Natural Gas Overwhelmingly Replacing Coal, Says Report
The growth in natural gas–fired generation in the U.S. since 2007 has overwhelmingly displaced coal-fired generation, according to a report from the Breakthrough Institute released Dec. 15.
Consistent with the impressions of power sector observers, but in contrast to previous claims by environmental groups that growth in gas is offsetting renewables and nuclear while coal has been mostly offset by wind, the report—which disaggregated Energy Information Administration generation data down to North American Electric Reliability Council (NERC) regions—found that areas of the country experiencing the greatest growth in gas generation also saw the biggest drops in coal.
Two NERC regions, the Reliability First Corporation (RFC) and the Southeastern Electric Reliability Council (SERC), accounted for 80% of the decline in coal generation and 85% of the growth in gas nationwide. In those regions, gas offset 53%, while declining demand accounted for 40% and wind about 6%.
Interestingly, both regions saw net increases in nuclear and hydroelectric generation.
Another 11% of the growth in gas occurred in the Florida Reliability Coordinating Council (FRCC), where it offset a mix of coal and fuel oil. The remaining 20% of the decline in coal occurred in three other regions, where it was offset in roughly equal shares by gas, wind, and falling demand.
Meanwhile, the Midwest Reliability Organization, the Southwest Power Pool (SPP), the Texas Regional Entity (TRE), and the Western Electricity Coordinating Council, the four regions that saw the largest growth in wind—making up 82% of national growth—saw relatively little decline in coal generation, about 9% of the national total. There, wind offset a variety of generation, as those regions all saw declines in coal, gas, hydroelectric, and nuclear. Approximately 91% of the decline in nuclear generation occurred in regions where there was strong growth in wind.
Only one region, RFC, saw both a large decline in coal and significant growth in wind. However, the amount of new wind generation could account for only a small fraction of the decline in coal; most was accounted for by new gas and falling demand.
Nationally, the growth in wind may have offset very little of the decline in coal. Assuming the growth in wind offset other generation sources in rough proportion to their respective decline at the regional level, new wind generation since 2007 can account for only 1.2% of the total decline in coal generation, the study found.
Because new gas has overwhelmingly displaced coal, the study argues that new gas-fired generation has nearly the same carbon mitigation effects as new wind, which appears to have offset a mix of carbon-emitting and carbon-free generation.
The study also found that the two regions experiencing increasing demand—SPP and TRE—largely met it with new wind, while the three regions seeing the largest growth in gas all experienced falling demand. This suggests, the study argues, that new gas-fired generation is not driving increased electricity demand.
—Thomas W. Overton, JD is a POWER associate editor (@thomas_overton, @POWERmagazine).