Over the past decade, the electricity producing fleet of power plants has begun to noticeably shift. While the country's nuclear and coal fleets continue to age, its natural gas power plants are getting younger and leaner. From 2000-2010, natural gas power plants topped the leader board for retirements and additions to the generation fleet. Over this decade, 64% of the power plants that were retired in the United States were natural gas-fired.

But, over the same period of time, natural gas represented 81% of the new power generation capacity additions in the United States. with a spike in new capacity installations in the early part of the decade.

The average age of these recently retired natural gas power plants was 48 years, with the oldest having been built in 1912. And, the majority of these retired plants were simple cycle steam turbines, making them markedly less efficient than their combined-cycle counterparts.

While coal plant retirements were significant over this period, they were smaller in overall magnitude (and much less in terms of relative percentage of generation) compared to natural gas.

Photo credit:

1. All graphics courtesy of the U.S. Department of Energy, Energy Information Administration (EIA)