaho at which the public was allowed to submit comments.

Despite the uncertainty regarding FWS's sage grouse determination, Walt George, the BLM project manager, said, "We won't hold up the project waiting for the Fish and Wildlife Service to issue a decision." Instead, he said, the agency is working to keep project plans flexible in the event the sage grouse does become listed as endangered.

But as a general rule of thumb, George said, BLM is working with the energy companies to route the power lines along existing transmission corridors. He notes that about 60 percent of the proposed Gateway West route is adjacent to existing power lines or within an established transmission line corridor.

But even if the transmission lines follow these corridors, countless makeshift roads will need to be built during construction and kept in operation to allow for routine maintenance, said Katie Fite, biodiversity director for the Western Watersheds Project.

"You can only chop a piece of land into smaller and smaller bits for so long before the wildlife that was there goes away," Fite said. "This is something that anyone who cares about public lands should keep a close eye on."

Uncertainty surrounding climate change

One of the most confusing aspects of the proposed transmission line projects is the role they will play in addressing global climate change.

The new transmission lines will allow companies to build more wind farms like one the Anschutz Corp. plans to build in south-central Wyoming. Given that coal-fired power plants are the world's largest industrial source of greenhouse gas emissions, expanding the use of wind-generated energy is a critical component in efforts to solve global warming.

One reason for all the interest in wind-generated power is the fear of federal climate change legislation.

Congress spent much of the past year debating legislation that for the first time would regulate man-made emissions of greenhouse gases that contribute to warming the planet. Though Congress failed to pass legislation, the issue will come up for consideration again. And the prospect of limiting carbon dioxide emissions, either through a straight-up emissions cap, a carbon tax or a cap-and-trade program, has helped spur the industry to invest in alternative energy projects.

But transmission lines would create global warming concerns of their own.

That's according to a 20-page comment letter regarding the Gateway West project sent to BLM in June by the Center for Biological Diversity. One of the group's chief concerns is that as the planet warms and droughts become more common, the nation's 624 million acres of federal land will become critical routes for animals like the sage grouse and American pika to migrate north to cooler climates (see related story).

They say BLM must completely study the effects of the transmission line project on global warming. And they argue that cannot be done until a determination is made on how much of the electricity to be transported through the lines will be generated by environmentally unfriendly sources like coal-fired power plants and how much will come from alternative energy sources.

"All they've done, as far as I can see, is throw out vague assertions," said Amy Atwood, a senior attorney with the center's public lands program.

George, the BLM project manager, said the agency would direct the energy companies to take steps to address northward migration and other concerns that are identified in the environmental impact statement. But he also warned that there is only so much that can be done.

"No energy generation, whether renewable or otherwise, is without its environmental effects," George said. "It takes a tremendous amount of land to generate electricity from wind energy, and placing these large turbines on the landscape changes how the landscape looks. Even wind energy is not without its consequences."

The push to build power lines

Most of the current transmission projects stem from efforts in 2003 by Wyoming Gov. Dave Freudenthal (D) and former Utah Gov. Mike Leavitt (R) to measure alternative energy resources in their two states, Colorado and Montana, and to determine how to build the needed transmission lines to get this and other forms of electricity to the population centers, Waddington said.

The result of the collaboration was the Rocky Mountain Area Transmission Study, which in 2004 concluded that without new transmission lines "the region will not be able to tap lower cost coal and wind generation." The study recommended a number of transmission line upgrades and expansions across the West.

The Rocky Mountain Area Transmission Study and a 2005 study led by the Western Electricity Coordinating Council are listed in BLM scoping documents as among the primary reasons why the Gateway West project was needed.

Also, a study published last month by the Pacific NorthWest Economic Region planning organization concluded that the Pacific Northwest does not have the transmission capacity to bring electricity to population centers and that there could be severe economic consequences if the biggest proposed transmission lines -- including Gateway West -- are not built.

The study, titled "The Cost of Not Building Transmission: Economic Impact of Proposed Transmission Line Projects for the Pacific Northwest Economic Region," concluded that Idaho, Montana, Washington, Alaska and other Western states will face a greater likelihood of rolling blackouts because the energy grid will soon be overwhelmed by increased demand.

The Department of Energy in a 2006 study identified the need for more electricity transmission lines from Wyoming to the West and supported the concept of the Gateway West project. "This area is rich in coal and wind resources that, if developed, could provide important sources of low-cost energy and fuel diversity while improving domestic energy self-sufficiency and enhancing the economic development in the resource areas," according to the study.

Yet even if Gateway West and the other large transmission line projects are built, they might not be enough to meet growing demand. The Western Governors' Association, acknowledging rapid growth in many Western states, has recommended adding 30,000 megawatts of electricity from alternative sources like wind and solar during the next seven years.

Scott Streater is a freelance journalist based in Colorado Springs, Colo.