According to a new study by the Rocky Mountain Institute, some states can produce goods at a rate three times higher relative to energy use than others.

The report, which compares the states' gross domestic product and energy consumption per capita, says that if all states were to be as efficient as the top states, the country could save up to 1.2 million gigawatt hours of electricity.

Adopting the most efficient practices and available technologies could close the gap between the states within 10 years, according to RMI. "Assessing Electric Productivity and the U.S. Efficiency Gap" adjusts or factors including population density, types of industries in the states and weather, according to Natalie Mims, an RMI consultant and co-author of the report.

The large gap in efficiency is primarily because of three factors, Mims says: state incentives to encourage utilities to be energy efficient, building codes, and the presence of third-party organizations to pressure utilities to be more efficient. The top five states, which also include Delaware and California, are progressive that have programs that encourage customer energy efficiency through weatherization and other conservation efforts.

Alaska is unique on the list because of its heavy reliance on hat is locally available natural gas instead of electricity. Because natural gas is used to transmit energy instead of electricity, the state rates well, according to Mims.

The most inefficient states include Kentucky, Mississippi, Alabama, South Carolina and Idaho, which also happen to be among the poorest in the nation. But Mims says its wrong to make a connection between wealth and efficiency. "In the Southeast it is only the utilities, and not the states or third-parties that are pushing for energy efficiency mandates," according to Mims. Also, the cost of electricity in a region has only a limited impact on per capita consumption, she says.

The study did not evaluate the energy efficiency of the utilities themselves in producing power. Utilities in states where revenue is tied to selling more kilowatt hours of electricity (including those in the lower South) have little incentive to encourage customers to be energy efficient; states with decoupled rates (such as in California) tend to be more efficient, Mims says.

In a future report RMI will seek to quantify the physical factors relating to energy efficiency, including "CFLs, weatherization, installation of more efficient appliances, and updating heating and air conditioning systems."