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Big Stone coal plant’s new air-quality control system is commercial

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World Coal,

Big Stone 475 MW coal-fired power plant’s new air-quality control system (AQCS) is commercially operational. The three-year US$384 million project is now complete and the system is reducing emissions in compliance with new federal and state regulations.

The project is intended to help the plant owners –Otter Tail Power Co., Montana-Dakota Utilities Co. and NorthWestern Energy – balance their commitments to environmental stewardship with cost-effective service for their customers by enabling them to responsibly generate base-load electricity from coal at Big Stone. The new system reduces nitrogen oxides and sulfur dioxide emissions by approximately 90% and mercury emissions by approximately 80%.

For all three companies, making environmental upgrades at this plant was less expensive than building a new plant. “Our analysis showed alternatives, such as building a new generation resource, to be more than 30 percent more expensive,” commented Otter Tail Power Company President Tim Rogelstad. Otter Tail Power Company operates the plant on behalf of itself and the two other owners.

The AQCS is a result of the Environmental Protection Agency (EPA) requiring the State of South Dakota to submit an implementation plan describing how Big Stone Plant would reduce its emissions in compliance with Best Available Retrofit Technology (BART) guidelines. The EPA approved South Dakota’s plan in 2012. The AQCS project is complete more than a year before the spring 2017 deadline to comply with the South Dakota Regional Haze State Implementation Plan.

“Despite challenges along the way, the project was completed on schedule. Because of lower-than-expected procurement and engineering costs, the project cost about US$384 million—a 21% reduction from the original budget of approximately US$490 million. And with workers putting in more than 2.5 million labour hours, our safety record is stellar,” detailed Rogelstad.

Big Stone plant is located near Big Stone City, South Dakota, and in close proximity to Milbank, South Dakota, and Ortonville, Minnesota.

During the initial planning phase, the AQCS project team contacted the communities through informational meetings and helped businesses and government entities in order to plan for an influx of workers to the area during the project.

“We extend many thanks to the Big Stone City, Milbank, and Ortonville communities and surrounding areas. We greatly appreciate your welcome, assistance, and patience as we reaffirmed our commitment to environmental stewardship with cost-effective service for our customers through this project,” said Rogelstad.

Edited from press release by Harleigh Hobbs

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