Topeka ? New federal clean air rules will require Kansas electric utilities to cut their rate of carbon emissions by 44 percent, a much higher target than most other states’.

That’s because Kansas currently relies heavily on coal for producing electricity — 61 percent of its net generation, according to the U.S. Energy Information Administration — while it uses relatively little natural gas, which produces a lower level of carbon emissions.

That detail of the Environmental Protection Agency’s Clean Power Plan came to light this week when Westar Energy announced plans to retire some of its older, smaller generating units and eliminate 40 jobs in Lawrence, Tecumseh and Hutchinson.

Although the new carbon standards were only part of the reason for Westar’s decision — a company spokeswoman said the units were scheduled for retirement anyway because they had long outlived their expected usefulness — the announcement provided new fodder for Republican lawmakers to lash out at President Barack Obama over his environmental policies.

“The Obama administration has placed Westar in an impossible situation and we now have 40 Kansas jobs that are the first announced victims of the EPA’s Clean Power Plan,” House Speaker Ray Merrick, R-Stilwell, said in a written statement. “This decision was forced upon Westar as a direct result of regulations that killed their ability to retrofit and upgrade existing plants.”

Rep. Dennis Hedke of Wichita, who chairs the House Energy and Environment Committee, and who openly denies that carbon emissions are causing global climate change, predicted more layoff announcements will soon follow.

“Due to the Clean Power Plan, this announcement from Westar is the harbinger for a wave of plant closures across America, resulting in a significant increase in the electric bill of every Kansas family,” Hedke said.

Westar said that while the total number of jobs at the company will decline, it expects to place employees affected by the changes in other open positions within the company.

Nationwide, The EPA expects utilities to cut carbon emissions by 32 percent below their 2005 levels. But different standards apply to each state, based on their current mix of coal and natural gas electric plants.

States have the option of using either of two ways of measuring carbon emissions: a rate-based measurement, measured in pounds of carbon dioxide per megawatt of electricity produced; or a mass-based system, measured by the average annual number of tons of carbon emissions.

According to an EPA fact sheet on Kansas’ standards, using the rate-based measurement, Kansas utilities would be expected to cut their carbon emissions 44.2 percent, from 2,319 pounds per megawatt, down to 1,293.

But that would still be on the high end of the scale, according to EPA. The benchmarks for all states ranges from 771 pounds per megawatt to 1,305 pounds per megawatt.

Under the mass-based measurement, the reduction would be smaller, about 36 percent, to roughly 22 million tons of carbon dioxide per year.

The Clean Power Plan is scheduled to take effect Nov. 13. But a group of 15 states, including Kansas, are suing to block the new rules.

Westar spokeswoman Gina Penzig said the Topeka-based utility has a “diverse portfolio” of energy sources, including coal, gas, nuclear power and renewable resources. But she said coal is the dominant fuel used in its plants because it’s the cheapest.

“We look at the fuel cost associated with each type of generation, and we look at what is least costly,” she said. “Even with lower natural gas prices, it’s still cheaper to produce electricity with coal.”