Officials, who called the work at the Stanton plant a “significant step”, said that the scrubber for Unit 1 was placed into service on June 13 and was tied in during a regularly scheduled maintenance outage.

Unit 2’s scrubber was put online last October after being tied in during a regular maintenance stoppage.

The Leland Olds plant, which began generating in 1966, burns more than 3 million tons of lignite coal annually.

“The units at Leland Olds did not have scrubbers installed when they were constructed,” officials said.

“The Leland Olds Station has always been in full compliance with its federal and state environmental permits.”

The Leland Olds Station was the first power plant built by Basin Electric, and the company said it had been the foundation for developing its generating fleet.

Leland Olds Station plant manager Mark Thompson said the scrubber project was approved by Basin Electric’s directors in March 2006 following an extensive engineering study to determine the plant’s remaining lifespan.

“That study showed the plant could be operated safely and effectively for at least 20-30 more years,” he said.

The adjustments were made to bring the facility in line with the US Environmental Protection Agency’s Regional Haze Rule set to go into place at the end of 2013.

The first unit at the Leland Olds Station has a generating capacity of 222 megawatts and was placed in commercial operation in 1966 at a cost of $36 million. The second unit has a generating capacity of 447MW and was placed online in 1975 with a $109 million price tag.

Leland Olds Station currently employs 160 workers.