The average capacity factor for U.S. natural gas–fired combined cycle power plants (CCPPs) exceeded that for coal-fired plants in 2015 for the first time since the Energy Information Administration (EIA) has been keeping records, the agency noted on April 4.
Gas generation exceeded coal generation for most of 2015, though coal ended slightly ahead for the year as a whole, and the EIA has already projected that coal will fall behind in 2016. The latest 2015 data, however, noted another element in how the nation’s power mix is rapidly changing.
For 2015, gas CCPPs averaged a 56% capacity factor compared to 55% for coal. That’s a moderate drop for coal over the past decade—capacity factors averaged around 65% during the 2000s—but a big jump for gas. In 2005, gas CCPPs averaged only a 35% capacity factor.
CCPPs, which account for about 53% of U.S. gas-fired capacity, traditionally ran only when all coal generation was online, but in the past decade they have become favored options for baseload generation.
The major driver in coal-to-gas switching over that period has been the price of gas, which has fallen from highs above $10/MMBtu in the late 2000s to under $2/MMBtu this year. That’s made coal-fired generation much less economic in many areas.
- A fall in the price of gas has led to a big shift in the utilization of the nation’s coal and gas plants, with gas-fired combined cycle power plants seeing capacity factors above those of coal plants in 2015 for the first time ever. Source: Energy Information Administration
Not only has the average capacity factor for the nation’s coal fleet fallen, but the number of little-used coal plants has also grown dramatically. In 2015, nearly 150 coal plants ran at capacity factors of 30% or less. While that figure is still roughly equivalent to the number of CCPPs running under 30% capacity factors, it represents a big jump since 2005.
—Thomas W. Overton, JD is a POWER associate editor (@thomas_overton, @POWERmagazine).