PORTLAND — The U.S. Environmental Protection Agency wants Maine power plants to reduce emissions by 13.5 percent in 16 years, as part of a national plan to reduce emissions by 30 percent by 2030.

The proposed rule signed Monday by EPA Administrator Gina McCarthy seeks to meet the national goal by giving states until June 2016 — with possible exceptions — to craft plans for reducing emissions of carbon dioxide per megawatt-hour produced by power plants. The rule allows multiple ways for states to cut emissions, including improvements in energy efficiency, increasing adoption of clean power and other methods.

President Barack Obama called for the proposal using his executive authority under the 1970 Clean Air Act.

The proposal’s critics have said the plan stands to increase energy costs, which McCarthy contested.

“The bottom line is that we have never nor will we ever have to choose between a healthy economy and a healthy environment,” McCarthy said during a broadcast Monday morning.

The agency estimates the emissions reduction plan will deliver $90 billion in health benefits based on improvements in air quality and that electric bills will be 8 percent lower if the plan’s 2030 goals are met.

Emily Figdor, director of Environment Maine, said Monday she expects the state will meet its emissions targets through the Regional Greenhouse Gas Initiative program, which the EPA plan cited as a model. That program requires power generators that emit greenhouse gases to pay for emission credits in a regional auction, using that money to make certain efficiency and emission-reduction investments through the state’s Efficiency Maine Trust.

The EPA said in its draft rule that the New England states had, through 2012, invested $460 million through the program, generating an estimated $1.8 billion in lifetime energy savings.

The EPA said 2012 emissions from Maine-based power plants amounted to roughly 2 million metric tons of carbon dioxide, making for an emissions rate of approximately 437 pounds of carbon dioxide per megawatt-hour of electricity. The state’s 16-year goal calls for a reduction to 378 pounds per megawatt-hour.