New research from the Brattle Group -- an update to an analysis conducted in 2010 -- finds that 59,000 to 77,000 MW of coal plant capacity are likely to retire over the next five years as a result of the impact of emerging Environmental Protection Agency air quality regulations on coal-fired power plants. This is approximately 25,000 MW more than previously estimated.

Since the 2010 analysis was conducted, both natural gas prices and the projected demand for power have decreased, and environmental rules have been finalized with less restrictive compliance requirements and deadlines than previously anticipated. As a result, coal plant retirements are accelerating.

The financial and operational implications could be substantial, even if overall reliability is not significantly affected, according to the study's authors who found that $126 to $144 billion will be needed to retrofit and replace coal capacity.

Approximately 80 percent of the likely coal plant retirements will be generating plants owned by traditionally regulated utilities, such as investor owned utilities and public power companies, the study says.

As of July 2012, about 30,000 MW of coal plants (roughly 10 percent of total U.S. coal capacity) had announced plans to retire by 2016.

For more:
- see the 2012 report
- see the 2010 analysis