Sonoma County's "Electric Trail" continues to grow, though parts of the network of charging stations for electric vehicles have yet to open nearly two years after being installed.

The purchase of 12 new charging stations in the north county, including Guerneville, Cloverdale and Healdsburg, using $150,000 in grant money, was authorized Tuesday by the Sonoma County Board of Supervisors.

The move follows a similar vote in January for 18 charging stations for the county's southern area, including Rohnert Park, Cotati and Petaluma.

But for all the progress, aspects of the trail have languished.

The city of Santa Rosa installed 13 charging stations in the summer of 2010. Nearly two years later, they remain unused, in part as a consequence of back-and-forth negotiations with the vendor on how to charge users for electricity.

Unlike other local jurisdictions, Santa Rosa plans to charge drivers for electricity, which has bogged down the process.

Steve Kroeck, the city's deputy director of field services, said he hopes to soon bring a final agreement to the City Council, allowing the stations to become operational by the start of the fiscal year.

"July 1st, that's my goal," he said.

Still, the expanding infrastructure seems likely to enhance Sonoma County's reputation for embracing electric vehicles, especially as another looming grant program may add still more charging stations across the county.

For Petaluma Mayor David Glass, joining the county effort was an easy decision, one that will allow Petaluma to appeal to a new breed of green-minded tourists while lending support to a major local business.

The city's Northbay Nissan dealership is a leader in electric vehicle sales, topping the country in sales of the electric Leaf model last year.

The benefits, Glass said, far outweigh the cost, especially with outside grants covering equipment and installation.

"When you look at the total picture, it's a statement that Petaluma is right to make," he said. "It's something that puts us on the map."

The three 220-volt stations provided through the grant will cost Petaluma an estimated $4,800-a-year for electricity, which the city will cover rather than pass on to drivers.

Petaluma plans to install a 440-volt fast-charger that will be able to charge cars in as little as half an hour compared to the four to eight hours with the 220-volt systems.

The fast charger will cost the city an estimated $1,590 a year in electricity.

Nationally, electric cars have struggled. Earlier this month, Chevy temporarily idled production of its Volt line amid slow sales.

But California is making a strong push to expand their growth. Last week, Gov. Jerry Brown announced he would use a $120 million legal settlement to fund a statewide network of chargers.

And Sonoma County has a particular interest in the vehicles, said Dave Head, Sonoma County's fleet manager.

"The Bay Area is a hot bed of electric vehicles for the nation," he said. "And Sonoma County is one of the most active regions of the Bay Area."

Still, locals aren't the ones likely to most need the new stations. Many local drivers of electric vehicles do their charging at home -- and won't necessarily need such chargers, said Alan Soule, president of the North Bay Electric Auto Association.

The new stations are likely to draw in outsiders and visitors who can expand their range using the chargers, said Soule, who recently drove to Palm Springs in his electric Tesla, planning his route around charging stations along the way.

Additionally, new chargers have been installed -- or soon will be -- at businesses including local Walgreens as well as malls like Petaluma Village Premium Outlets and Santa Rosa Plaza.

You can reach Staff Writer

Sam Scott at 521-5431 or at sam.scott@pressdemocrat.com.