US-based Duke Energy has received an order from a federal judge in Indiana, US, to close three coal-fired units at its West Terre Haute Wabash River Station.

The plant, previously owned by Cinergy, has been found to violate federal emissions standards after the company refurbished the units without a permit.

Duke Energy acquired Cinergy for $9bn in April 2006. The court’s order accelerates that timetable by three years.

Duke Energy has previously stated that units 2, 3 and 5 would retire in 2012 when its integrated gasification combined-cycle plant in Edwardsport, Indiana, commences operations.

The plans must close down by the end of September this year.