Frequently asked questions

Converting Centralia Unit 2 allows TransAlta to continue using existing generation, transmission and site infrastructure while minimizing new land disturbance. The project will be developed within the existing industrial footprint, enabling a faster and more cost-effective conversion compared to a new facility, while continuing to provide reliable electricity to the region.

Compared with historical coal operations, the project substantially reduces greenhouse gas emissions while providing reliable dispatchable electricity. Because the coal units closed a combined 25 years earlier than originally planned, the overall transition has already avoided tens of millions of metric tons of CO₂ emissions. Even after accounting for operation of the converted unit, the Centralia transition remains one of Washington’s largest greenhouse gas reduction efforts: the coal-to-gas (CTG) project will result in a net reduction of approximately 940,571 MTCO2e from Unit 2 alone, and a reduction of 66,520,589 MTCO2e when the early retirement of Unit 1 is included.

Renewable energy and battery storage are essential components of Washington's clean energy future. However, current technologies cannot always provide the firm, dispatchable electricity needed during extended periods of low wind, low solar generation, extreme weather events or other system constraints.

Recent Pacific Northwest reliability studies show that low-hydro years greatly exacerbate both the likelihood and duration of these potential grid blackout periods. The converted facility is intended to operate as a reliability resource that supports the power system, while helping address identified resource adequacy needs in the region.

Regional electricity demand continues to grow while multiple studies have identified potential capacity shortfalls beginning as early as 2028. Regional forecasts identify a need for approximately 5,855 MW of additional summer capacity and 4,174 MW of additional winter capacity by 2028, increasing to more than 13,000 MW by 2035. The converted facility is expected to provide up to 723 MW of firm, dispatchable generating capacity and critical grid-support services that help maintain reliability when electricity demand is high or renewable generation is unavailable.

Under the terms of the agreement, Puget Sound Energy will control dispatch of the facility. The converted unit will not operate more than 59 per cent of the time on an annual basis and is expected to be used primarily to support system reliability and resource adequacy needs when required.

While the actual use of the unit is anticipated to be much less than 59% of the time on an annual basis for most years, this higher permitted annual capacity limit allows for flexibility to address unpredictable grid needs over the project’s ~16-year lifespan.

The project supports the clean energy transition while maintaining the reliability needed to support a growing electricity system and increased levels of renewable energy. The conversion significantly reduces emissions compared to coal operations, supports integration of renewable resources, continues to use the existing facility footprint and infrastructure and will comply with applicable Washington climate and environmental requirements, including the Climate Commitment Act.

Compared to historical coal operations, the conversion is expected to significantly reduce emissions of most major pollutants. At the proposed operating profile, GhG emissions are projected to decrease by approximately 51 per cent, while sulphur dioxide emissions are projected to decrease by approximately 99 per cent. Significant reductions are also expected in nitrogen oxides, particulate matter, carbon monoxide and lead emissions. The project includes low NOx burners, flue gas recirculation and combustion optimization systems to support compliance with applicable air quality requirements.

The project is being developed within the existing Centralia facility footprint and uses existing infrastructure wherever possible. Where possible, the project has been designed to avoid impacts and minimize disturbance during construction and operation.

The project is not expected to increase water use or wastewater discharge during operations. Existing water rights, water management systems and permits will continue to be used. Water previously required for coal-related flue gas desulphurization processes will no longer be necessary following the conversion. Existing stormwater and wastewater management systems will continue to operate under applicable permits and regulatory requirements.

The project is located primarily within the existing Centralia facility footprint and developed industrial areas. Environmental studies completed as part of the SEPA review identified limited impacts to habitat, wetlands and sensitive species. Construction and operations will incorporate required avoidance, mitigation and monitoring measures and no wetland vegetation is expected to be cleared during construction or operations.

Temporary noise associated with construction activities is anticipated and will be managed in accordance with applicable requirements. Long-term operational noise levels are expected to be lower than historical coal operations due to the removal of coal handling equipment, rail activity and associated infrastructure. New equipment associated with the conversion is expected to be substantially quieter than much of the equipment it replaces.

TransAlta remains committed to its employees and the Lewis County community. The project is expected to support approximately 700 construction jobs and continue supporting more than 40 permanent positions at the facility.

The conversion would also extend the operating life of Centralia Unit 2 through 2044, supporting continued economic activity and employment at the site.

Through the 2011 Centralia Transition Agreement, TransAlta committed more than $55 million to support workers, education, energy efficiency and economic diversification initiatives in Lewis County. Reclamation of former mining lands will continue, with more than 3,200 acres restored and more than 1.7 million trees planted since 1991.

Safety remains TransAlta's highest priority. Existing emergency response programs and procedures will be maintained and updated as required. Construction and operations will comply with applicable environmental, safety and emergency management requirements and TransAlta will continue coordinating with local authorities and emergency responders.

The project requires several local and state permits and approvals, including an Air Discharge Permit from the Southwest Clean Air Agency, updates to existing water and stormwater permits administered by the Washington Department of Ecology, and various Lewis County construction, land-use and development approvals. The project is currently progressing through established regulatory review and permitting processes.

TransAlta will fund construction of the conversion project. Under a long-term agreement, Puget Sound Energy will make capacity payments to TransAlta in exchange for access to the facility's generating capacity and reliability benefits.

Construction is expected to begin following receipt of required permits and approvals. Commercial operation of the converted facility is anticipated in the second half of 2028.