The Centralia Power Plant, known also as the Centralia Coal Plant, Centralia Steam Plant, or Centralia Steam-Electric Plant, is a coal-fired power plant supplemented with a natural gas power plant known as the Big Hanaford Power Plant. The combined coal and natural gas facility is located east of Centralia in the Hanaford Valley of Lewis County, Washington.
The plant, owned by TransAlta, is situated on and at its peak generated enough energy to power Los Angeles. The two-boiler, fossil fuel power station was constructed beginning in 1968. Both boilers were fully operational by 1972. The Centralia Coal Mine was opened in 1970 to provide the fuel source for the plant. The Skookumchuck Dam was built to provide water as a cooling source. The natural gas facility opened in 2002.
The coal mine was closed in 2006 due to operational costs. Following in 2011, a Washington state law was signed to permanently shutter the steam plant. The first boiler unit was shut down in 2020. The Centralia Power Plant, the last commercial energy production facility to be powered by coal in the state, was expected to close as a coal powered plant by the end of 2025 but was ordered to remain operational through mid-June 2026 by the Department of Energy.
TransAlta announced in December 2025 that the second coal boiler of the plant was to be converted into a natural gas-burning unit. Planned to be running by 2028, the updated unit is contractually obligated to remain operational through 2044.
History Construction and beginning operations In December 1951, an estimated of bituminous coal was discovered in Lewis County near Centralia by the United States Department of the Interior. The Centralia Coal Mine began as part of the construction of the steam-electric power plant, in Hanaford Valley, which was first made public in January 1967 in the local newspaper, The Chronicle. The facility was considered to be more cost-effective than a nuclear power plant and a state representative declared that it was "about time" that the coal fields in Lewis County were to be utilized. Other local leaders, including Governor Daniel J. Evans, welcomed the news, agreeing on resource usage while also focusing on economic prosperity for the region.
The construction of a one-gigawatt, steam-generated plant, to be built by Pacific Power & Light Company of Portland and Spokane-based Washington Water Power Company, was officially announced in May 1967. The proposal, estimated at first to cost $140 million, also disclosed the construction of the Skookumchuck Dam, the reservoir to be used for cooling purposes at the plant. The first efforts on the project began with road construction to the site the prior month.
Under oversight of Bechtel Corporation, construction of a first boiler unit began on June 13, 1968. A ceremonial groundbreaking was held on August 23, 1968, attended by Governor Evans, other state officials, and a crowd of 500 people. Governor Evans pushed a button that activated the "first" pouring of concrete at the site. The cost of the plant was revised to $206 million with a 700-megawatt capacity of the first unit; a second unit was to be built later when additional was to be required. The design and construction of the new plant were by Stone & Webster and ABB Environmental Systems.
In anticipation of the electrical facility, Bonneville Power Administration began efforts by August 1968 to upgrade the electrical grid within Centralia and Chehalis, Washington. Announcements at the time also reported that the plant was to produce up to 1.4 gigawatts once both units were operational. An untitled, multi-part documentary was filmed during the early construction phases of the mine and plant. Also focusing on the concerns of environmental impacts, early screenings in 1970 were hosted in Centralia; reviews were considered positive and ecological concerns abated by the positive tone of the movie.
The first turbine began operations on August 6, 1971, powered by steam generated by burning oil. Coal was first used in the furnace on August 14 and a dedication ceremony was held the following month. In honor of the steam plant's opening, and the Centralia Coal Mine's connection to the project, the Centralia newspaper, The Daily Chronicle, published a 52-page special known as the "Steam Plant Dedication Edition" on September 24, 1971.
The second boiler was officially lit for inspection in late-August 1972, and the entire plant was considered effectively complete and on schedule, with operations at full capacity, by early September. Approximately 1,200 people were employed during the four-year construction phase which was built at a finalized cost of $230 million.
The construction of the plant was reported to provide Centralia, Chehalis, and surrounding communities with noticeable increases to the local economy, particularly in mortgage lending and multiple infrastructure improvement projects despite an era of economic stagflation. Banks reported savings deposit increases during the construction including one bank that reported a jump of $1.5 million in 1970. Sales receipts were also reported as amplified, with businesses reporting increases between 18% and 25% annually.
21st century and closure By 2000, the plant was noted for a more than 5-year stretch without a "time-loss" accident; total employees numbered were listed at approximately 120. Including employees at the Centralia Coal Mine, jobs via TransAlta in Lewis County totaled 680 people. Employment numbers at the plant were listed at 225 in 2006. The plant, at its peak, was considered the largest employer in Lewis County.
TransAlta constructed the 248 MW, natural-gas-powered Big Hanaford power plant on the grounds of the coal plant. Completed on time and on budget, the $215-million plant went online on August 12, 2002.
In 2006, the adjacent Centralia Coal Mine was closed due to operating costs, eliminating approximately 600 jobs. In 2011, a bill signed in 2011 by governor Christine Gregoire, the TransAlta Energy Transition Bill (TAETB) also known as Senate Bill 5769, authored in an agreement to permanently close the Centralia Power Plant in 2025. A coal boiler was shut down in 2020 as part of beginning phase of the closure.
Multi-million-dollar funds, to be used for clean energy investments and programs for the Centralia community and throughout the state, were required as a part of the TAETB bill. The bill required a $55 million "community transition fund" set aside by TransAlta. An additional fund up to $30 million was initiated to lower nitrogen oxide levels beginning in 2013; the plant has already begun an upgrade to reduce mercury emissions beginning in 2012. TransAlta created a $20 million fund for training and educational work programs for remaining employees of the plant. Part of a larger Centralia Coal Transition Grants initiative, other grants include millions for energy efficiency and technology for nearby communities and schools. The land at the site has slowly been reclaimed for public and commercial use, including the planting of trees and maintaining wetland areas.
By 2025, the plant was the last commercial coal-fired power plant remaining in the state. The last load of coal burned at the Centralia Power Plant was recorded to have been in mid-December 2025.
Conversion to natural gas plant In December 2025, TransAlta announced that a 16-year contractual agreement was signed with Puget Sound Energy to convert the second coal boiler into a natural gas burning unit. Providing up to 700 megawatts, the conversion was planned to be functional by 2028 and is to remain operational through 2044. The continuing use of fossil-fuel burning for power at the plant was deemed necessary to avoid brownouts and blackouts until planned renewable energy projects in the state could be completed. Cost estimates are reported to be approximately $600 million and the project is expected to begin in early 2027. At the time of the announcement, the project lacked full approval and subsequent permits from regulatory agencies.
In late-December, TransAlta began efforts for environmental cleanup of the site and surrounding area, including mitigation of air, sediment and soil, and groundwater contamination. The initiative was begun under an order by the Washington State Department of Ecology (WSDOE); the agency will have oversight over the project.
In July 2026, TransAlta was officially authorized by the WSDOE to begin the transition of the site for use as a peaker plant. Under the agreement, TransAlta is required to spend millions of dollars per year for renewable energy projects in Lewis and Thurston counties; the amount fluctuates depending on the annual emissions of the Centralia plant. The contract also stipulates that the natural gas facility will close operations by 2044 in order to comply with a statewide mandate for the cessation of the burning of fossil fuels for energy production.
In opposition to the gas generating facility, a group known as Washington Conservation Action noted that the plant could possibly become a larger polluter than the Cherry Point Refinery. Additionally, costs associated with the efforts were higher than initially planned as well as unusually large compared to other similar conversion operations. The group also cited permits sought by TransAlta in regards to planned capacity of up to 59%, beyond the normal 5 to 15% range for a peaker plant.
Federal orders to maintain coal-burning operations, 2025-2026 In mid-December 2025, the United States Department of Energy (DOE) announced through an emergency order under the Federal Power Act that TransAlta was to “take all measures necessary” to provide “affordable, reliable and secure electricity” by the continued operations of the remaining coal-burning unit of the Centralia Power Plant until March 16, 2026. The BPA was required to "facilitate transmission" and the plant was no longer allowed to be referred to as a “capacity resource", otherwise known as an energy facility that can increase or decrease output on demand.
Other coal-burning power plants in the country, also planned to be deactivated, had previously been given similar, temporary orders. The DOE cited two executive orders that stated concerns over national security issues and energy emergencies. Additionally, the DOE mentioned the coal plant's retirement could potentially lead to rolling blackouts during extreme weather events in the state. Also noted by the agency was a lack of renewable energy sourcing coupled with expected electricity demand driven by data centers and industrial expansion.