The Geysers is the world's largest geothermal field, containing a complex of 18
geothermal power
Geothermal power is electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation is currently used in 2 ...
plants, drawing steam from more than 350 wells, located in the
Mayacamas Mountains
The Mayacamas Mountains are located in northwestern California in the United States. The mountain range is part of the Northern Inner Coast Ranges, of the California Coast Ranges System.
Geography
The Mayacamas Mountains are located south of the ...
approximately north of
San Francisco
San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
,
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 ...
.
Geysers produced about 20% of California's renewable energy in 2019.
History
For about 12,000 years, Native American tribes built steambaths and thermal pools at the Geysers and used the steam and hot water for healing purposes, as well as spiritual and ceremonial practices, and cooking.
The thermal pools were used as a medicinal treatment for rheumatism and arthritis. While the heated muds were used to soothe skin rashes and other aches and pains, using the fumaroles as a natural energy source. When European Americans first entered the area, six Indian tribes inhabited the area around the Geysers, three bands of
Pomo people
The Pomo are an Indigenous people of California. Historical Pomo territory in Northern California was large, bordered by the Pacific Coast to the west, extending inland to Clear Lake, and mainly between Cleone and Duncans Point. One small grou ...
, two bands of
Wappo people, and the Lake
Miwok people
The Miwok (also spelled Miwuk, Mi-Wuk, or Me-Wuk) are members of four linguistically related Native American groups indigenous to what is now Northern California, who traditionally spoke one of the Miwok languages in the Utian family. The word ...
.
The Wappo also collected
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
which they called ''te'ke'' and a Wappo village, named ''tekena'ntsonoma'' (''teke'' sulphur + ''nan'' well containing water + ''tso'' ground + ''no'ma'' village) was located about southeast of
Cloverdale and on the present-day Sulphur Creek.
Today, Calpine Corporation, the largest generator of electricity from natural gas and geothermal resources in the US, generates power at the site.
The Geysers were first seen by European Americans and named in 1847 during
John Fremont
John is a common English name and surname:
* John (given name)
* John (surname)
John may also refer to:
New Testament
Works
* Gospel of John, a title often shortened to John
* First Epistle of John, often shortened to 1 John
* Second ...
's survey of the
Sierra Mountains and the
Great Basin
The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...
by William Bell Elliot who called the area "The Geysers," although the geothermal features he discovered were not technically
geysers
A geyser (, ) is a spring characterized by an intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only in ...
, but
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 ...
.
Between 1848 and 1854,
Archibald C. Godwin developed The Geysers into a spa named ''The Geysers Resort Hotel'', which attracted tourists including
Ulysses S. Grant
Ulysses S. Grant (born Hiram Ulysses Grant ; April 27, 1822July 23, 1885) was an American military officer and politician who served as the 18th president of the United States from 1869 to 1877. As Commanding General, he led the Union Ar ...
,
Theodore Roosevelt
Theodore Roosevelt Jr. ( ; October 27, 1858 – January 6, 1919), often referred to as Teddy or by his initials, T. R., was an American politician, statesman, soldier, conservationist, naturalist, historian, and writer who served as the 26t ...
and
Mark Twain
Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910), known by his pen name Mark Twain, was an American writer, humorist, entrepreneur, publisher, and lecturer. He was praised as the "greatest humorist the United States has p ...
.
The resort declined in popularity in the mid 1880s, and rebranded itself to appeal to lower-income people.
In 1938, the main building was destroyed in a landslide although the bar/restaurant, small cabins and the swimming pool stayed open, despite another fire in March 1957, until about 1979.
In 1960,
Pacific Gas and Electric
The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered in the Pacific Gas & Electric Building, in San Francisco, California. PG&E provides natural gas and electricity to 5.2 milli ...
began operation of their 11-megawatt geothermal electric plant at the Geysers.
Unocal Corporation
Union Oil Company of California, and its holding company Unocal Corporation, together known as Unocal was a major petroleum explorer and marketer in the late 19th century, through the 20th century, and into the early 21st century. It was headqu ...
dismantled the remains of the resort in 1980.
Five of the Geysers facilities were damaged in the
Valley Fire
The Valley Fire was a wildfire during the 2015 California wildfire season that started on September 12 in Lake County, California. It began shortly after 1:00 pm near Cobb with multiple reports of a small brush fire near the intersection of ...
of September 2015, suffering "severe" damage to their cooling towers. The main power houses were not damaged. The
Kincade Fire
The Kincade Fire was a wildfire that burned in Sonoma County, California in the United States. The fire started northeast of Geyserville in The Geysers on 9:24 p.m. on October 23, 2019, and subsequently burned until the fire was fully c ...
was reported burning at John Kincade Road and Burned Mountain Road in The Geysers, at 9:27 PM on October 23, 2019.
The fire started at 9:24 PM during an extreme wind event, and subsequently burned 77,758 acres (31,468 ha) until the fire was fully contained on November 6.
The Geysers Geothermal Power Development project was designated as a California Historic Civil Engineering Landmark by the San Francisco Section of the
American Society of Civil Engineers
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
in 1976.
Geothermal development
The Geysers is the world's largest geothermal field
spanning an area of around in
Sonoma,
Lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
and
Mendocino counties in California, centered in the area of
Geyser Canyon and
Cobb Mountain
Cobb Mountain is the tallest mountain in the Mayacamas Mountains of California.
Location
Cobb Mountain's main summit is located in Lake County, west of the town of Cobb. Like nearby Mount Saint Helena, Cobb Mountain is tall enough to receiv ...
. Power from The Geysers provides electricity to Sonoma, Lake, Mendocino,
Marin
Marin (French) or Marín (Spanish "sailor") may refer to:
People
* Marin (name), including a list of persons with the given name or surname
* MaRin, in-game name of professional South Korean ''League of Legends'' player Jang Gyeong-hwan (born 19 ...
, and
Napa counties. It is estimated that the development meets 60% of the power demand for the coastal region between the
Golden Gate Bridge
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the strait connecting San Francisco Bay and the Pacific Ocean. The structure links the U.S. city of San Francisco, California—the northern tip of the San Francisco Pen ...
and the
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
state line.
Unlike most geothermal resources, the Geysers is a dry steam field which mainly produces
superheated
A superheater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. Superheated steam is used in steam turbines for electricity generation, steam engines, and in processes such as steam reforming. There are ...
steam.
Steam used at The Geysers is produced from a
greywacke
Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...
sandstone reservoir, capped by a heterogeneous mix of low permeability rocks and underlain by a
silicic
Silicic is an adjective to describe magma or igneous rock rich in silica. The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent. Granite and rhyolite are the most common silicic rocks.
Silicic is the grou ...
intrusion
In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
.
Gravity and seismic studies suggest that the source of heat for the steam reservoir is a large
magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
chamber over beneath the surface, and greater than in diameter.
The first geothermal wells drilled in Geyser Canyon were the first in the Western Hemisphere.
The first power plant at the Geysers was privately developed by the owner of The Geysers Resort
and opened in 1921, producing 250 kilowatts of power to light the resort.
In 1960,
Pacific Gas and Electric
The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered in the Pacific Gas & Electric Building, in San Francisco, California. PG&E provides natural gas and electricity to 5.2 milli ...
began operation of their 11-megawatt plant at the Geysers.
The original turbine lasted for more than 30 years and produced 11
MW net power.
By 1999 the steam to power extraction had begun to deplete the Geysers steam field and production began to drop.
However, since October 16, 1997, the Geysers steam field has been recharged by injection of treated sewage effluent, producing approximately 77 megawatts of capacity in 2004.
The effluent is piped up to from its source at the Lake County Sanitation waste water treatment plants and added to the Geysers steam field via geothermal injection.
In 2003, the City of Santa Rosa and Calpine Corporation partnered on constructing a 42-mile pipeline that became known at the Santa Rosa Geysers Recharge Project (SRGRP). Since 2003, SRGRP has delivered approximately 11 million gallons per day of tertiary treated wastewater to replenish The Geysers’ geothermal reservoir.
In 2004, 85% of the effluent produced by four waste-water treatment plants serving 10 Lake County communities was diverted to the Geysers steam field.
Injecting treated water into the Geysers field increases the amount of power that can be generated.
The injection of wastewater to the Geysers protects local waterways and
Clear Lake by diverting effluent which used to be put into surface waters,
and has produced electricity without releasing greenhouse gases into the atmosphere.
Geothermal power stations
This is a table of all constituent geothermal power stations sorted by unit identification.
[
]Calpine
Calpine Corporation is the largest generator of electricity from natural gas and geothermal resources in the United States, with operations in competitive power markets.
A Fortune 500 company based in Houston, Texas, the company is owned by an ...
owns 19 existing units, most of which were acquired from PG&E
The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered in the Pacific Gas & Electric Building, in San Francisco, California. PG&E provides natural gas and electricity to 5.2 milli ...
and Unocal Geothermal in 1999. NCPA Units 1-4 are jointly owned by the Northern California Power Agency (NCPA) and Silicon Valley Power
Silicon Valley Power (SVP) is a not-for-profit municipal electric utility owned and operated by the City of Santa Clara, California, USA. SVP provides electricity service to approximately 55,116 residential and business customers, including larg ...
. Bottle Rock is wholly owned by Bottle Rock Power LLC, a joint-venture between U.S. Renewables Group and Riverstone Holdings
Riverstone Holdings is a multinational private equity firm based in New York City focused on leveraged buyout, growth capital, and credit investments in the energy industry and electrical power industry sectors. The firm focuses on oil and gas ...
.[
In addition, ]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 ...
owns the plans for a new 30 MW geothermal power station at the vacant Calpine 15 site that were acquired through a merger with U.S. Geothermal in 2018. The plans were previously developed by Ram Power before being sold to U.S. Geothermal in 2014.[
]
Seismicity
For the past several decades, small earthquakes (less than 2.0) are regularly recorded in the area. It has been estimated that 99% of all seismic activity at and surrounding The Geysers is around 3.0 or smaller. In fact, "the frequency of seismic events greater than 3.0 have been trending downward since 1990". Due to the remote location it is very infrequent for humans to feel the effect of this tectonic shake. Typically seismic activity in this area is measured using seismometers that can pick up on micro seismicity down to extremely minute levels. This has been demonstrated to be caused by the water injection process used to produce the geothermal electricity at the power plant.
According to the Lawrence Berkeley National Laboratory
Lawrence Berkeley National Laboratory (LBNL), commonly referred to as the Berkeley Lab, is a United States Department of Energy National Labs, United States national laboratory that is owned by, and conducts scientific research on behalf of, t ...
Earth Sciences division, seismicity
Seismicity is a measure encompassing earthquake occurrences, mechanisms, and magnitude at a given geographical location. As such, it summarizes a region's seismic activity. The term was coined by Beno Gutenberg and Charles Francis Richter in 19 ...
was very low prior to the use of the Geyser steam field for geothermal energy, although this may have been the result of low seismic coverage of the area. Before 1969, there were no earthquakes above magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
2 recorded by the United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
(USGS) in an approximately area around the Geysers. Studies have shown that injecting water into the Geysers field produces earthquakes from magnitude 0.5 to 3.0, although a 4.6 occurred in 1973 and magnitude four events increased thereafter. Even with increasing injection rates over time, the rate of magnitude 3 earthquakes has remained relatively unchanged since the 1980s, although the absolute number of earthquakes has increased significantly. A magnitude 4.5 earthquake struck near the Geysers on January 12, 2014 and a magnitude 5.0 on December 14, 2016. A magnitude 3.8 earthquake, with a hypocenter 600 meters directly under the field, struck in the early hours of March 3, 2022. Despite the increases in the number of earthquakes and the fears of local residents, it is unlikely that a large earthquake will occur at the Geysers since there is no fault or fracture nearby.
Geochemistry
In 2005, abatement equipment was installed at two of the Geysers plants to reduce the amount of mercury released by the waste vapor even though the amount released was below the legal limit for such releases. The Geysers Air Monitoring Programs (GAMP) has shown limited releases of arsenic, but again below a significant level.
Production
Power plants at the Geysers are of the dry steam power plant type, where the steam directly powers the generator. In general, the Geysers has of active installed capacity with an average production factor of 63% (955 MW).
Of nearly two dozen active plants in the Geysers in 2014, Calpine Corporation
Calpine Corporation is the largest generator of electricity from natural gas and geothermal power, geothermal resources in the United States, with operations in competitive power markets.
A Fortune 500 company based in Houston, Texas, the compan ...
operated 19 plants in 2004 but only 15 in 2013. Two other plants are owned jointly by the Northern California Power Agency and the City of Santa Clara In July 2009, AltaRock Energy AltaRock Energy Inc. is a privately held corporation that focuses on the development of geothermal energy resources and enhanced geothermal systems (EGS). It is headquartered in Seattle, Washington and has a technology development office in Sausal ...
planned to drill more than down to create an "enhanced geothermal" project which was abandoned when federal agencies asked for review. Another plant was under development by Ram Power Corporation, formerly Western Geopower, in 2010, but after Ram Power lost both its CEO and CFO in 2013, it was seeking a buyer for its Geysers property.
Geology
The Geysers is located on the northeast limb of the Mayacamas anticline
In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...
, bounded by the Collayomi Fault on the northeast and the Mercuryville Fault on the southwest. The central and eastern Franciscan belts form the core of this anticline. Within this belt is a rock unit forming the reservoir rock, consisting of a sheared and fractured graywacke. A large Bouguer Gravity In geodesy and geophysics, the Bouguer anomaly (named after Pierre Bouguer) is a gravity anomaly, corrected for the height at which it is measured and the attraction of terrain. The height correction alone gives a free-air gravity anomaly.
Defini ...
anomaly combined with slower seismic velocities, located below the Clear Lake Volcanic Field
The Clear Lake Volcanic Field is a volcanic field beside Clear Lake in California's northern Coast Ranges. The site of late-Pliocene to early Holocene activity, the volcanic field consists of lava domes, cinder cones, and maars with eruptive p ...
, suggests a magma body is heating the geothermal area.
See also
* List of geothermal power stations in the United States
Geothermal power stations in the United States are located exclusively within the Western United States where geothermal energy potential is highest. The highest concentrations are located in the Mayacamas Mountains and Imperial Valley of Cali ...
* List of power stations in California
This is a list of power stations in the U.S. state of California that are used for utility-scale electricity generation. This includes baseload, peaking, and energy storage power stations, but does not include large backup generators. , Calif ...
References
External links
*
*
*
*
{{DEFAULTSORT:Geysers, The
Hot springs of California
Mayacamas Mountains
Geothermal power stations in California
Bodies of water of Lake County, California
Bodies of water of Mendocino County, California
Bodies of water of Sonoma County, California
California Coast Ranges
Geology of Mendocino County, California
Geology of Sonoma County, California
Companies based in Lake County, California
Energy infrastructure completed in 1960
Buildings and structures in Sonoma County, California
Geography of the San Francisco Bay Area
Energy in the San Francisco Bay Area
1921 establishments in California