Addressing the IHS CERAWeek conference, McCarthy also dismissed claims that the controversial new regulations, dubbed the Clean Power Plan, would lead to blackouts during such transitions.

Yet McCarthy said coal would stay one of the US’ top sources of US power, providing about 30% of projected capacity in 2030, all the while utilities and states would be modernising plants, improving efficiency and generating more power from sources cleaner than coal like natural gas and wind.

“Let me be clear: There is no scenario, standard or compliance strategy I will accept where [power] reliability comes into question – period,” she said.

Obama’s plan, expected to be finalised this US summer, has already drawn lawsuits as states including Texas have said that the proposals would force coal plants to retire prematurely and thus threaten power reliability.

McCarthy, however, was undaunted, saying the new rules – which will establish the country’s first limits on carbon pollution from existing fossil fuel-fired power plants – do “not seek to swim against the current. It’s wind in our sails”

She was adamant that industry would find a way through the new regulations, and have indeed already sunk millions of dollars into technology to use energy more efficiently while bringing online increasingly more gigawatts of “climate-friendly” power.

“This is some serious investment,” McCarthy said. “Clearly, you’re spending that money increasingly on strategies that reduce carbon, like efficiency or solar, or just on making sure your operations are as up-to-date and high-performing as possible, because the economics make sense.”

The new regulations will see electric utilities to reduce carbon dioxide emissions by 30% from 2005 levels by 2030.

It drew the ire of former Peabody Energy CEO Greg Boyce, who said: “Why are we working so hard to push ourselves off the cliff?”

McCarthy, however, said industry “never fails to meet the standards we set. That’s because they are very innovative”