Despite the hoopla over renewable energy - media chatter, government rebates, neighbors who "go green" - the nuts and bolts of installing more Earth-friendly power sources often get stuck.

San Diego County, for example, is wrestling with how to handle applications for using residential wind turbines. Critics say the approval process is confusing and drawn-out enough to discourage investment in green power, just as companies are moving to fill the home-windmill niche.

Similar difficulties are popping up nationwide as regulators try to accommodate renewable-energy projects while protecting property owners' backyard views, minimizing noise and addressing safety concerns.

"People are definitely encountering permitting problems as one of the factors slowing down the work and making the process a lot more difficult," said Dariush Shirmohammadi, an adviser for the California Wind Energy Association. "It seems to be an issue for all sizes of renewables . . . and is a major concern for most developers."

San Diego County isn't a state leader in wind-energy production, but wind is considered an important source of the region's future electricity supply. Although most wind power in the area comes from commercial-scale turbines, more residents want to install small systems that have become less expensive thanks to technological improvements and governmental incentives.

Nationally, wind-energy production has risen in the past decade.

Last year, enough wind-capturing capacity was installed nationwide to serve more than 2 million homes. A recent federal report said wind could generate 20 percent of the nation's electricity by 2030.

Advocates of wind power said its full potential can't be harnessed when it's snarled by bureaucracy.

Obtaining permits for home-based turbines can be tough in parts of the country, and California "is definitely regarded as one the more difficult," said Jacob Susman, CEO of OwnEnergy, a wind-power company in New York.

Impediments include the lack of consistent standards from county to county and the cost of permits, which can double the price of a residential turbine, said Case van Dam from the California Wind Energy Collaborative at the University of California Davis.

As San Diego County's land-use planners try to refine the rules for residential turbines, companies that make them and people who want to use them can be left twisting in the breeze.

"We started in San Diego County because of the favorable zoning law," said Bob Hayes of Prevailing Wind Power in Redondo Beach. "San Diego was shaping up to become the Silicon Valley of small wind."

But county officials have become too restrictive with home turbines, Hayes said. Such systems can generate up to 500 kilowatts of electricity - roughly enough to power a small home. Hayes estimated that there are 20 residential windmills in the region.

County regulators said they support alternative energy but need to make sure the equipment doesn't endanger the neighborhood. They are working to revise noise, safety and other standards for companies manufacturing residential turbines.

"Our Board of Supervisors is very green-project friendly," said Darren Gretler, the building division chief. "We want to do everything we can to make it more efficient for people to make energy-efficient products."

The region's potential for wind power is greatest in and around the Laguna Mountains. There are very few spots available for large-scale turbine projects, but opportunities for residential systems exist in Alpine, Ramona and other communities east of San Diego, said Ryan Amador, a manager at the nonprofit California Center for Sustainable Energy in Kearny Mesa.

Amador often receives phone calls from homeowners who hope to use small wind turbines but wonder if it's too challenging to navigate the county's evolving criteria.

"I wouldn't say necessarily that it's the county of San Diego's fault," said Amador, whose center is looking at how to help residents and regulators simplify the permit process. "(Renewable power sources) are emerging industries. . . . They are not necessarily covered in the old county general plan."

Red tape has stymied Gil Riegler and Nancy Kolbert, who bought a home turbine last year but don't have permission to turn it on.

"This was supposed to be in and working quite a while ago - months ago," said Kolbert, who operates a camel dairy on 34 acres the couple own in the Ballena Valley outside Ramona.

"It's up. It's beautiful. It's unobtrusive. To me, it stands as a beacon of forward thinking. I love it and I hope that the county will kind of chill out."

Two years ago, county planners allowed a handful of backcountry residents to install Skystream 3.7s, home turbines that feature a 12-foot rotor atop a pole up to 50 feet tall. Last year, they approved nine more.

After the initial group was permitted, sales representatives for the Skystream continued marketing their product even though county officials were waiting to see how the first systems performed.

Within a few months, the county received a noise complaint and put the brakes on new approvals.

Planners began requiring that sound checks be conducted from the applicants' property lines rather than the nearest dwellings, which in some cases raised the decibel level to unacceptable standards. The noise limit is 50 decibels during daytime - quieter than some air conditioners and roughly equal to light traffic in a peaceful neighborhood - and 45 at night.

County regulators also sought certification from Underwriters Laboratories, the international product-safety analyst, that the wind turbines were designed and manufactured properly.

Hayes complained that Underwriters Laboratories has no formal standard for the Skystream 3.7 and said the California Energy Commission recognizes a different certification issued by Germanisher Lloyd, another certifier.

"For every turbine and permit I'm denied, there are thousands of dollars in incentives that are going to other states," Hayes said.

Gretler said the county would soon start accepting the Underwriters Laboratories outline for certification until the company completes its formal studies.

"The Skystream maker is a trailblazing company, and we're trying to be trailblazers, too," he said. "Together, I think we will make things happen."