Thesolarindustry is booming, boasting growth of more than 40 percent each year and some $30 billion in sales last year, according to Photon International.

Yet the technology has only delivered a morsel of the energy the United States uses each year.

According to a study released this week by research firm Clean Edge and nonprofit Co-Op America, solar generated less than 1 percent of the country's total electricity last year.

The study projects that percentage will grow in a big way, from 1.3 gigawatts in 2007 to 255.6 gigawatts in 2025, at which time solar will make up 10 percent of the country's total electricity.

But for that to happen, more utilities will need to turn to the renewable energy, according to the research.

U.S. utilities already have shown some interest in solar, especially concentrating solar-thermal plants, which use the sun's heat instead of light to make electricity.

California utility Pacific Gas and Electric Co. said last week it had inked a deal to buy power from a hybrid project that will combine solar-thermal and biofuel technology to make electricity (see PG&E to Get Power from Solar-Biofuel Hybrid Project). Among other projects, the utility also plans to buy up to 900 megawatts of solar-thermal power fromBrightSource Energy.

In March, Southern California Edison announced a 250-megawatt project that would put solar panels on commercial rooftops, and earlier this month signed a contract to buy 245 megawatts of solar-thermal power from eSolar.

Building all the infrastructure needed to produce 10 percent of the country's electricity also would require plenty of money -- up to $560 billion between now and 2025, according to the study.

But the study concluded that the investment of up to $33 billion annually is possible.

The Edison Electric Institute estimates that the U.S. electric utility industry last year spent more than $70 billion on new power plants, transmission and distribution.