Louisville Gas & Electric and Kentucky Utilities, subsidiaries of Pennsylvania-based PPL Corp., announced plans last fall to retire the plant in April 2015 to comply with new federal Environmental Protection Agency edicts, in particular the new Mercury and Air Toxics Standards rule.

But Green River may get a longer lease on life, at least until 2017, according to company spokeswoman Chris Whelan.

As of late April, the utilities had not yet requested an extension for the plant that burns about 400,000 tons of Kentucky coal annually. A decision is expected this summer.

Like many older coal plants in the midwestern and southeastern United States, Green River was called upon to help keep the lights and heat on during the bitterly cold winter of 2013-2014. The utilities are concerned about what may happen next winter if the plant is closed and frigid temperatures return to the region.

LG&E and KU had planned to construct a 700-megawatt natural gas-fired plant at the Green River site to largely offset its impending retirement along with those of two other coal plants, Cane Run in Louisville and Tyrone near Versailles, Kentucky. But on April 30, LG&E and KU asked Kentucky regulators to place on hold for 90 days their application to build the gas plant after nine municipal customers said they intend to terminate wholesale power contracts with the utilities.

Green River’s first two coal units were built in 1950. Two more coal units went online in 1954 and 1959. In January 2002, the initial two units were retired.

In 1974, KU’s first scrubber to reduce sulfur dioxide emissions was installed at Green River.