Kentucky Utilities and affiliated company Louisville Gas and Electric announced Monday that they expect to shut down three coal-fired electrical generation plants months ahead of schedule as part of their effort to comply with new federal environmental regulations.

The utilities said the three coal-fired plants at their Cane Run Generating Station in Jefferson County will be shut down in May 2015, eight months earlier than expected. That's because the utilities expect their new natural-gas fired power plant to be built on the same site to be operational at that time.

The utilities previously announced plans to end coal-fired power generation at three of its older plants — Cane Run, Green River and Tyrone — by the end of 2015. To offset the 800 or so megawatts of generation that is being lost, the companies have received approval from the state Public Service Commission to build a 640-megawatt natural gas combined cycle generation plant at the Cane Run station. The companies intend to shut down the Green River and Tyrone plants by April 2015.

In moving forward with building the natural gas plant, the company credited a timely turnaround on government permits to moving the project along. Preliminary work has already begun, according to a statement. Full construction, though, is not expected to begin until the first quarter of 2013.

At its peak, the construction work on the site should employ about 250 people, according to the statement.The companies also had initially planned to buy natural gas-fired peaking plants that are used when energy demand is at its peak.

That plan fell through, though, because some federal approval requirements weren't commercially justifiable, spokesman Brian Phillips has said. The utilities recently announced a request for proposals to buy as much as 700 megawatts of generation to help offset the remainder of the losses of coal-fired generation and help meet future increases in demand.