A big challenge for any new renewable energy project in the West is moving power to customers.

There simply isn't enough space on existing transmission lines to handle the extra electricity utilities predict will be needed, and states want to produce, in the next 20 years. Two years ago, the Western Governors Association agreed on a goal of 30,000 megawatts of new clean energy from utilities by 2015.

But they need the lines to carry the power.

Efforts are under way to expand the capacity of existing power lines to add new lines and energy corridors, some of which are opposed by landowners and environmental groups.

In May, State Land Commissioner Patrick Lyons said the lack of capacity on the transmission grid was one of the biggest constraints to renewable energy growth in New Mexico. "Incentives, credits and exemptions are passed not only to attract new business to the state, but to make green energy sources affordable and readily available to New Mexico families. Unless we can move the power, these efforts are futile," Lyons said at the time.

The State Land Office is in discussions with at least two companies about building transmission lines to connect to the grid for new wind, solar and geothermal energy.

The Sun-Zia project is a 500 kilovolt, 350-mile-long transmission line across New Mexico and Arizona to transport wind, solar and geothermal energy to market.

One company planning a wind farm facility on trust and private lands in Lincoln and Torrance counties is proposing a power grid through the center of the state.

Two types of lines are needed, according to Steven Michel, an attorney with Western Resource Advocates: smaller feeder lines to connect renewable energy facilities to the grid and large bulk transmission lines to carry the energy between states.

The New Mexico Legislature created a New Mexico Renewable Energy Transmission Authority in 2007 to help companies finance and build transmission lines. The authority has one project in the works, a 50-mile upgrade to an existing transmission line to connect a 100-megawatt wind facility in Torrance County, according to Lisa Szot, executive director of the authority. The High Lonesome Mesa project is being developed by California-based Edison Mission Energy.

Szot said her goal is to work with companies and state and federal agencies on upgrading existing transmission lines "rather than just put in new lines. We might need to widen the existing corridors to put in bigger poles, but at least it would still be in the same path."

In November, four federal land agencies released a final environmental impact statement for the proposed designation of 6,000 miles of energy corridors through federal public lands in 11 Western states. The agencies claim the proposed energy corridors would help with the siting of oil, gas and hydrogen pipelines and electricity-transmission lines through federal lands while protecting the environment.

The proposal was made under the Energy Policy Act of 2005, which directs the secretaries of agriculture, defense, energy and the interior to designate energy transport corridors.

To review the report, including detailed maps, visit the project Web site at http://corridoreis.anl.gov.