Massachusetts has supplanted California as the country’s most energy-efficient state, according to a report by the American Council for an Energy Efficient Economy (ACEEE). It is the first time in the report’s five-year history that California has slipped from the top spot.

The ACEEE’s Scorecard—which gauges states' energy efficiency based on their utility and public-benefits funds, transportation, building energy codes, and appliance efficiency, among other criteria—rated Massachusetts at a 45.5 out of a maximum 50 points. California placed second with 44 points, followed by New York with 38, Oregon with 37.5, and Washington, Vermont, and Rhode Island tied with 34.

According to ACEEE officials, states have continued to prioritize energy efficiency despite budget cuts and a bleak economy. “As they have over the past decades, states continue to provide the leadership needed to forge an energy-efficient economy, which reduces energy costs, spurs job growth, and benefits the environment,” says Steven Nadel, the organization’s executive director.

Maryland, one of the six most-improved states on the list, made its first appearance in the top 10. Malcolm Woolf, director of the Maryland Energy Administration, says that the state has saved $91 million since 2009, reduced average peak demand by 600 megawatts, and avoided the power blackouts that plagued much of the region in the summer of 2011.

Rural states, particularly those in the Midwest and South, fared the worst: Alabama, the Dakotas, Kansas, Mississippi, Missouri, Oklahoma, South Carolina, West Virginia, and Wyoming comprised the ranking’s bottom 10 states. Last-ranked North Dakota also happens to be the nation’s fastest growing producer of crude oil.

Though federal agencies like the EPA and the DOE have partnered with states to stimulate energy efficiency programs through grants, the process starts at the state level, a point on which Nadel is emphatic. “States are not waiting for Washington,” he says. “They’re leading.”