Energy regulators last month said the Grassy Mountain project, proposed by a unit of Australian billionaire Gina Rinehart's Hancock Prospecting, would not be in the public interest.
The proposals involve buying coal plants in developing economies in Asia and operating them for as long as 15 years before closing the sites ahead of current schedules.
In the short term, emissions are on a rising trend, notwithstanding a temporary decline during the covid-19 pandemic, putting the world a long way off track to reach zero emissions by 2050.