Calif.'s West Chocolate Mountains eyed for large-scale solar, geothermal expansions

A 59,000-acre strip of public and private land near Southern California's Salton Sea could accommodate enough solar and geothermal energy to power millions of homes and businesses, according to federal officials who are reviewing a plan for what could become a major new renewable energy zone in the United States.

The West Chocolate Mountains Renewable Energy Evaluation Area, currently under consideration by the Bureau of Land Management, sits sandwiched between the Salton Sea to the west and the Marine Corps' massive Chocolate Mountains Aerial Gunnery Range to the east, and includes nearly 21,000 acres of BLM land. The National Renewable Energy Laboratory has determined the evaluation area has high solar and geothermal power potential.

BLM this month released a draft environmental impact statement (EIS) for the West Chocolate Mountains evaluation area that indicates solar and geothermal power plants in the arid Colorado Desert region could produce thousands of megawatts of electricity.

The draft EIS, which is open for public comment through Sept. 29, is expected to be finalized by early next year, said Joe Vieira, a BLM renewable energy project manger in Monte Vista, Colo., overseeing the evaluation process.

But the West Chocolate Mountains evaluation area represents the first steps in a much broader BLM plan that is designed to guide solar and other renewables development across the West.


Indeed, the West Chocolate Mountains study area is part of more than 21 million acres of mostly federal and private lands that BLM identified in a December draft programmatic EIS as potentially suitable for solar-power development. That programmatic EIS also identified 24 solar energy zones on federal land in six Western states (E&ENews PM, Dec. 16, 2010).

BLM announced last week that it would produce a supplement to the programmatic EIS that will take a closer look at other potential solar energy zones within the 21 million acres. The new document will explore, among other things, the use of disturbed sites as part of the Arizona Restoration Design Energy Project, and conserving large sections of pristine lands in the California Desert Renewable Energy Conservation Plan area to be used as mitigation for other solar projects, said Ray Brady, leader of BLM's energy policy team in Washington, D.C.

The goal is to direct development into areas where wildlife, habitat and other landscape conflicts are minimal, creating a systematic approach to renewables development that Interior Secretary Ken Salazar said last week would "outlive the Obama administration" (E&ENews PM, July 14).

The West Chocolate Mountains evaluation also represents the beginning stages of a concentrated effort by the agency to study and designate local, smaller-scale solar energy zones where BLM can encourage the siting of multiple projects close to one another, Brady said.

"The West Chocolate Mountains is a relatively small area in terms of acreage, but it's a critical component in this larger effort," he said. "It gives us the chance to start looking at some of those additional 21 million acres to see how that additional acreage should it be managed, and whether any of it should be a specific development zone, or taken off the table."

Military, environmental tradeoffs

But the West Chocolate Mountains study site, as with any large-scale energy development plan, presents numerous tradeoffs.

Reasonable foreseeable development scenarios for the site calculated by NREL and outlined in the draft EIS indicate that renewables development could interfere with important military training operations in the region. As such, large-scale wind-power development has largely been ruled out at the site, according to BLM.

Both the Navy and the Marine Corps have expressed strong reservations about how development of the West Chocolate Mountains area would affect the Chocolate Mountains Aerial Gunnery Range, where pilots have trained since World War II.

BLM also acknowledges in the draft EIS that a full build-out of the public and private lands in the evaluation area, as well as within a 40-mile radius of the area, "would result in a substantial permanent conversion of desert habitat to industrial/commercial uses," which in turn "could have a considerable impact on a variety of special status species through direct habitat loss and/or habitat fragmentation," according to the document.

Environmentalists raised concerns during last year's public scoping period about the impacts on the dwindling habitat of the federally threatened Mojave Desert tortoise, as well as other sensitive species like the flat-tailed horned lizard and the burrowing owl.

Terry Weiner, Imperial County projects and conservation coordinator for the Desert Protection Council in San Diego, cautioned in formal comments to BLM that, "The fabric of the fragile California desert is being strained and torn and risks shredding from the plethora of large projects being planned."

In addition, large-scale development in the valley could place a significant strain on surface and groundwater supplies in the arid Colorado Desert region.

Much will depend on the types of renewables technologies targeted for the area. BLM states in the draft EIS that it plans to encourage any solar-power projects -- by far the most water-intensive of the primary renewable energy sources -- to use dry-cooling systems to wash mirrors and cool equipment.

BLM calculates that if three 500-megawatt solar power plants were built at the site using a wet-cooled system, they would consume an estimated 5.5 billion gallons of water a year. If those same plants used a dry-cooling system, they would only consume collectively about 1 billion gallons a year over the life of the projects.

"We understand the [energy] choices the nation's making right now, and we want to do it right and we're listening to the public that questions us and the public that also wants renewable energy," said Vieira, the BLM project manger. "We've heard very loudly and clearly from the environmental community their concerns about the way BLM has responded to making lands available to solar development. And we are trying to be careful."

Large energy potential

To date, BLM says there are no renewable energy project proposals for the West Chocolate Mountains evaluation area. Western Geothermal Partners in 2005 requested a geothermal lease on a 640-acre section on the northern end of the evaluation area. That lease would be awarded to the Reno, Nev.-based company under the terms of the draft EIS.

Still, few dispute that the area is an excellent potential source for solar and geothermal power. "Our team would not have taken on this project if we did not think there was some significant energy potential here," Vieira said.

The area sits along several major fault lines, including the San Jacinto and Imperial faults, where friction from tectonic plate motion has established a number of "local geothermal hot spots," according to the draft EIS.

Temperatures at relatively shallow depths of 8,000 feet have been measured in excess of 680 degrees Fahrenheit -- more than hot enough to produce steam to drive electricity-producing turbines.

Of the nearly 21,000 acres of public land in the evaluation area, BLM has identified 1,026 acres as suitable for three 50-megawatt geothermal power plants -- enough to power about 60,000 homes.

Such development would represent a major step forward for geothermal power in California. Currently 31 smaller geothermal plants in the state produce about 500 megawatts of electricity, according to BLM.

The region's solar-power potential is even more impressive.

BLM has identified 17,163 acres in the West Chocolate Mountains evaluation area as suitable for solar plants, and the agency estimates that such plants could produce as much as 7,038 megawatts -- enough to power nearly 3 million homes.

Such a concentration of development would be a major step forward in BLM's effort to establish the California desert as the solar-power capital of the world.

BLM this year has identified eight solar projects elsewhere in California for high-priority permitting, with hopes of getting construction under way by year's end. These priority projects would have a capacity to produce 2,173 megawatts, or enough to power nearly 870,000 homes.

The agency last year approved six large-scale solar plants in California that when completed in the next five years will have the capacity to power 1.2 million homes.

A solar energy industry official who spoke only on background because she had not finished reading the voluminous draft EIS, said many technical questions remain concerning transmission capacity and available markets for power that would be produced at the West Chocolate Mountains site. There is also the question of how much of the roughly 31,000 acres of private land mixed into the evaluation area would be available for development.

But Rhone Resch, president and CEO of the Solar Energy Industries Association, said in a statement last week on the progress of large-scale solar projects that the Obama administration "has put more emphasis and focus on advancing solar energy in the United States than any previous administration."

Training disruptions

The Defense Department also has raised concerns about large-scale energy development in the West Chocolate Mountains area, chiefly that the 450,000-acre Chocolate Mountains Aerial Gunnery Range, which was established during World War II and is still used today by the Marine Corps and Navy to train fighter pilots, would be adversely affected.

Both Marine Corps and Navy Special Warfare units train at the range, and some "long-range ground mobility training is conducted outside of the range on BLM-managed property," according to the draft EIS.

What's more, Camp Billy Machen, a Navy SEAL desert warfare training facility, is located about a half-mile east of the West Chocolate Mountains renewable energy evaluation area, according to the draft EIS.

Thus, the military "has concerns about the impact on our mission posed by potential geothermal, solar and wind energy projects" in the renewable energy evaluation area, wrote Patrick Christman, director of the Marine Corps' West Regional Environmental Coordination Office at Camp Pendleton, Calif., in a letter to BLM during the public scoping period last year.

"Heights of renewable energy structures and the transmission lines, which connect these sources to the grid pose potential aviation obstacles to Marine Corps low-level aircraft entering and exiting the range airspace," Christman wrote, adding that the "effect on training and safety will have to be determined" for any structure taller than 50 feet.

Such a height limit would all but rule out large-scale wind-power development, which utilizes wind turbines that can tower 200 or more feet.

In addition, spinning wind turbine blades have been shown to interfere with long-range radar systems.

"In general, wind turbines raise the ambient electro-magnetic 'noise level,' which decreases the probability of radar detection," wrote Christopher Stathos, fleet environmental coordinator and deputy regional environmental coordinator for the Navy's Southwest Region in San Diego.

The military's concern about tall structures is a primary reason why BLM is proposing not to develop wind power in the evaluation area, said Vieira, the renewable energy project manager.

"That [gunnery range] facility is really important to the nation's defense," he said. "Wind turbines interfere with long-range radar, and it's a potential hazard for pilots in the area. That would be why there's no wind there."

Click here to read the draft EIS.

Streater writes from Colorado Springs, Colo.

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