• Cherokee Station Unit 1, in Adams County, in 2011
• Cherokee Station Unit 2 in 2011
• Cherokee Station Unit 3 in 2017
• Arapahoe Unit 3, in Denver, in 2013
• Arapahoe Unit 4 would stop burning coal in 2014 and switch to natural gas
• Valmont Station Unit 5, in Boulder, in 2017
Denver The Colorado Public Utilities Commission voted Monday to shut six aging Front Range coal-fired power units and allow Xcel Energy to replace them with a new $530 million gas-fired plant.
Pollution controls, with a $340 million price tag, also were approved for the coal-burning Pawnee plant near Brush and the Hayden plant.
The commission still must decide what to do with the largest coal-burning plant in the Denver area — the Cherokee 4 unit.
"Cherokee 4 is the largest source of air pollution in the Denver area, and it needs to be shut," said John Nielson, energy-program director for the environmental-policy group Western Resource Advocates.
The closures, which will occur between 2011 and 2017, are part of Xcel's proposal to meet the state Clean Air- Clean Jobs Act, which seeks to cut nitrogen-oxide pollution by 70 to 80 percent.
Xcel would receive accelerated cost recovery for the investments in a comprehensive plan to cut pollution under the law.
The state is out of compliance with federal clean-air health standards and has to submit a plan next year to the Environmental Protection Agency showing steps to cut pollution.
Xcel, which serves 1.4 million people in Colorado, proposed a series of options with costs that reached as high as $1.3 billion.
"None of these scenarios are cheap," said PUC staffer Ron Davis. "Rates are going to rise."
Commission Chairman Ron Binz said the hope was that a comprehensive plan to cut pollution would be "more cost-effective."
While six units at three plants will be shut, the fate of Cherokee 4 is more complicated. Xcel says it needs that unit or another one to ensure electricity reliability in the region.
Xcel's preferred alternative is to add pollution controls to Cherokee 4 and keeping burning coal.
Western Resource Advocates and other environmental groups want Cherokee 4 closed in 2017 and replaced with a gas-fired unit.
On Monday, Binz offered another option — switching Cherokee 4 to natural gas to allow for more time to explore other alternatives.
The commission is slated to make a decision Wednesday and to review cost issues related to the plan.
"We will have to see the whole package to determine if it is doable," said Karen Hyde, Xcel vice president for rates and regulation.
Mark Jaffe: 303-954-1912 or email@example.com