CONCORD, N.H. (AP) — U.S. Sens. Jeanne Shaheen and Kelly Ayotte are supporting the Environmental Protection Agency's plan to set standards to limit carbon emissions from power plants.

The agency published its final version of the new regulations Friday. Some states and industry groups dependent on fossil fuels have filed court challenges to the plan.

"Climate change poses a significant threat to New Hampshire's environment and its economy," Shaheen said a news conference with Gov. Maggie Hassan on Monday. "The Granite State is doing its part to reduce greenhouse gas emissions, but we need a federal standard to make sure our country moves forward together."

On Sunday, Ayotte said after carefully reviewing the plan and talking with businesses, environmental groups and other stakeholders, she decided to support it to address climate change through clean energy solutions that will protect the environment.

"I will carefully monitor implementation of the plan to make sure there is sufficient flexibility for New Hampshire to meet its goals and that the plan does not have an adverse impact on Granite State energy costs," she said.

Ayotte is the first Republican in the Senate to break ranks and support the plan that is the centerpiece of President Barack Obama's environmental agenda.

She noted the Department of Environmental Services said New Hampshire has already taken steps to reduce emissions and is on track to meet its goals under the plan, and several businesses have expressed support for it, such as Smuttynose Brewing Company, Timberland and Worthen Industries.

The new rules require states to cut carbon emissions by 30 percent by 2030. Each state has a customized target.

Last week, Hassan sent a letter to the state's congressional delegation urging them to back the proposal.

"We know that a healthy environment and economic development go hand-in-hand, and that's why addressing air quality and climate change is an economic imperative for our state," Hassan said.