The U.S. Environmental Protection Agency announced specific targets for all states as part of the Obama administration's effort to reduce the pollutants blamed for global warming.
The EPA asked Wisconsin to develop a plan to lower its rate of carbon dioxide emission to 1,203 pounds per megawatt-hour of energy produced. That's 34 percent less than the 1,827 pounds the state emitted in 2012.
Environmental groups were pleased with the proposal, saying the goal was well within reach.
Keith Reopelle, a senior policy director for the environmental group Clean Wisconsin, said the state already has programs mandating that electricity providers derive a percentage of their energy from renewable sources. To meet the EPA's target the state would only have to ramp up its existing programs, not develop new programs from scratch, he said.
"The state, the industry, the utilities already have a ton of experience with these programs," he said. "They don't have to create anything new."
The EPA's plan is expected to be finalized by June 2015.
Any changes to state policy would be implemented by the state Department of Natural Resources. Agency spokesman Bart Sponseller said the DNR staff was still working its way through the 645-page plan, and that it was too early to speculate what shape it would take.
He said state officials would spend the coming year meeting with utilities, environmental groups and others to understand the proposed rules and start developing plans to implement them.
Several Wisconsin utilities, including We Energies and Alliant Energy Corp., said they've already begun reducing emissions and increasing plant efficiency. They said they were waiting to see whether they'd get credit for upgrades that have already been made.
Scott Reigstad, a spokesman for Alliant Energy, said the utility supports a decrease in greenhouse gases and has been planning for reductions for several years. He said company officials were evaluating how the EPA's proposal would impact the utility as well as customer costs.
"I think the proposed rules are ambitious, but there's flexibility as well," he said. "I feel it's a good start."
Options for states to meet their targets include making power plants more efficient, reducing the frequency at which coal-fired power plants supply power to the grid, and investing in more renewable, low-carbon sources of energy.
The Public Service Commission of Wisconsin, which regulates the state's utilities, deferred questions about the proposal to the DNR. But spokesman Nathan Conrad cautioned that the plan could end up costing ratepayers down the line.
Wisconsin Manufacturers and Commerce, the state chamber of commerce, sounded the same warning. The group released a statement saying the rule is "likely to inflict dramatic and irreversible harm to our economy" by hurting jobs that rely upon affordable and reliable energy.
But Reopelle called such concerns "irresponsible." He said electricity rates generally rise over time anyway, and not just because the government has imposed new regulations. He also said rates could conceivably come down as power plants invest more in energy efficiency and renewable sources of fuel.