Watchdog: More coal power plants to close than expected

More coal-fired power plants will close because of environmental regulations and competition from other energy sources than previously thought, according to federal watchdogs.

A Government Accountability Office report said 13 percent of coal-fired generation will come offline in 2025, compared with a 2012 estimate that ranged between 2 and 12 percent. The report said that raises concerns about having enough electricity supply to meet demand in certain situations, potentially increasing instances of blackouts.

"Recent and pending actions on the four existing regulations, as well as [Environmental Protection Agency's] recently proposed regulations to reduce carbon dioxide emissions from existing generating units, may require additional agency effort to monitor industry’s progress in responding to the regulations and any potential impacts on reliability," the report said.

In some respects, the 13 percent figure shouldn't be surprising. The EPA predicted coal would supply 30 percent of the nation's power in 2030, down from above 40 percent today, when it rolled out its proposed carbon emissions rule for existing power plants in June. The EPA carbon proposal aims to slash electricity emissions 30 percent below 2005 levels by 2030.