Hot Topic : Geothermal Power Plants in Mono County Stir a Boiling Debate

An exploding volcano created Long Valley on the eastern flank of the Sierra Nevada half a million years ago, leaving behind steaming fumaroles, geysers and half a dozen boiling springs that flow into Hot Creek.

The creek--a popular swimming hole for thousands of tourists--is part of a prime geothermal area. It also is an alternative energy source that has attracted commercial developers who have built a $16-million power station and are planning four or five more projects.

That might sound like good news for rural, economically strapped Mono County. Geothermal development could mean an additional $850,000 a year in tax revenues, officials say.

But Mono County, 300 miles north of Los Angeles, also is a premier recreation area, and the idea of “industrializing” any part of this play land disturbs many, including the Mammoth Lakes town council, fly fishermen, resort operators and environmental groups.

Stage Agency Joins Suits

The state Department of Fish and Game has joined other opponents in filing lawsuits to block two of the planned projects. The suits charge that the county failed to assess the full impact these developments could have on the environmental and recreational resources that attract millions of tourists to the eastern Sierra. A Superior Court judge ruled that the environmental impact report for one of the operations was inadequate and ordered the county to reevaluate the project. A decision is pending in the second suit.

State fish and game officials warned in an October, 1988, letter to the federal Bureau of Land Management that the geothermal projects pose a “serious threat” to the Hot Creek ecosystems. “The potential for irreversible and unmitigatable adverse impacts . . . greatly increases as several geothermal producing projects are constructed,” the letter said. One of the proposed plants would be on federal land controlled by the BLM.

Pacific Energy Inc. of Los Angeles, operator of the existing plant in Long Valley, defends its operation and its plans for several more plants. “Our . . . geothermal power plants are completely non-polluting,” said Michael J. Walker, director of Pacific’s geothermal division. “And they reduce the need for fossil-fueled generation.”

Long Valley is not the place for such development, said Bob Tanner, a resort developer and Sierra pack train operator. He favors asking Congress to designate Mono County a national recreation area to restrict industrial growth.

Outdoor recreation is big business here. Tourists spend $125 million a year in Mono County, according to the state Department of Commerce. During the winter, 1 million skiers drive or fly from Los Angeles to Mammoth Mountain and June Lake. In the summer, forest rangers say, another 5 million people flock here to camp, fish and ride horseback. Mammoth Lakes, an upscale resort town, is a vacation home for thousands.

Long Valley and Hot Creek are a part of this tourist scene; Hot Creek Gorge attracts 250,000 hikers and bathers each year.

Nearby, the state’s Hot Creek Fish Hatchery produces about 1 million catchable trout a year for planting in eastern Sierra streams. State biologists say the hatchery, which is dependent on water from Hot Creek, is threatened by geothermal development, a charge developers and county officials deny.

Hatchery officials are afraid that drilling wells and extracting heat from the geothermal system will lower the temperature of Hot Creek, which they say now helps to warm the ice-cold water to a constant 58 degrees Fahrenheit at the hatchery.

This enables trout to reproduce year-round, rather than just during a few weeks in the spring and fall.

The relatively warm temperatures also stimulate breeding of insects for native trout to feed on in Hot Creek, making it one of the nation’s blue-ribbon trout streams. “We’re afraid . . . a drop in temperatures would alter . . . the entire stream and marsh ecosystems as well,” said Curtis Milliron, a state fish and game biologist.

No one is sure exactly how the geothermal system under Long Valley works. Even the county’s energy experts cannot predict what the impact of the projects will be, but they say the developments will be closely monitored and quick action taken if temperatures or pressures change.

“We can detect these things in advance of irreversible changes,” said Dan Lyster, the county’s energy planner. The county is requiring the developers to install monitoring wells to insure that any changes are detected, he said. “We can mitigate any problems, just as they do in the oil and gas fields,” he added.

Such assurances do not satisfy opponents.

“Until we are convinced there will be no adverse impact on the hatchery, we are not prepared to take the gamble,” said Pete Bontadelli, state fish and game director.

Volcanic Action

The Long Valley Caldera--a 19-mile-by-10-mile depression between the mountains--was created by volcanic action nearly 500,000 years ago. The chambers of magma, or molten lava, that fueled the volcano are still active, far below the surface of a partially filled crater.

Hydrologists studying the strata under the caldera have found two permeable zones containing water between the layers of rock and sediment. These aquifers--fed by snow melt and rain--are heated by the magma, and the boiling water rises to the surface through the fractures.

The hottest water--400 degrees Fahrenheit--comes from the shallower aquifer, while the temperatures in the deeper zone range up to 240 degrees. Scientists do not know if the two are connected.

The geothermal plant taps the hotter water at 600 feet, pumps it through heat exchangers and then reinjects it 2,400 feet into the deeper aquifer. The exchangers use the heat to turn isobutane liquid to vapor in a second closed loop. The vapor then travels under pressure to the generator turbines. The isobutane is cooled and recycled.

The existing plant, built without controversy by Pacific Energy in 1984, is a low structure of girders, tanks and tubes. Insulated pipelines snake across the hillsides, linking the plant to four production wells and three injection wells. The company has transplanted tall pines and landscaped the area to minimize the plant’s visual impact.

‘No Impact on Hatchery’

“We’ve had four years of success, environmentally,” said Walker of Pacific Energy. “There has been no real environmental impact . . . no impact on the hatchery, which is 3 1/2 miles down the road.”

Four more plants are on the drawing boards, three by Pacific Energy and one by Bonneville Pacific Corp. of Salt Lake City. The Mono County Board of Supervisors has granted Pacific Energy a permit to build its second plant and authorized Bonneville Pacific to start a 10-megawatt unit adjacent to the fish hatchery. In addition, Unocal and at least one other firm have geothermal leases on federal lands in the Mammoth Lakes-Long Valley area.

The five projects would produce a total of 57 megawatts of power, according to Lyster. That is enough energy to power a city of nearly 60,000 people. Southern California Edison Co. would buy the electricity.

Opponents and Southern California Edison agree that the electricity is not needed now. But federal laws require utilities to buy such alternatively generated energy. And, the federal 1978 Public Utilities Regulatory Policies Act, designed to encourage alternative energy development, requires utilities to buy such power at 1978 prices.

Geothermal opponents contend that the plants would not be profitable if the utility paid market prices for the electricity. Edison’s contracts with Pacific Energy and Bonneville set the kilowatt-hour price at 7 to 9 cents, nearly three times the current cost of producing electricity, said Edison spokesman Sebastian Nola.

Defends Projects

The higher rate applies to the first 10 years of the 30-year contracts, according to David Hirschi, general counsel for Bonneville. “We may make a profit in the early years, but in later years, this gets leveled out . . . assuming utility prices rise,” Hirschi said. He defended the projects, saying that the need for environmentally clean alternative energy may increase if foreign oil prices rise.

It was Bonneville’s application to locate a geothermal plant near the fish hatchery that touched off the controversy. After stormy public hearings, the supervisors voted 3 to 2 to allow Bonneville to build.

Former Supervisor Tim Alpers, who originally opposed the project, was the swing vote. He said he changed his mind because the county needs more tax revenues.

Soon after the board approved the Bonneville project, lawyers for Cal Trout, a statewide anglers’ group, the Sierra Club and the state Department of Fish and Game filed suit in Mono County Superior Court.

While this case was awaiting a decision, the county supervisors approved Pacific Energy’s second project by a 5-0 vote. Supervisor Andrea Lawrence, who had opposed the Bonneville project, said she favors a “go-slow” geothermal development policy, with strict controls on each project.

Van de Kamp Files Suit

State Atty. Gen. John K. Van de Kamp, acting for the state Department of Fish and Game, filed suit against the county and Pacific Energy in mid-January to block the Pacific Energy permit. Like the earlier suit against Bonneville, the state argued that the county and project developers had not complied with the requirements of the California Environmental Quality Act.

In the meantime, Mono County formed the Long Valley Hydrologic Advisory Committee--an ad hoc group of federal, state and private geothermal experts--in an effort to find some way to resolve the controversy. The committee instructed Lyster to write a letter to the supervisors, saying that the county’s plans to monitor the projects would protect the environment. Fish and game agency officials and other opponents disagree, and the decision rests with the county Board of Supervisors.

Geothermal Plants Generate Controversy

Mammoth-Pacific Geothermal Plant uses two closed-loop systems. In primary loop, hot (340-400 F) water is pumped from 600-foot deep aquifer to heat exchangers in the plant. Water leaving the heat exchangers, cooled to 140-180, is returned to a deeper aquifer at 2,400 feet.

In secondary loop, a fluid called isobutane is heated by heat exchangers to produce a pressurized gas that drives turbine-generators to produce electric power. Isobutane is then condensed into liquid state for continuous reuse in heat exchangers. Isobutane and water from aquifer never come in direct contact.