SALT LAKE CITY — Utah is among two dozen states across the country mounting a legal challenge to the U.S. Environmental Protection Agency's Clean Power Plan regulation, asserting the rule is illegal because it goes beyond the government's authority.

The suit was filed in the District of Columbia Circuit Court of Appeals on Friday, the same day the rule was formally published.

Other challengers to the rule — which targets greenhouse gas emissions from existing power plants — include Murray Energy and the American Coalition for Clean Coal Electricity.

The Clean Power Plan seeks to cut emissions across the country by 30 percent by pushing electricity generation from renewables and natural gas.

Under the plan, which is up for a 60-day comment period, every state has an emissions target it is required to meet to be in compliance with the EPA. If states don't come up with their own emissions reduction plan, the EPA will craft one.

"I think that the bottom line is that we do have serious legal questions about the plan," said Laura Nelson, executive director of the Governor's Office of Energy Development.

Utah was also among the states that asked early on for a delay of the rule's implementation pending the outcome of anticipated legal challenges, but that request was denied by the courts.

Nelson added that beyond the legal challenge, the Utah Department of Environmental Quality is looking at compliance options, and what type of impact the Clean Power Plan will have on the state as it is rolled out.

"We have to consider things like how do we grow. If we are going to be a pro-growth state, how do we grow and add new resources," Nelson said.

Utah, like the other states, has two different "targets" to meet that are contingent on which approach it takes to measure emissions.

Under a rate-based approach, Utah's final target it has to achieve by 2030 is a reduction of 37 percent from 2012 emission levels, or a reduction of 1,179 pounds of emissions per megawatt hour of electricity generated.

A general "mass" reduction in the amount of emissions would be at 23 percent.

The plan impacts 11 power plants in the state. Five of those are coal-fired power plants under state jurisdiction, one is a coal-fired plant on Native American reservation lands and the remaining five are natural gas power plants. Under the rule, states have until Sept. 16 to come up with an emission reductions plan or ask for an extension.

Coal-dependent states argue that the EPA's Clean Power Plan oversteps the provisions of the Clean Air Act and goes beyond the scope of the federal government's authority.

They argue that — just like the failed mercury emissions rule struck down by the U.S. Supreme Court — the EPA fell down on the job by not appropriately measuring the costs of regulation they contend is over-reaching.

Multiple clean energy groups, environmental and conservation organizations have hailed the regulation as the single most significant step the White House has taken to counter the effects of climate change.

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