TransAlta Completes Second Coal-to-Gas Conversion

A Canada-based energy company has completed the second of three planned coal-to-gas conversions at its thermal power plants in Alberta.

TransAlta Corp. on July 19 said the conversion of the 395-MW Unit 2 at the Keephills plant near Wabamun, about 45 miles west of Edmonton, continues the company’s transition away from coal-fired power generation. TransAlta in February completed the switch from coal to natural gas at the 401-MW Unit 6 at the Sundance plant in Sundance, Alberta, on the southwest shore of Wabamun Lake. The company expects to finish its conversion of the 463-MW Unit 3 at Keephills later this year.

The Keephills plant is about 15 miles southeast of the Sundance facility.

TransAlta’s energy diversification was the subject of a POWER feature in 2016.

‘Significant Milestone’

“The full conversion of Keephills Unit 2 [KH2] from thermal coal to natural gas is another significant milestone for TransAlta as it transitions off coal. We are pleased to have completed another step in our plan toward 100% clean electricity by end of 2021 in Alberta,” said John Kousinioris, president and CEO of TransAlta, in a statement. “Converting to natural gas from coal maintains our current generation capacity and reduces our CO2 emissions by more than half from approximately 1.04 tonnes CO2e per MWh to approximately 0.51 tonnes CO2e per MWh in 2021. This not only highlights TransAlta’s commitment to meet Alberta’s need for safe, reliable and low-cost electricity but also our commitment to meet our sustainability goals focused on clean electricity generation.”

The Keephills thermal power station in Alberta, Canada, is part of TransAlta’s plan to convert its coal-fired power generation units to burn natural gas. Courtesy: TransAlta

TransAlta said it has committed more than $96 million to the KH2 conversion project, including $31.5 million for the switch from coal to gas, and an additional $64.7 million for system upgrades, gas infrastructure, and maintenance projects. The company on Tuesday said about 800 jobs were created to complete the unit’s conversion.

TransAlta has set a target of reducing its greenhouse gas (GHG) emissions by 60%, or 19.7 million tonnes, annually by 2030 compared to 2015 levels. The company has said it wants to be carbon-neutral by 2050. The company said it already has reduced its GHG emissions by 25 million tonnes annually, which represents about 8% of Canada’s total goal of cutting GHG emissions by as much as 329 million tonnes from 2005 levels by 2030. TransAlta is diversifying its generation portfolio by adding wind and hydropower assets, along with reducing its dependence on coal-fired generation.

The company earlier this year announced it had achieved commercial operation of WindCharger, 10-MW battery storage project that is Alberta’s first utility-scale energy storage facility.

Applications Filed in 2018

TransAlta first filed amendment applications with the Alberta Utilities Commission (AUC) and Alberta Environment and Parks (AEP) in summer 2018 for the conversions at Sundance and Keephills. The AEP issued its final approvals for the changes in July 2019.

TransAlta in mid-2019 said it had completed construction of the Pioneer Pipeline, which supplies natural gas for Keephills and Sundance. The company, together with partner Tidewater Midstream & Infrastructure, on June 30 announced it had sold the pipeline for $255 million to Calgary, Alberta-based ATCO Gas and Pipelines Ltd.

The Sundance power plant at its peak had more than 2.1-GW of generation capacity from its six units. TransAlta permanently retired Units 1 and 2—the two oldest and smallest units, each with 280 MW of capacity—in 2018.  Units 3 and 5 at the plant were mothballed in April of that year. Unit 3 had 368 MW of coal-fired capacity; Unit 5 had 406 MW of coal-fired capacity. Unit 5 is now part of a repowering project expected to give the unit 730 MW of gas-fired capacity as early as the fourth quarter of 2023.

Units 4 at Sundance was commissioned in 1977, and co-fired coal and natural gas, with 406 MW of capacity. TransAlta plans to discontinue burning coal in the unit at the start of next year, leaving a gas-fired unit with 70 MW of capacity.

TransAlta also is continuing with plans to repower Unit 1 at Keephills. As with Unit 5 at Sundance, existing steam turbines will be used, along with new combustion turbine generators and heat recovery steam generators. The repowered Unit 1 at Keephills is expected to generate about 640 MW of power, according to the company, which in a March earnings report said the Unit 1 repowering could be online “in the 2026 to 2030 timeframe.”

Darrell Proctor is a senior associate editor for POWER (@POWERmagazine).

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