Kay Opitz appreciates the sun.

When the warm, golden rays hit the roof of her town of Westport home, they are helping to generate both power and money for Opitz and her family.

Thirty-six photovoltaic solar panels installed on the roof produce electricity, and Madison Gas & Electric buys that power from the Opitz household through the utility 's Green Power Tomorrow program.

"Some people like fast cars or race horses. (This is) something that makes me feel good, " Opitz said.

MGE 's Green Power Tomorrow is one of more than half-a-dozen programs offered by Wisconsin utility companies as a way to tap into more renewable sources of energy to meet the electricity needs of their communities and, therefore, to reduce the pollution blamed for global warming.

More than 45,000 households and businesses participate in green-pricing programs throughout Wisconsin, according to figures compiled by RENEW Wisconsin.

Across the U.S., more than 750 utility companies in 38 states offer such programs, making them available to more than half of all electricity customers in the nation. If areas that allow retail electric competition are added to the total, green power is available to consumers in all but four states.

Typically, under such programs, ratepayers have the option of buying some or all of their power from renewable sources -- mainly wind -- and paying a premium to do so.

It doesn 't mean, though, that if you sign up, your home 's circuits are hooked up to a wind turbine.

"They don 't necessarily get the renewable energy to light up their light bulb, " said Timothy Le Monds, spokesman for the Wisconsin Public Service Commission. "What they 're doing is obligating the utility to generate the amount of energy that customer has used through a renewable source. "

Wisconsin utilities already produce 1,120 megawatts of the power they use from renewable sources, an amount comparable to the output of the coal-fired Columbia power plant near Portage. By 2015, they are required, by state law, to produce 3,000 megawatts, or 10 percent of their electricity, from renewables. Green power programs are in addition to those amounts.

They are not just symbolic, said Ed Blume, RENEW Wisconsin communications and outreach director. "Those turbines are going up in Wisconsin, stimulated by the (utilities ') renewable portfolio standard plus consumers ' interest, " he said.

More public interest

From 2000 to 2006, the number of participants in green pricing programs nationwide jumped nearly fourfold, from 132,700 customers to more than 486,000, a December 2007 report by the National Renewable Energy Laboratory shows.

"Absolutely, enthusiasm is growing. As soon as a utility announces that they are adding wind power and increasing opportunities for people to buy green energy, people jump at the chance, " Blume said. "It 's very convenient to just say, I 'll buy green energy, ' much more convenient than installing solar panels. "

Convenience wasn 't the issue for Kay Opitz but she was mindful of the cost. The photovoltaic panels on her home cost $41,000. "It 's a considerable investment. The payback would have been 40 years ... I didn 't know if I 'd live that long, " she said.

MGE started its green power program in 1999. It expanded the terms in January, after signing contracts to buy power from wind farms in northern Iowa and in Dodge and Fond du Lac counties, in addition to the Kewaunee County wind farm MGE owns. So, three times as many people were able to sign up for renewable power -- and they did.

"We were at (subscriptions totaling) 15 to 16 million kilowatt hours, depending on how much wind blew in a year. This will top 45 million kilowatt hours. When we hit that target, customer response was still strong and growing, " said Greg Bollom, MGE assistant vice president, energy planning.

Metcalfe Sentry Hilldale was one of the businesses that signed up to receive 100 percent of its power from renewable sources. "When we heard about the program, it just lit us up over here. We 've always been interested in trying to find ways to reduce our impact on the environment, " said president and co-owner Tim Metcalfe.

The move raised the grocery store 's electric bill about 10 percent, but Metcalfe said it makes a statement "that we 're doing the right thing. ... Our customers will look at us as, hopefully, a leader in terms of the green movement in this area. "

MGE also added an offer in January to buy electricity for 25 cents a kilowatt hour from residents and businesses that install solar units and add their power to the electricity grid. That program was set to cap at 300,000 kilowatt hours.

"We filled it up really fast. We actually have customers on the waiting list, " said Bollom.

For Opitz, the MGE buyback, coupled with a $10,000 rebate from the state 's Focus on Energy program and about $2,000 in federal tax credits cut the payback period to 16 or 17 years.

"I know that it 's not polluting anything. It 's paying back slowly, but it 's clean and it 's not coming from any foreign country, " said Opitz.

Kay, her husband, Konrad, their three children and Konrad 's father have become used to having panels on the wide roof of their home. They installed a set in 2006 that ties in with a high-efficiency boiler and heats their home in the winter, their swimming pool in the summer and their hot water year-round.

And they 're not the first in their family. Kay 's mother, Susie Jablonic, has had two solar hot water panels on her Vilas Park-area home since 1982.

Three energy sources

Wisconsin Power & Light also offers green pricing through its Second Nature program; about 7,700 residential and business customers are enrolled in Wisconsin. Initiated in 2001, most of the renewable energy is wind power, 11 percent is landfill gas from Mayville and 2 percent comes from a dairy farm dung digester in Fond du Lac County.

"We 've got a pretty solid commitment to renewables, " said WPL spokesman Rob Crain. "We have $1 billion committed to wind farms by the end of 2010 and we 've proposed the first hybrid coal plant in Wisconsin that 's going to use renewables. "

Customers can sign up for 25 percent, 50 percent or 100 percent of their power from renewable sources. Estimates are that for the average WPL residential customer, a 25 percent commitment will raise the monthly electric bill by about $4.

It used to cost utilities considerably more to provide alternative energy sources but the price has come down in recent years. For MGE, for example, green pricing was an extra 3.33 cents per kilowatt hour nearly a decade ago when the program began, Bollom said. Now it is 1 cent per kilowatt hour.

RENEW 's Blume said costs may inch up again because of the high global demand for wind turbines, which has created a shortage of supply. "Also, the weak U.S. dollar hurts because many of the components come from Europe, " he said.

The state Public Service Commission thinks Wisconsin utilities ' green pricing programs are proving to be successful, and are still in the early stages.

"The more that sign up, the better, " Le Monds said. "Any time we can get people reducing the carbon footprint and reducing greenhouse gases, the better. "