The U.S. practice of “decarbonizing” its electricity supply by switching from coal to natural gas is coming into sharp focus, after new data showed the country’s greenhouse gas emissions increasing by 3.4% in 2018, and its electricity sector emissions rising for the first time in five years.
Until now, the U.S. formula for addressing climate change has been simple: “Retire old coal plants, replace them with natural gas, add a dash of renewables,” E&E News reports. But now, “the increase raises questions about America’s reliance on coal-to-gas switching to drive down greenhouse gas emissions. And it underscores the stark reality facing U.S. carbon cutters: The chief source of emissions reductions in recent years has not been wind or solar. It’s a fossil fuel.”
While it may be easier for a business-as-usual power utility to build a natural gas plant, “this isn’t the huge transition that is necessary to meet the climate challenge,” said Prof. Leah Stokes, a power sector specialist at the University of California, Santa Barbara.
E&E cites Alliant Energy Corporation, Ameren Corporation, American Electric Power, Consumers Energy, DTE Energy, and WEC Energy Group Inc. as utilities that have vowed to cut their emissions 80% by 2050. Companies like Xcel Energy and Northern Indiana Public Service Co. are replacing their fossil generation with renewables and, in Northern Indiana’s case, energy efficiency.
“But those cases remain an exception to the rule,” E&E notes. “More frequently, power companies have turned to gas to replace aging coal facilities, like in the case of DTE, which is building a nearly US$1-billion gas plant to replace several old coal facilities” and hoping to reduce emissions by 70%. Across the board, U.S. utility installed 46.3 gigawatts of new natural gas capacity between 2013 and 2018, including 21 GW in 2018 alone. Over that same period, wind and solar added 33 and 23 GW, respectively.
“I’ve also said to people the CO2 reduction is not an exercise in purity,” CEO Gerard Anderson told E&E. “We got to get it done, and we got to get it done in a way that works for our society.”
“Gas is going to continue to grow. Coal retirements will continue,” added Morningstar Inc. power sector analyst Matthew Hong. “What the industry is trying to figure out now is reliability. With the growth in solar and wind generation, natural gas for the time being is going to be needed to ensure the reliability of electricity.”
(Utilities still committed to that line of reasoning may not have spotted the bombshell news from Hawaii, where solar+storage costs have fallen 42% in three years and are now coming in as low as 8¢ per kilowatt-hour.)
“Power companies’ reliance on gas is a double-edged sword for climate hawks,” E&E notes. “When a natural gas plant replaces a coal facility, there is a climate benefit,” with emissions estimates falling by about half. “But when gas plants run harder to meet an increase in electricity demand, emissions go up,” a reality that points to the “diminishing climate returns” in adding more gas plants.
“The climate cares about actual tons, not [emissions] intensity,” said University of Texas, Austin power sector researcher Joshua Rhodes. “Any natural gas built to serve new demand will not have climate benefit.” Which means that, “at some point, for our carbon emissions to continue to go down, traditional natural gas is not going to get us there anymore.”
U.S. Energy Information Administration data show gas plant emissions growing 59% between 2005 and 2017, E&E writes.