Duke Energy Corp. is considering building as many as 15 new natural gas units even as the company commits to eliminating carbon emissions by 2050. In order to still meet its climate target, the nation’s largest utility says it would retire the plants early — after 25 years rather than the usual 40.

“We’ve done analysis that says, ‘Let’s shorten the life of these gas assets,’” Chief Financial Officer Steve Young said in an interview before the company released its quarterly earnings Thursday. “It can still make economic sense.”

Duke, which says adding gas plants could help retire its coal fleet and provide electricity as it transitions to renewables, has proposed six different plans for cleaning up its power mix. All but one includes new gas plants. Still, Duke expects to be able to cut emissions by 56-71% by 2030, depending on which path is approved by state regulators. Not building any new gas plants is the most expensive option and could create reliability problems, according to the utility.

President Joe Biden has set a 15-year timetable for eliminating emissions from the electric system, while states from New York to California have established their own mandates to hasten the shift from fossil fuels to renewables. An expansion of fossil-fuel infrastructure like gas plants runs counter to that goal, environmentalists argue.

“This is the single largest buildout of gas across the country that we’re seeing,” said Tyler Fitch, a policy analyst at clean energy advocacy group Vote Solar who wrote a report on Duke’s plans. “The problem that we’re seeing is that their resource plans, where the rubber hits the road, they don’t reflect the company’s 2050 goals.”