Xcel Plans Emissions Retrofits for Minnesota

Issue 6 and Volume 106.

Minneapolis-based Xcel Energy is proposing voluntary modifications for three coal-fired plants in Minnesota to significantly reduce air emissions and boost power production.

The plan would convert two of the three coal-fired plants to use natural gas while upgrading the third with best available control technology. Converting the Riverside Plant in Minneapolis and High Bridge Plant in St. Paul to natural gas would virtually eliminate emissions of sulfur dioxide, nitrogen oxides, particulate matter and mercury at the two inner-city plants. Retrofitting the King Plant with state-of-the-art flue gas scrubbers and fabric filters would result in a 91 percent reduction in sulfur dioxide emissions, an 89 percent reduction in nitrogen oxides emissions, and dramatic particulate and mercury emission reductions.

The King Plant in Oak Park Heights, Minn., would be retrofitted with BACT at a projected cost of $385 million. Power output would increase from 564 MW to 624 MW.

The High Bridge Plant in St. Paul would be converted to a combined-cycle natural gas facility at an estimated cost of $394 million. The current power plant would continue to run while the new plant is constructed on adjacent property. Then the original plant would be demolished. Sulfur dioxide, mercury and particulate emissions would be eliminated. Nitrogen oxide emissions would be reduced by 97 percent. Power output would increase from 268 MW to 511 MW.

The Riverside Plant in Minneapolis, dating back to 1911, would also be converted to natural gas at a cost of $226 million. New combustion turbines and heat-recovery boilers would be constructed on the location of several of the plant’s retired units.