The move, completed last month, should reduce nitrogen oxides emissions by about 30 percent, said John Bleem, Platte River Power Authority customer and environmental services division manager.
Platte River spent a total of $11.5 million as it shut down its facilities to perform maintenance and replace parts and machinery while making the upgrade.
The investment helps Rawhide maintain its status as among the nation’s cleaner power plants, though environmentalists say it could do more.
They say that recent improvements by Rawhide to reduce its nitrogen oxides do little to reduce climate-altering carbon dioxide emissions.
“We need to move away from reliance on coal and shift towards reliance on cleaner energy sources,´ said Gwen Farnsworth, senior energy policy advisor for Boulder-based environmental group Western Resource Advocates.
Rawhide emits less sulfur dioxide and nitrogen oxides on average compared with other plants throughout the United States, according to Platte River.
Citing Environmental Protection Agency figures, Platte River spokeswoman Rae Todd said Rawhide ranks 153rd out of 472 reporting U.S. coal-fired power plants for nitrogen oxides emissions. It ranks 37th out of 429 plants for sulfur dioxide emissions.
Nitrogen oxides contribute to the formation of ground-level ozone and, like sulfur dioxide, can cause respiratory system problems, according to the EPA.
Platte River also installed equipment in Rawhide to reduce mercury emissions two years before the state of Colorado required the reduction. The utility plans to reduce mercury emissions even further by 2018.
Other coal-fired plants nationwide have struggled to keep up with tightening air pollution regulations. Companies such as GenOn Energy Inc. and Midwest Generation separately announced closures of several coal-fired power plants last month.
The situation may only become more difficult for coal-fired plants.
In late March, EPA proposed the first federal standard to limit carbon pollution from new power plants. The move reflected a trend in the industry to build cleaner power plants, including ones using natural gas, the agency said.
The rule would not affect power plants like Rawhide or plants whose construction will start within the next year, according to EPA.
Bleem credits Rawhide’s relative youth – it started generating commercial power in 1984 – compared with older plants that lack the space to add new emission-control equipment. The power plant also pays more for low-sulfur coal from Wyoming’s Powder River Basin.
“We’re hoping to stay ahead of what the requirements are for future regulations,” Bleem said.
Rawhide maintains a 280-megawatt coal-fired unit as well as five natural gas-fired combustion turbines. Platte River, a wholesale provider of electricity to Fort Collins, Loveland, Longmont and Estes Park, operates the power plant.
Platte River first upgraded the plant to reduce nitrogen oxides by about 40 percent several years ago, Bleem said. The utility spent about $25 million on those upgrades at Rawhide and another coal-fired plant it operates in Craig.
Since then, Platte River has made additional changes to improve efficiency, which has resulted in lower emissions, Bleem said.
Kevin Cross, convener for the Fort Collins Sustainability Group, welcomed the emission reductions, but said he would like to see the plant generate a greater share of its electricity from natural gas and renewable energy.
Rawhide should be converted to burn natural gas to reduce its carbon dioxide emissions, Cross wrote in an email.
In addition, Platte River “should aggressively develop wind and solar generating capacity in order to reduce the use of all fossil fuels to a bare minimum amount within the next two decades,” Cross wrote.
Cities also should step up their efforts to reduce electric energy use by their customers, he added.
Platte River already generates electricity from renewable sources such wind energy and hydropower.
Rawhide also maintains more natural-gas generation capacity – 388 megawatts – than coal. Natural gas provides electricity during Platte River’s peak load periods such as during weekday summer afternoons.
Still, it tends to generate most of its electricity from coal because even with record slumps in natural-gas prices, coal costs less.
“If somebody said, ‘We really want you to run more gas,’ we could do that but it would raise everybody’s rates,” Bleem said.
Environmentalists believe that coal presents indirect costs not considered by utilities.
The toll of coal emissions on environmental and human health could outweigh the savings, Farnsworth said.
“People in the West value highly the natural landscape and clean air,” she said. “That value needs to be integrated into policy and decision-making on our energy sources.”