The conversion of Keephills Unit 3 from coal to natural gas ends the last of three planned conversions at the power producer’s facilities inAlberta. KH3 will maintain its original generating capacity of 463 MW, the company said. TransAlta said the KH3 job cost C$29 million ($22.83 million), plus another C$48 million ($37.79 million) for gas infrastructure and maintenance projects. Since 2019, the company said it has spent C$295 million ($232.27 million) on coal-to-gas conversion projects at its Keephills, Sundance and Sheerness facilities.
As part of the conversion, the pulverized coal burners were replaced with gas burners, but the existing boiler and steam turbine equipment remained largely in place. The relatively low-cost conversion was completed within a few months, and yielded no marked improvements either in heat rate or efficiency.
Keephills entered service in 2011 at a cost of C$1.98 billion ($1.56 billion) and included a supercritical boiler and turbine, supplied by Hitachi Canada and shipped from Japan. At the time, co-owners Capital Power and TransAlta handled all aspects of construction, with engineering support from WorleyParsons. As a a coal unit, Keephills 3 was equipped with an advanced air quality control system to remove sulphur dioxide, nitrogen oxides, mercury and particulates from the flue gas prior to leaving the stack.
TransAlta said it has retired 3,794 MW of coal-fired generation since 2018, and converted 1,659 MW to natural gas. Canada has a federal mandate requiring the full phaseout of coal-fired electricity generation by 2030. TransAlta itself said it aims to reduce its annual emissions 60% by 2030 and become carbon neutral by 2050.
“Converting to natural gas from coal maintains the current generation capacity of KH3 and reduces our CO2 emissions by almost 50 per cent from approximately 0.86 [metric tons] CO2e per MWh to approximately 0.43 [metric tons] CO2e per MWh,” said John Kousinioris, TransAlta president and CEO.