The Moss Landing Power Plant is a
natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
powered
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
generation plant located in
Moss Landing, California
Moss Landing, formerly Moss, is an unincorporated community and census-designated place (CDP) in Monterey County, California, United States. It is located north-northeast of Monterey, at an elevation of . It is on the shore of Monterey Bay, at the ...
, United States, at the midpoint of
Monterey Bay
Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area and its major city at the south of the bay, San Jose. San Francisco itself is further north along the coast, by a ...
. Its large
stack
Stack may refer to:
Places
* Stack Island, an island game reserve in Bass Strait, south-eastern Australia, in Tasmania’s Hunter Island Group
* Blue Stack Mountains, in Co. Donegal, Ireland
People
* Stack (surname) (including a list of people ...
s are landmarks, visible throughout the
Monterey Bay Area
Monterey (; es, Monterrey; Ohlone: ) is a city located in Monterey County on the southern edge of Monterey Bay on the U.S. state of California's Central Coast. Founded on June 3, 1770, it functioned as the capital of Alta California under both ...
. The plant is owned and operated by
Houston
Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 in ...
-based
Dynegy
Dynegy Inc. is an electric company based in Houston, Texas, in the United States. It owns and operates a number of power stations in the U.S., all of which are natural gas-fueled or coal-fueled. Dynegy was acquired by Vistra Corp on April 9, 20 ...
and currently has a generation capacity of 1020
MW (net) from its two
combined cycle
A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...
generation units. It was once the largest power plant in the state of California, with a generation capacity of 2560 MW, before its two large supercritical steam units were retired in 2016.
It is to be the site of a new
battery storage power station
A battery storage power station is a type of energy storage power station that uses a group of batteries to store electrical energy. Battery storage is the fastest responding dispatchable source of power on electric grids, and it is used to sta ...
for
grid battery storage of over 567 MW / 2,270 MWh of power, potentially the world's largest when completed.
History
In 1949,
Pacific Gas & 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 ...
(PG&E) began construction on the Moss Landing Power Plant. Five natural gas and oil powered steam units were built during the 1950s. Commercial generation started in 1950 with a capacity of 613 MW.
In 1964, the construction of two additional units began (6 and 7), with two new stacks. These two units had a capacity of 750 MW each for a total of 1500 MW, with tall boilers. They employed a newer technology using
supercritical steam at .
In 1995, the original five units were retired, and in 1997 PG&E let the permits lapse for these units.
As part of the Deregulation of Utilities in California, PG&E sold the plant to
Duke Energy
Duke Energy Corporation is an American electric power and natural gas holding company headquartered in Charlotte, North Carolina.
Overview
Based in Charlotte, North Carolina, Duke Energy owns 58,200 megawatts of base-load and peak generation in ...
(DENA) in 1998. To comply with more restrictive pollution regulations, units 6 and 7 were upgraded in 1998 with a
selective catalytic reduction
Selective catalytic reduction (SCR) is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen (), and water (). A reductant, typically anhydrous ammonia (), aqueous ammonia (), or a urea () s ...
unit and digital control systems.
Starting in 2000, the eight stacks and 19 fuel oil storage tanks were removed, and two new units were built on the former site. The new units 1 and 2 were brought online in 2002. They are
combined cycle
A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...
units, 50% more efficient than the other units, because they use two turbines: first, a pair of 170 MW gas turbines, then a 190 MW steam turbine, for a total of 530 MW each. When completed in 2002, the plant was the largest power plant in California by capacity, at 2560 MW.
In 2006, having invested over half a billion dollars in upgraded capacity, efficiency and emission control, Duke Energy sold the plant to LS Power Equity Partners.
Dynegy
Dynegy Inc. is an electric company based in Houston, Texas, in the United States. It owns and operates a number of power stations in the U.S., all of which are natural gas-fueled or coal-fueled. Dynegy was acquired by Vistra Corp on April 9, 20 ...
then purchased the plant in April 2007 along with other assets of LS partners.
In 2015, a transmission tower collapsed at the power plant, causing a major Monterey County area power outage.
On December 31, 2016, Dynegy retired supercritical steam units 6 and 7 as they were no longer economically competitive. However, Dynegy continues to maintain the permit on these units.
In February 2017, independent power producer Dynegy, Inc. announced that it may close the gas plant, due to market conditions resulting from a glut of wholesale electricity capacity in California making it difficult to operate profitably.
By 2018, California had 7,000 MW of surplus generating capacity, but a similar amount (mostly ocean cooled) would be retired by 2021. The glut in electricity capacity is partially a result of policies which guarantee utilities like PG&E (a regulated monopoly) a return on investment for building new power plants, even when they are not needed. Independent power producers like Dynegy, on the other hand, do not have a guaranteed return on their investment.
Power production has dropped considerably, reducing taxes paid to
Monterey County
Monterey County ( ), officially the County of Monterey, is a county located on the Pacific coast in the U.S. state of California. As of the 2020 census, its population was 439,035. The county's largest city and county seat is Salinas.
Montere ...
.
[ ]
Grid connection
The plant has power lines that connect it to
Path 15
Path 15 is an portion of the north–south power transmission corridor in California, U.S. It forms a part of the Pacific AC Intertie and the California-Oregon Transmission Project. Path 15 is part of The Western Electricity Coordinating Coun ...
, and interconnections like
Path 26
Path 26 is a set of three Southern California Edison (SCE) 500 kV power lines, located primarily in Los Angeles County, and extending into Kern and Ventura counties, all in California. Path 26 is part of the Western Electricity Coordinating Coun ...
and
Path 66
California Oregon Intertie (COI), identified as Path 66 by Western Electricity Coordinating Council (WECC), is a corridor of three roughly parallel 500 kV alternating current power lines connecting the electric grids of Oregon and California. Th ...
that allow power to flow to far-away regions. The plant is also connected to local loads and the
San Jose region by transmission lines.
Gas units
Both the supercritical units and the combined cycle units use once-through cooling. The supercritical units have a cooling requirement of per minute, and the combined cycle units a requirement of .
Supercritical Steam Units 6 and 7
Units 6 and 7 used
supercritical steam. These units were retired at the end of 2016. At the end of their life, units 6 and 7 were typically operated as peaking units when demand for electricity was highest. In 2016, the last year of operation, they only operated approximately 3% of the time.
The generation process for units 6 and 7 starts with natural gas injected at one end of the boiler to be burned. Primary water is injected at the other end of the boiler to receive the heat produced. The gas simply comes from a natural gas pipeline, and combustion products go up the stack and into the atmosphere. Water has a much more complicated path, and consists of two distinct systems: coolant water and primary (steam-generating) water. Cooling water is pumped out of the Monterey Bay or the nearby
Elkhorn Slough
Elkhorn Slough is a tidal slough and estuary on Monterey Bay in Monterey County, California. It is California's second largest estuary and the United States' first estuarine sanctuary. The community of Moss Landing and the Moss Landing Power Plan ...
. Then it is purified, used to cool down the water coming from the turbines, and discharged into the ocean. Steam for the turbines is created from the primary water flow, which is preheated before entering the boiler. From the boiler, the superheated steam is directed into a first
turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating e ...
working at high pressure, then into a low pressure turbine. The turbines drive the generators.
Combined Cycle Units 1 and 2
Combustion products drive the gas turbines directly. First, air is drawn from the air intake to the compressor (driven by the turbine axle), then it is burned with natural gas in the combustion chamber. The hot combustion gasses then go through the actual turbine (driving the axle). From a thermodynamic standpoint, this is the standard
Brayton cycle
The Brayton cycle is a thermodynamic cycle that describes the operation of certain heat engines that have air or some other gas as their working fluid. The original Brayton engines used a piston compressor and piston expander, but modern gas tur ...
. Because the gas turbine does not transfer energy from the combustion process to the turbine via steam, it avoids the cost, energy loss and environmental impact of the primary water cycle.
At the output of the gas turbines, some of the remaining energy (heat) in the exhaust gas is recovered through a heat exchanger and transferred to water that feeds a steam turbine, similar to units 6 and 7.
On a smaller scale than the supercritical units, units 1 and 2 are also more flexible, with a start-up time of only an hour, against 24 hours for units 6 and 7.
Battery storage
Utilities in California are required by a 2013 law to provide significant battery storage by 2024.
Vistra 500 kV
On June 29, 2018,
Vistra Energy, which merged with Dynegy on April 9, 2018, announced that it will develop a 300 MW / 1,200 MWh energy storage system to be located at
Moss Landing
Moss Landing, formerly Moss, is an unincorporated community and census-designated place (CDP) in Monterey County, California, United States. It is located north-northeast of Monterey, at an elevation of . It is on the shore of Monterey Bay, at the ...
, using the existing turbine building and existing interconnection from units 6 and 7, connecting to the 500 kV grid.
Vistra Energy expects the energy storage system to begin commercial operation by the end of 2020, pending receipt of approval from
California Public Utilities Commission
The California Public Utilities Commission (CPUC or PUC) is a regulatory agency that regulates privately owned public utilities in the state of California, including electric power, telecommunications, natural gas and water companies. In additi ...
(CPUC). This would be the largest lithium-ion battery energy storage system in the world. The project began construction in December 2019, and Phase 1 began operating at the end of 2020. It is made of LG JH4 cells in TR1300 racks in two storeys in the old turbine hall. A further 100 MW (Phase 2) was completed in August, bringing capacity to 400 MW.
In September 2021, Phase 1 was shut down after a high temperature event caused by a leak in a liquid cooling hose, while Phase 2 kept operating. In February 2022, Phase 1 remained offline while Phase 2 also went offline after a sprinkler event. Most of the facility was back in operation as of July 2022.
An expansion to 1,500 MW/6,000 MWh (also connecting to the 500 kV grid) was approved in August 2020, but not decided.
Elkhorn 115 kV
Utilities in California are required by a 2013 law to provide significant battery storage by 2024.
Pacific Gas & 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 ...
(PG&E) asked the CPUC to approve four energy storage projects located at Moss Landing including another large lithium-ion battery storage system of 182.5 MW / 730 MWh ("Elkhorn") to be provided by
Tesla and owned and operated by PG&E, connecting to the regional 115 kV grid.
The project is designed to improve energy reliability and to allow for more renewable energy sources to be used at the Moss Landing site
by increasing electricity storage available in California. The project also aims to save costs by reducing PG&E's reliance on
peaker power plants that come online during periods of increased demand.
On July 3, 2019, in accordance with the
California Environmental Quality Act
The California Environmental Quality Act (CEQA) is a California statute passed in 1970 and signed in to law by then-Governor Ronald Reagan, shortly after the United States federal government passed the National Environmental Policy Act (NEPA), t ...
, the
County of Monterey Resource Management Agency published a Mitigated Negative Declaration, detailing actions that must be taken to mitigate potential environmental impacts of the project.
The report concluded that the project would have a "Less than Significant Impact" on the environment, assuming the correct mitigating actions were taken.
Specifically, it was found that mitigating actions were required to minimize the environmental impact of the project on "biological resources" such as wildlife habitat, and on "cultural resources", especially culturally-significant archaeological sites at the proposed location of the Megapack deployment.
The project was subsequently opened to public submissions on its environmental impact.
California Unions for Reliable Energy argued that the County of Monterey failed to meet the standards of the
California Environmental Quality Act
The California Environmental Quality Act (CEQA) is a California statute passed in 1970 and signed in to law by then-Governor Ronald Reagan, shortly after the United States federal government passed the National Environmental Policy Act (NEPA), t ...
when performing its environmental assessment.
This same union group, with the same legal representation, used similar arguments against the California Flats solar project in order for organized labor to get concessions from the developer.
In February 2020, the Monterey County Planning Commission unanimously approved the project, which was initially scheduled to start construction in late March
[ and be complete by 2021. However, the ]COVID-19 pandemic in California
Ten of the first twenty confirmed COVID-19 cases in the United States occurred in California, the first of which was confirmed on January 26, 2020. All of the early confirmed cases were persons who had recently travelled to China, as testing wa ...
and subsequent stay-at-home order forced the project to be delayed. Construction began in July 2020, commissioned in April 2022, and inaugurated in June 2022.
See also
*Energy in California
Energy in California is a major area of the economy of California. California is the state with the largest population and the largest economy in the United States. It is second in energy consumption after Texas. , per capita consumption was t ...
*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. , Cali ...
*List of energy storage projects
This is a list of energy storage power plants worldwide, other than pumped hydro storage.
Many individual energy storage plants augment electrical grids by capturing excess electrical energy during periods of low demand and storing it in oth ...
References
{{Generating stations in California, state=autocollapse
Natural gas-fired power stations in California
Buildings and structures in Monterey County, California
Monterey Bay
Energy infrastructure completed in 1949
1949 establishments in California
Vistra Corp