Solar panels are becoming increasingly popular in Napa County, as they are installed on rooftops everywhere from the newest subdivisions of American Canyon to Calistoga wineries.

Napa County is solar friendly, but on average Napa County residents pay higher permitting fees to install solar panels than other Northern California property owners.

The county produces more solar energy per capita than nine other Bay Area counties, according to the Northern California Solar Association, a group of solar advocates. Yet a survey of 131 jurisdictions in 13 Northern California counties by the Sierra Club found that Yountville, Calistoga and the city of Napa charge on average $141 to $324 more than other Bay Area jurisdictions to install an average-sized residential system.

While St. Helena has joined other Bay Area cities that no longer charge a fee to install a solar panel system, Napa charges the most -- $768, though that may change.

Napa City Councilwoman Juliana Inman said the city is in the early stages of drafting a green building ordinance that would encourage a list of environmentally friendly practices, including the use of solar panels. The new regulations might lower the cost of getting a permit to install solar panels.

The city's fee could decrease to $300, said Stephen Jensen, chief building official, who noted that all the city's permit fees are being reviewed. The new price would reflect the cost of doing a one-hour inspection and a one-hour plan check instead of charging by the value of the property improvement.

The city doesn't want the fees to be "a disincentive," said Inman.

Yountville charges $585 to install a 3 kilowatt-hour system, according to the survey published by the Loma Prieta, San Francisco Bay and Redwood chapters of the Sierra Club.

Yountville's fee is based upon the value of the project, Bob Tiernan, the city's interim city manager, wrote in a recent e-mail.

Meanwhile, state and federal officials are working to make solar affordable.

California has decided to spend $3.1 billion in incentives over the next decade to spur the installation of solar panels on a million roofs in the state. In addition, state and federal rebates reduce the cost of a solar panel system by as much as 25 percent.

But the Sierra Club's solar advocate Kurt Newick, co-author of the Sierra Club survey, wants cities and counties to charge one flat fee to encourage more people to go green.

Fees should be no more than $300 to review the plans of a 3 kwh residential system, said Newick, who applauds the city of Napa for preparing to lower fees.

As of mid-July, out of 131 jurisdictions surveyed by the Sierra Club, 84 charged less than $300, 10 charged fees of $600 or more; 14 charged nothing. The average fee was $282.

Bernadette Del Chiaro, clean energy advocate for Environment California, a solar advocacy group, said there are efforts statewide to make solar power mainstream. Cities and counties should only charge to process the application, she said.

There is no real justification for charging $1,500, she said.

Michael Leyba, sales manager at SPG Solar, a company based in San Rafael, said one issue is the slow turnaround in unincorporated Napa County.

Napa County charges $433, but requires engineering reports that can add an extra $700 to the bill and delay the installation by as long as four weeks, Leyba said, adding the fees and the red tape have discouraged potential customers.

According to Rick Turley, general manager for Advanced Alternative Energy Solutions, the average residential system can cost between $22,500 and $37,500.

In the meantime, Napa residents and businesses continue to embrace solar power.

On Monday, Cuvaison Estate Wines fired up a solar power system to handle nearly all of the winery's energy needs. In a prepared statement, Cuvaison President Jay Schuppert said the move would save the winery $51,000 in annual electricity costs. He said his winery and the whole industry have moved toward solar energy as concerns over climate change have grown.

"After talking to other wineries that have gone solar we decided we wanted to be a member of that group," said Schuppert.

Amizetta, a boutique winery in Conn Valley, three months ago inaugurated a 27.7 kilowatt-hour solar power system -- large enough to power nine average homes -- according to Turley, the consultant who sized Amizetta's solar system to generate enough power for a house, a winery and up to five wells in the 40-acre vineyard.

Spencer Clark, Amizetta's owner, said he paid $160,000 to install the solar panel system.

He did it because the price he paid for electricity was "extreme," he said, adding his monthly PG&E bills were $1,500 to $2,000.

He figured, that with the incentives, the system will be paid off in four to five years.

His PG&E bill is now "pretty much zero," he said.

Napa County resident Brad Shurmantine believes he will pay off the solar system for his house and a shed in about 13 years. His 5.1 kwh solar system cost $29,407 after a state rebate of $14,280 and a federal tax credit of $2,000, Shurmantine said.

"I've thought about going solar for many years," he wrote in an e-mail. "The recent unrest in Iraq and the Middle East is what essentially pushed me over the edge."

The system has worked without a glitch, wrote Shurmantine.

His annual PG&E bill went from $2,560 to $272 last year.