A recent article in The Wall Street Journal highlights a growing trend among power companies to switch from coal to natural gas or other less-polluting fuels. According to The Journal, major utilities such as Calpine, Progress Energy, and Southern Co. are making this move in response to “tighter clean-air rules and big gas finds expected to keep prices low for years.”

Progress Energy of Raleigh, N.C., intends to shut 11 coal-burning plants in North Carolina by 2017, representing about a third of its capacity there. It is building gas-fired plants at two of the four sites. Spokesman Mike Hughes said it would cost $1.5 billion to swap coal capacity for gas capacity but would have cost more than $2 billion to equip the coal units with pollution-control equipment.

After 2017, Progress will have only three coal-burning power plants in North Carolina—basically just units that were big enough and new enough to justify a $1 billion investment in scrubbers.

Another factor behind this major shift is that the chimera of “clean coal” has ultimately proven to be far more costly and much less practical than originally anticipated by its proponents:

Early in the decade, many utilities said they intended to build coal units, but most projects have been canceled due to concerns about pollution and the impact of carbon dioxide on climate change.

Some of those that have gone forward have experienced startling cost overruns. Perhaps the most prominent is Duke Energy Corp.’s “clean coal” plant in Indiana, which is 57% complete. Duke said this month the Edwardsport project’s expected cost has ballooned by about $900 million since 2007, to $2.88 billion from $1.98 billion. The current price tag is $530 million more than the amount approved by Indiana regulators. Duke blames “design evolution.”

The Edwardsport plant will convert coal to a cleaner-burning flammable gas. Duke warned, in a regulatory filing, that the plant’s costs could push up electricity rates by nearly 20% after 2012, when it enters service.

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