Bloomberg New Energy Finance predicts another 236 could follow suit.

By the end of the decade, it is predicted 25% of the US coal fleet would have been forced into closure.

In the EIA’s December 2012 survey, of the 536 coal-fired plants in the US, 84 announced boiler retirements and 146 are listed as likely to retire.

In some states the situation has become so dire that coal plants have become impossible to sell.

ED Edwards’ power plant, in Illinois, made headlines when owners Ameren Corp paid Dynergy to take the plant, and four others, off its hands. The reasons for doing so were issues meeting state and federal regulations and increased competition from natural gas.

Ameren’s decision is becoming increasingly common as companies pull out of investments in aging coal plants that no longer meet federal requirements and cannot compete with the prices of natural gas.

Bloomberg reports that coal accounted for 39% of total US electricity consumption last year.

This was down from 2003-08 when coal accounted for 50%. However, it was a slight rebound from 2012, when coal accounted for 37% of total electricity consumption.

Bloomberg predicts coal will regain some holding, accounting for more than 40% of total electricity usage over the next three years.

With relatively low natural gas and electricity prices and therefore a lack of return for coal plant operations, it raises the question of the viability of investing in cleaning up the ageing plants, which will drive prices higher.

With the establishment of a national mandate requiring all plants to reduce mercury emissions, plant owners, who have previously avoided such modifications, are forced to make a decision to invest, sell or close the plants.