Will Natural Gas Crowd Out Wind and Solar?

FORTUNE — Daniel Yergin, author of the new bestseller The Quest: Energy, Security, and the Remaking of the Modern World, is one of the planet’s foremost thinkers about energy and its implications. He received a Pulitzer Prize for his previous book, The Prize: The Epic Quest for Oil, Money, and Power. Yergin is chairman and founder of IHS Cambridge Energy Research Associates, is on the U.S. Secretary of Energy advisory board, and chaired the U.S. Department of Energy’s Task Force on Strategic Energy Research and Development. He talked recently with Brian Dumaine about the role natural gas will play in America’s energy future.

Fracking technology has given the U.S. a 100-year supply of cheap natural gas. What’s its impact on coal, nuclear, wind, and solar power?

Inexpensive natural gas is transforming the competitive economics of electric power generation in the U.S. Coal plants today generate more than 40% of our electricity. Yet coal plant construction is grinding to a halt: first, because of environmental reasons and second, because the economics of natural gas are so compelling. It is being championed by many environmentalists as a good substitute for coal because it is cleaner and emits about 50% less carbon dioxide.

Nuclear power now generates 20% of our electricity, but the plants are getting old and will need to be replaced. What will replace them?

Only a few nuclear plants are being built in the U.S. right now. The economics of building nuclear are challenging — it’s much more expensive than natural gas.

Isn’t the worry now that cheap natural gas might also crowd out wind and solar?

Yes. The debate is over whether natural gas is a bridge fuel to buy time while renewables develop or whether it will itself be a permanent, major source of electricity.

What do you think?

Over the past year the debate has moved beyond the idea of gas as a bridge fuel to what gas means to U.S. manufacturing and job creation and how it will make the U.S. more globally competitive as an energy exporter. The President’s State of the Union speech was remarkable in the way it wrapped the shale gas boom into his economic policies and job creation.

I believe natural gas in the years ahead is going to be the default fuel for new electrical generation. Power demand is going to go up 15% to 20% in the U.S. over this decade because of the increasing electrification of our society — everything from iPads to electric Nissan Leafs. Utilities will need a predictable source of fuel in volume to meet that demand, and natural gas best fits that description.

And that won’t make the environmental community happy?

Well, natural gas may be a relatively clean hydrocarbon, but it’s still a hydrocarbon.

So wind and solar will have a hard time competing?

Remember that wind and solar account for only 3% of our electric power, whereas natural gas is 23%, and its share will go up fast. Most of that 3% is wind. Natural gas has a new role as the partner of renewables, providing power when the wind is not blowing and the sun is not shining.