There are so many ways to be “green” these days, one of the easiest—and probably most important ways is to green your energy use by choosing renewable or sustainable energy, like wind or solar. Depending on where you live throughout the US, your utility can offer you, in addition to incentives to purchase solar systems, the ability to purchase clean energy. Peoples’ investment in such energy helps ensure that utilities will continue to invest in green energy.

To help spotlight which utilities and states have the best green programs, the National Renewable Energy Laboratory (NREL) released its “Top 10” assessments of green power programs, evaluating the programs by a variety of metrics. The top 10 categories the lab evaluated the programs in were: total sales of renewable energy to program participants; total number of customer participants; the percentage of customer participation; green power sales as a percentage of total utility retail electricity sales; and the lowest price premium charged for a green power program using new renewable resources.

"Participating in utility green power programs allows consumers to support renewable energy above and beyond what utilities are procuring to comply with state renewable portfolio standards," NREL Analyst Jenny Heeter said. "These utilities are offering first-rate programs that give their customers an opportunity to support renewable energy deployment."

“Wind energy represents approximately 85 percent of electricity generated for green energy programs nationwide,” NREL said. But six utilities—the last two Alameda Municipal Power in Calfornia and PacifiCorp in Oregon—sourced at least 2 percent of their energy from solar. That group was led by California’s Sacramento Municipal Utility District, which sourced 14.5 percent of its green pricing program's power through solar.

NREL has been publishing the lists since 2000. At that point the top participation rate in a renewable energy program was Wisconsin’s Madison Gas and Electric 4.7 percent participation rate in its wind energy program. Thirteen years later its participation rate in green programs is up, to 9.4 percent. But it’s fallen to third place while the City of Palo Alto’s municipal utility in California has the highest participation rate with 18.2 percent of customers enrolled in its green energy program.

In terms of premiums charged for enrolling in a green program, in 2000 Austin Energy’s additional charge of .4 cents per kilowatt hour, offered the best deal. The best deal as of December 2012, was the City of Ponca’s offering in Oklahoma. Participation in the wind-rich state’s green energy program averaged .8 cents per kilowatt hour—less—than purchasing conventional energy from the utility.

Other top 10 categories have evolved over time and aren’t directly comparable. In terms of overall megawatts per hour support Oregon’s Portland General Electric overtook Austin Energy, selling 834,125 megawatt hours of green energy in 2012. “Green power sales of the top 10 utility programs by sales exceeded 4.2 million megawatt hours in 2012, up from 3.9 million megawatt hours in 2010,” NREL stated.