Consumers Energy Co. is proposing to retire two aging coal-fired units with a combined capacity of 515 MW at the Karn generating complex in Bay City, Mich., in 2023, as part of the company's commitment to move away from coal-fired generation, it said in a June 13 news release.

The CMS Energy Corp. subsidiary is to file its integrated resource plan, or IRP, with the Michigan Public Service Commission by June 15, detailing plans to boost the share of its power generation resources from renewables from the current 11% to 37% by 2030 and 43% by 2040. Earlier this year, the company unveiled plans to reduce carbon emissions by 80% and stop using coal-fired generation by 2040.

"This IRP will help guide key decisions in the coming years to make us a cleaner, leaner company for the Great Lakes States," CMS Energy President and CEO Patti Poppe said.

Aside from terminating operations at Karn units 1 and 2, Consumers Energy would also add 5,000 MW of solar through the 2020s, plus wind energy and battery storage. The resource plan is to also highlight the company's blueprint for demand response, energy efficiency and grid modernization.

By 2023, the two Karn coal units will be more than 60 years old. The plant also includes two gas-fired units totaling roughly 1,400 MW of nameplate capacity that began operating in the mid-1970s. According to S&P Global Market Intelligence data, the plant's major sources of coal include Arch Coal Inc.'s Black Thunder mine in Campbell County, Wyo., and Cloud Peak Energy Inc.'s Antelope mine in Converse County, Wyo.