Wendy Koch

USA TODAY

Politically "red" and "blue" states are increasingly turning green as they push energy efficiency and renewable power to save money and protect the planet, says a report today with prominent bi-partisan support.

In the last two years alone, GOP-dominant red states have adopted policies that could serve as models for others seeking to meet proposed federal targets for reducing heat-trapping carbon dioxide emissions, according to the "State Clean Energy Cookbook" by Stanford University and the Hoover Institution.

"There's no blue or red tinge to it. It's across the board," says George P. Shultz, co-chair of Hoover's Shultz-Stephenson Task Force on Energy Policy and U.S. secretary of State, Treasury and Labor under two GOP presidents. He says the new report shows "what works and what doesn't."

• Mississippi updated its commercial building code last year to a strict international standard that limits energy use, becoming the first Southern state to do so. Prior to the update, in 2012, the American Council for an Energy-Efficient Economy ranked it lowest among states for energy efficiency.

• North Carolina is rapidly becoming a solar hotbed. It ranked third among states, after California and Arizona, for its amount of solar capacity installed last year, according to the Solar Energy Industry Association. One of its largest utilities, Duke Energy, got the state's go-ahead in December to offer green power — produced in and out of the state — to commercial customers like Google that run energy-hungry data centers.

• Arizona's largest utilities have pioneered time-of-use metering, in which customers are charged a lot less for using power during off-peak hours than during peak times. Last year, California moved to follow in its footsteps by rolling out its version.

• Colorado, considered a purplish state, was first to allow "community solar gardens," in which people who don't have rooftops viable for solar panels can jointly develop a project that will produce grid-connected power. In the last year, Minnesota and California have approved similar programs.

"There are innovative and effective policies in a number of states, and we need to do a better job of replicating them," says study co-author and former U.S. senator Jeff Bingaman, D-N.M., who worked on behalf of Stanford's Steyer-Taylor Center for Energy Policy and Finance.

Dan Reicher, executive director of the Steyer-Taylor Center, says some blue, or typically Democratic-voting, states are pushing green energy for environmental reasons, while red states are doing so to save money and to improve the electric grid's reliability by diversifying power sources.

In the last decade, as its costs have fallen, solar and wind energy have grown markedly nationwide. So, too, has the number of energy-efficiency programs. Vicki Arroyo, executive director of the Georgetown Climate Center, a research group, says 40 states now require or encourage a certain amount of their energy be obtained from efficiency measures, renewable power or both.

Still, renewable energy is being challenged by low natural-gas prices, and there's also significant GOP opposition to a new Environmental Protection Agency proposal that encourages its development.

In June, the EPA proposed a national 30% cut in carbon emissions from existing power plants by 2030. It gives states varying reduction targets that can be met by closing coal-fired plants, switching to natural gas, promoting renewable power or saving energy.

A dozen states, led by coal-heavy West Virginia, are suing the EPA to block its proposed rule, which is slated to be finalized next year. Co-filers include Alabama, Indiana, Kansas, Kentucky, Louisiana, Nebraska, Ohio, Oklahoma, South Dakota, South Carolina and Wyoming.