Mammoth Pacific’s geothermal facilities are nestled in the magnificent Eastern Sierras. Located near the intersection of Highway 395 and State Route 203 in Mono County, CA, the facilities were designed to blend into the landscape.

In fact, many visitors who come to Mammoth Lakes to enjoy skiing as well as other outdoor recreational and sporting activities never even notice the geothermal facilities. This is a tribute to the design that minimizes the visibility of these power plants.

We’re proud of our facilities, but seeing is believing! That’s why we offer tours to interested individuals and groups who want to know more about how we generate clean, renewable electricity.

The Mammoth Pacific power plants transform heat from geothermal fluid (hot water from underground) into clean, renewable electricity. The energy is produced by three separate power plants, using hot water from the same source. The three facilities are: G1 (MP1) which is rated at 10 megawatts and G2 (MPII) and G-3 (PLES-1) which are each rated at 15 megawatts. All totaled, the facilities generate enough power for approximately 40,000 homes. The power is sold to Southern California Edison under long-term contracts.

There are two geothermal technologies used to convert the geothermal fluid’s thermal energy (or heat) into electricity: “flash” and “binary.” Mammoth Pacific facilities utilize the binary technology, which emits virtually nothing into the atmosphere. And the Mammoth Pacific’s G1 facility was the world’s first air-cooled geothermal facility to incorporate two closed loop systems.

Here’s how the binary system at Mammoth Pacific’s facilities works:

Geothermal fluid is pumped from the ground (see red) in a primary binary loop. This hot water passes through heat exchangers (to heat the secondary loop, shown as aqua in this diagram) before being immediately returned to the earth with no loss of fluid. In the secondary binary loop, isobutane fluid is indirectly heated in the heat exchangers to produce a high-temperature, high-energy, gas vapor that drives the turbine-generator to produce electricity.

The gas vapor is then cooled back to a liquid by air condensers (cooling fans) and pumped back to the heat exchangers for continued use or “recycling”. Throughout the process, operation's data is transmitted real time to a control room for monitoring. Staffed 24 hours a day, the control room contains the starters and controls for all electrical motors and switchgears in the plant.

Construction of Mammoth Pacific's evaporative cooling project.

Since the start of operations, Mammoth Pacific has developed an industry-wide reputation for innovation and cutting-edge technologies. The facilities regularly participate in various research projects in cooperation with agencies such as the U.S. Department of Energy, National Renewable Energy Lab, Idaho National Environmental Engineering Laboratory, Lawrence Livermore National Laboratory, Brookhaven National Laboratory, Duke University and the California Energy Commission. The projects evaluate innovative technologies such as high temperature polymer production pump bearings, the use of reclaimed water for cooling purposes, the use of geothermal water for cooling purposes, mineral recovery, supersaturated vapor expansions in turbines, membrane-based non-condensable gas removal systems, micro-earthquake analysis, and corrosion resistant heat exchanger coatings--all with the purpose of improving operations and efficiency.

As a result of this leadership, the facility’s general manager, Bob Sullivan, received a prestigious award from the respected Geothermal Resources Council for “outstanding contribution to the development of geothermal resources.” See the Mammoth Times article.

This is one of many awards and commendations received by Mammoth Pacific and its geothermal facilities.

Because of our reputation as an industry leader, people from all over the world travel to Mammoth Lakes to see our facilities. We’ve given tours to people from countries including the Philippines, Japan, Indonesia, Iceland, Israel, Italy, Kenya, Portugal and New Zealand. In October 2003, dignitaries from Kenya visited us to learn more about our environmentally sound operations.

Mammoth Pacific has been recognized by elected officials, trade associations and community groups for its outstanding record on environmental protection and operations excellence.

• California State Assembly
• U.S. Forest Service
• California Department of Conservation
• Eastern Sierra Advocates Network (ESAN) / formerly PESTER
• The Governor’s Environmental and Economic Leadership Awards
• Geothermal Resources Council

In 1991, the California State Assembly passed a Resolution commending Mammoth Pacific on the start up of two of its facilities, recognizing that the facilities “will utilize naturally occurring geothermal hot water to produce electricity without the need for fossil fuel or environmentally damaging emissions.”

In addition, the U.S. Forest Service presented Mammoth Pacific with an award in recognition of our “commitment to quality geothermal development, sensitivity to natural resource values, and responsiveness to public concern.”

Since the start of commercial operations, the California Department of Conservation’s Division of Oil, Gas and Geothermal Leases has presented numerous awards to Mammoth Pacific for its outstanding record of environmental protection, resource management, and safety. In 2004, Mammoth Pacific received the award for the fifth consecutive year.

Marilu Habel with the California Department of Conservation presents Mammoth Pacific with an Outstanding Lease Maintenance Award for the 5th consecutive year.

A local environmental group, Preserving the Eastern Sierra Tradition of Environmental Responsibility (now called the Eastern Sierra Advocates Network), presented Mammoth Pacific with its 2000 Seedling Award “in appreciation of outstanding environmentally compatible design.” Special commendation was made for the facilities’ excellent industrial design, the choice of color, and its effective use of natural landscaping to screen the facility from the Highway 395 Scenic Corridor.

Mammoth Pacific was selected to receive the prestigious Governor’s Environmental and Economic Leadership Award for 2003. The award recognizes "individuals, organizations, and businesses that have demonstrated exceptional leadership and made notable, voluntary contributions in conserving California’s precious resources, protecting and enhancing our environment, and building public-private partnerships."

Mammoth Pacific representatives met with California Governor Schwarzenegger after the awards were presented by California Environmental Protection Agency Secretary Terry Tamminen and Resource Agency Secretary Mike Chrisman. An overflow crowd of nearly 300 people attended a December 2003 ceremony to recognize the awardees. See Governor’s press release for more information about all the award winners.

Mammoth Pacific was honored as a recipient of the 2003 Governor's Environmental and Economic Leadership Award.  Shown here from left to right is Actor Beau Bridges, Secretary for Resources Agency Mike Chrisman, Larry Nickerson and Bob Sullivan of Mammoth Pacific, Governor Arnold Schwarzenegger, Cal/EPA Secretary Terry Tamminen, and Department of Food & Agriculture Secretary A.G. Kawamura.

Mammoth Pacific was selected as a winner under the technology innovation category, which focuses on the development or application of new technologies for improving environmental quality and protecting public health and safety. The geothermal company was recognized specifically for its multi-year evaporative cooling research project that tested different technologies for increasing power generation during the hot summer months—when California most needs the power. This project successfully increased power output by about 20 percent in the summer and will benefit the industry as a whole.

Mammoth Pacific also received a Certificate of Recognition under the Governor’s Environmental and Economic Leadership Award program in 2001 for the evaporative cooling technology research project.

As a result of Mammoth Pacific’s leadership in the geothermal industry, the facilities’ general manager, Bob Sullivan, received a prestigious award from the respected Geothermal Resources Council in 2000 for “outstanding contribution to the development of geothermal resources.” Here’s the Mammoth Times story.

Mammoth Pacific’s geothermal facilities were the featured cover story of the May/June 2000 Geothermal Bulletin, a publication of the Geothermal Resources Council, a respected trade association. The article titled “Showcase of Geothermal Development” discussed the Mammoth Pacific facilities, our operations and our strong relationship with the community.

As a result of the facilities’ design, our reputation for environmental and operations excellence, and the scenic beauty of the area, photographs of Mammoth Pacific’s facilities have been featured on the cover of government reports on renewable or geothermal energy. Dated February 2003, a joint U.S. Department of Energy and the U.S. Department of Interior report assessing renewable energy potential on public lands featured a photograph of Mammoth Pacific’s facilities on its cover.