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A long awaited natural gas conversion for the TransAlta power plant in Centralia is now in the works as the plant's last coal-fired generation unit prepares to go offline this month as part of a longstanding agreement with the state.
TransAlta announced Tuesday morning that the Lewis County-based coal-fired power plant will convert one of its two boilers to a natural gas-fueled generation system.
At the same time, the Canadian-based power generation company announced a long-term deal to sell the power generated by the facility to Puget Sound Energy (PSE) through the end of December 2044.
The burner that will be converted is currently scheduled to be shut down and cease burning coal at the end of the month as the last deadline included in a piece of 2011 legislation, which in part orchestrated the shutdown of the state's only remaining coal-fired power plant.
The company expects the converted facility to produce 700 megawatts of power each year. The company added that it is not considering any work to convert the facility’s unit 1 coal-fired generation unit in the same way. That unit was decommissioned at the end of 2020, also in accordance with 2011 legislation mandating the closure.
“Our Centralia facility has a long history of providing reliable and affordable power in the Pacific Northwest region. We are pleased to extend the useful life of this asset and support the ongoing reliability needs of PSE and, by extension, its customers” TransAlta President and Chief Executive Officer John Kousinioris said in the announcement.
The company predicts that it will cost $600 million to convert the existing facility. It hopes to begin commercial operation of the converted facility by the end of 2028. The company says it expects to publish a final investment decision at the end of 2027 after both TransAlta and Puget Sound Energy receive all required approvals and permitting from the relevant regulatory agencies.
TransAlta staff said in response to questions asked by The Chronicle that its plans follow all existing regulatory rules, hinting that it expects its permits to be approved.
“The project is consistent with all federal, state and local laws, and no new legislation is required for it to proceed,” the company said in a statement.
According to the TransAlta team, the company will soon submit permitting applications and will begin working through the regulatory process next year. At the same time, the facility will start early engineering and planned power outage work that will be necessary for the conversion.
The primary construction work, selection of a contractor to do the conversion and any other major decisions are expected to be announced after the facility has secured the necessary permits and regulatory approval. The company expects to begin major construction at the beginning of 2027 after the necessary approvals.
The work to convert the facility and all of the changes are expected to stay within the site's current footprint. Construction will start with retiring the old “coal-handling systems,” replacing burners for natural gas combustion, installing a new water-bath heater and boiler, and replacing the existing cooling towers.
The company says it expects to continue using most of the major infrastructure already in the facility. The main boiler, turbines and electrical transmission systems used previously will continue to be used. The facility will need to install a new 1,500-foot underground natural gas pipeline to connect the facility to an existing natural gas pipeline.
Construction and conversion work for the facility will require all hands on deck. Conversion is expected to create up to 700 temporary jobs at the peak of the work. Once finished and operating as normal, the facility will require roughly 40 people to operate day-to-day.
That represents a continued reduction in workforce at the facility for a site that once employed hundreds of people and laid off more than 60 employees when its first boiler went offline in 2020.
In the past, the company has raised concerns over the economic side of converting to natural gas, painting it as uncertain. According to TransAlta staff, the conversion is made possible in part by the agreement with PSE and in part because the reuse of parts in the current facility will cut down on costs, especially when compared with the cost of constructing a new facility.
“The Tolling Agreement provides long-term contracted cash flow through 2044,” reads a statement from the company. “By utilizing and repurposing existing infrastructure, the conversion is a cost-effective, lower-emission solution compared to building a new facility and supports regional grid reliability.”
However, the site remains uncertain until TransAlta and PSE receive the necessary approval from regulatory agencies. Its future beyond the agreement with PSE’s end date in 2044 means it is especially uncertain as a long-term energy production facility.
Local stakeholders are observing the development with cautious optimism.
Lewis County Public Utility District (PUD) General Manager David Plotz said he was excited to see the progress being made, but added the PUD would wait to make plans based on the conversion until permitting and other regulatory hurdles have been overcome.
Washington state Sen. John Braun, R-Centralia, has seemingly expected the news. He hinted at the natural gas conversion in early November during a legislative forum in Chehalis.
“The reality is you can't get from where we are today to where we want to be in the future with clean energy without somewhere between six and 12 gas plants,” Braun said during the November forum. “One of them is going to be at the TransAlta site, and they’re being really quiet about it, but there are significant players already at work on that.”
During the same meeting, Braun also signaled his belief that the plant was unlikely to be an intergenerational solution to energy in the area. Instead, he suggested the plant would be a good candidate for a small nuclear reactor, adding that natural gas could be a stop gap between coal and nuclear energy.
“The state, Energy Northwest and Puget Sound Energy has invested heavily in building a small nuclear reactor at the Hanford site but for the Tri-Cities,” Braun said. “We need to do the work to rally support for that based on new, current technology, and get that at the TransAlta site. We do that, we do that in the next couple years, so that we're all ready, we're ready to build right after they build in Hanford. That's the long-term solution.”
