Solar energy in California is blazing its way from rare toward realistic -- with virtually everyone in the state picking up the bill.

Rooftop solar systems have emerged from their niche as backwoods electricity, best suited to spots too remote for power lines. Energy from the sun is becoming increasingly popular in cities and suburbs, on homes and businesses already connected to the electric grid.

The amount of electricity generated nationwide by these scattered, "grid connected" solar installations leaped from 12 megawatts in 2001 to 22 megawatts in 2002, said Paul Maycock, president of PV Energy Systems, a consulting company that tracks the industry. California, home to the source of about half those megawatts in 2001, generated nearly three-fourths of them by 2002, he said.

"This is the biggest growth of any sector in the history of photovoltaics," Maycock said.

The boom also has refocused interest on whether money flowing to solar is being spent wisely

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The solar energy system, background, at the Penryn home of
Steve and Tanda Ainsworth generates about 400 kilowatt-hours of power a month.
Their annual electricity bill has dropped from $1,400 to less than $100.

"We're massively oversubsidizing its use and we're undersubsidizing its development," spending too little on cutting-edge research that could lower solar's cost, said Severin Borenstein, director of the University of California Energy Institute.

The growth of photovoltaics, or PV -- solar cells that make electricity from the sun's light -- touches just about everyone, whether or not they use solar power.

With each new system that goes up on someone's roof, the air is fractionally cleaner because smaller amounts of polluting fuels need to be burned to generate electricity. The fossil fuel supply is a tiny bit less strained, because more people are using a renewable energy source.

But electricity bills are slightly higher, because virtually all consumers in the state kick in, through their power bills, to various special funds that help subsidize solar power. And state revenues inch lower, because people who install solar power get a partial tax credit.

For all that, what Californians are buying is a growing stream of power from one of the costliest -- and just plain snazziest -- ways to generate electricity.

"PV is kind of charismatic. Everybody wants to just show the good side," said Steve Ainsworth, a civil engineer who has navigated a labyrinth of rules and rates to find the circumstances under which solar power can pay off for consumers.

New rooftop systems are going up so fast that the state Energy Commission predicts it could run through five years of subsidies in the next two years.

Solar energy is dominating a Public Utilities Commission program that subsidizes renewable and extra-clean energy for big power users, outpacing all expectations and eating up some funds originally set aside for fuel cells.

Los Angeles' public utility has stopped taking new applications for residential or commercial solar, partly because it was swamped with applications after letting big customers collect rebates from its own program and one run by an overlapping gas utility.

The Sacramento Municipal Utility District's waiting list for household solar, while down from past heights, is still too long to be covered this year by the money in SMUD's scaled-back program.

Environmental groups and a state senator are pushing legislation to require solar roofs on many, perhaps most, of new homes built in California.

And radio ads are pitching solar power as a way to reduce dependence on foreign oil, improve air quality and save money.

For many people, though, solar savings can be elusive.

"There's a lot of hype," said Ainsworth. "You have to really sift through all the numbers."

Many vendors sell household solar power by telling buyers that after eight or 10 years, the savings on their electric bills will pay for the cost of a system that can run $8,000 or more, even after rebates. SMUD calculates that its residential solar purchasers break even after eight to 12 years. The state Energy Commission figures an average residential system will pay for itself, with rebates, in 10 years and probably will have a useful life of 20 to 30 years.

In two special conditions, though, going solar can pay for itself right away, given current utility rates, rebates and tax credits, said Ainsworth.

A household that uses a lot of electricity in the higher-priced tiers of Pacific Gas and Electric Co. rates, and gets a PV system just large enough to displace only that extra-costly power usage, can break even or come out ahead, he figures. So can people willing to switch onto PG&E's special "time of use" rates, and structure their lives to use very little power between noon and 6 p.m. on weekdays for half the year.

For everyone else, household solar power needs to be a long-term proposition -- or perhaps a philosophical stand.

Businesses and government entities buying solar setups 15 times bigger than the average household system face different equations. In regions where they can collect subsidies from multiple programs, they sometimes come out ahead right away.

Without any rebates or tax credits, electricity from rooftop solar systems can cost more than 30 cents per kilowatt-hour to produce, said Steve Hester, technical director of the Solar Electric Power Association.

Solar is many years away from being able to compete, unaided, with central power plants that produce at 3 cents to 5 cents a kilowatt-hour, he said.

But solar has other values. It's clean, it can be scattered through neighborhoods where it is used, and it can help enhance grid stability by producing the most energy at peak hours when electricity is most in demand, he said.

Hester thinks the biggest challenge solar power faces today is not technological, but psychological. His association wants to sell the American public on the idea that clean energy is worth paying more for, just like bottled water or a fancy car.

California is one of the spots in the country where that notion could be a relatively easy sell.

Today, 85 percent of all solar power generated in the United States is produced in California, according to Platts Research and Consulting.

Platts predicts that photovoltaic generation in California will increase nearly sixfold in the next 12 years, from an estimated 40 megawatts to 224 megawatts. Even though other states, too, are subsidizing more solar, California still will produce about 60 percent of all U.S.-based solar power in 2015, Platts forecasts.

Some advocates of solar power fear that perhaps too much money is flowing in ways that have not been well thought out.

Subsidies can backfire, tempting vendors to keep their prices high enough to capture the maximum subsidy offered, and propping up products that couldn't stand on their own. They can be so popular that they run out early, stranding consumers or vendors.

"The subsidy tells people that you have extra money to put onto your system cost," said Steve Coonen, vice president of Atlantis Energy, a Sacramento company that makes solar roof tiles. "It artificially inflates price, but it also promotes volume," and in time, volume could drive prices down.

Even some of its strongest supporters believe that solar power needs to outgrow subsidies.

"I'm a huge fan of solar, but we have to be realistic," said Susan Patterson, president of the SMUD board, which plans to ask customers this year to help decide how much of their electricity rates should be devoted to solar.

"Eventually, the money is going to run out and it's going to have to stand on its own," she said.

Solar power by the numbers

$125 million
Amount paid each year by customers of Pacific Gas and Electric Co., Southern California Edison, Southern California Gas and San Diego Gas and Electric Co. to fund a program that subsidizes solar power, wind power, fuel cells and extra-clean microturbines for large power users.

$30 million
Amount paid each year by electricity customers of PG&E, Southern California Edison and San Diego Gas and Electric to subsidize solar power for households and small businesses. The five-year program is administered by the state Energy Commission.

$3.3 million
What customers of the Sacramento Municipal Utility District are expected to pay in 2003 to support solar power.

$2.5 million
Amount knocked off state income tax bills of about 1,500 individuals and three corporations in 2001 because they installed solar systems and took the 15 percent state solar tax credit.

150,000 pounds
Amount of nitrogen oxides, a key ingredient of smog, that is kept out of the air every year because of solar power in California, according to Energy Commission estimates.