The Potential Downside of Natural Gas

Coal generation peaked in 2007 at a little over two billion megawatt hours while in 2013 it dropped to 1.58 billion, according to the Energy Information Administration. (A megawatt-hour, or 1,000 kilowatt-hours, is the amount of electricity a typical suburban house uses in a month.) Over the same time, gas generation started at 857 million megawatt-hours and ended at 1.2 billion.

If all the increase in gas-fired generation replaced coal, then the switch produced savings of 113.1 million tons of carbon a year.

But natural gas is starting to replace nuclear power, which can be seen as wiping out about 10 percent of the savings, because a reactor has a carbon footprint of nearly zero. Last year the owners of five reactors announced they would retire them. Some had mechanical problems or political opposition; some did not. But all were challenged by the drop in prices on the wholesale market, driven down by natural gas. And several other reactors are losing money and could close this year.

It is probably also reducing the growth of wind energy, many analysts said. Wind contributes only slightly to generation capacity needs, but whenever it runs, it saves fuel, mostly natural gas, and that gas is now worth about half of what it was a decade ago.

“There is no question that depressed natural gas prices have had an adverse effect on the wind and solar industries,” said Kenneth Kimmell, the president of the Union of Concerned Scientists and the former commissioner of environmental protection in Massachusetts. “It’s stunting zero-carbon alternatives.”

He added, “Low natural gas prices decrease the benefit of energy-efficiency investments as well,” since the kilowatt-hours saved by installing a better air-conditioner or light bulb are worth less than they would have cost in a world with higher gas prices.