The Mammoth Geothermal Complex is a complex of 3 geothermal power stations located at

Casa Diablo Hot Springs Casa Diablo Hot Springs is a hot springs and active geothermal location, near Mammoth Lakes and the Eastern Sierra Nevada, in Mono County, eastern California. Geography It is within the northern part of the Long Valley Caldera volcanic featur ...

about east of

Mammoth Lakes Mammoth Lakes is a town in Mono County, California, and is the county's only incorporated community. It is located immediately to the east of Mammoth Mountain, at an elevation of . As of the 2020 United States Census, the population was 7,191, r ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. The complex is owned by

Ormat Ormat Technologies, Inc. is an international company based in Reno, Nevada, United States. Ormat supplies alternative and renewable geothermal energy technology. The company has built over 190 power plants and installed over 3,200 MW. As of J ...

and operated by its subsidiary Mammoth Pacific.

Description

The complex consists of three

binary cycle A binary cycle is a method for generating electrical power from geothermal resources and employs two separate fluid cycles, hence binary cycle. The primary cycle extracts the geothermal energy from the reservoir, and secondary cycle converts the ...

geothermal power stations, each with a

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, or maximum effect, is the intended full-load sustained output of a facility such as a power station,

of 10 MW. Mammoth Pacific 1 (MP1) was commissioned in 1984 and was the first air-cooled geothermal power station in the world. Mammoth Pacific 2 (MPII) and PLES-1 were both commissioned in 1990 and use the same air-cooled technology. In 2005, the geothermal well field was expanded into "Basalt Canyon" just west of the three power stations. Two production wells were drilled and connected to the existing power plants. In 2014,

replaced the 30-year old equipment of MP1 in order to improve its efficiency.

Casa Diablo IV

In 2006, Ormat proposed the construction of a 30 MW

geothermal power plant called "Casa Diablo IV" that would double the generating capacity of the geothermal complex. In 2014, the Mammoth Community Water District (MCWD) sued the Great Basin Unified Air Pollution Control District (GBUAP) and ORNI 50 LLC (Ormat) over concerns that the power plant would compromise the water supply of

. GBUAP and Ormat disputed this, arguing there was no connectivity between the deep geothermal reservoir and MCWD's groundwater

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

based on extensive research conducted on the site. On June 25, 2015, the Mono County Superior Court ruled in favor of GBUAP and Ormat. In addition, on August 31, 2015, the Interior Board of Land Appeals denied an appeal made by MCWD. Casa Diablo IV is expected to be operational by the end of 2021. As of July 14th, 2022, Ormat announced that commercial operations at Casa Diablo IV had begun.

Geology

The Mammoth Geothermal Complex is located at the base of a large

resurgent dome In geology, a resurgent dome is a dome formed by swelling or rising of a caldera floor due to movement in the magma chamber beneath it. Unlike a lava dome, a resurgent dome is not formed by the extrusion of highly viscous lava onto the surfac ...

near the center of the

Long Valley Caldera Long Valley Caldera is a depression in eastern California that is adjacent to Mammoth Mountain. The valley is one of the Earth's largest calderas, measuring about long (east-west), wide (north-south), and up to deep. Long Valley was formed 7 ...

. The

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

was formed from the swelling or rising of the

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

floor due to movement in the

magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upw ...

beneath it. The geothermal heat produced from the magma chamber below the dome causes

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...

to boil and turn to steam, creating

fumaroles A fumarole (or fumerole) is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

such as those seen in Fumarole Valley and along Hot Creek about to the northeast. The geothermal complex utilizes this heat to power its

power generators.

References

{{Generating stations in California, state=autocollapse 1984 establishments in California Buildings and structures in Mono County, California Energy infrastructure completed in 1984 Geothermal power stations in California

Description

Casa Diablo IV

Geology

See also

References