Consumers trading in gas guzzlers for plug-in hybrid and electric vehicles may find fewer places for free juice, as cities such as Pleasant Hill and Martinez make motorists pay to use public charging stations.
But industry experts don't expect the fees -- a mere fraction of the cost of a gallon of gas -- to put the brakes on the growing demand for electric cars.
Initially, cities across the country offered free use of their charging stations, but more are moving toward a pay model to recoup maintenance and electricity costs, said Munni Krishna, special projects coordinator for 511 Contra Costa, which gives cities grants to buy vehicle charging systems.
"None of our cities are using it as a revenue generation measure," Krishna said. "They're being fair to consumers to charge for electricity and then a little more for overhead costs."
About five years ago, Pleasant Hill installed electric car charging stations at the City Hall parking lot, the parking garage in the downtown shopping center and the city vehicle parking lot. The stations have logged about 5,000 sessions -- nearly half of those in the past year -- and charged 20 megawatts of electricity.
By the end of June, Pleasant Hill plans to replace the charging stations with a model that can charge two vehicles at the same time, and to put an additional station in the parking garage. Once the new equipment is in, the city will charge 20 cents per kilowatt hour and limit charging sessions to three hours. The current average charge of 4.7 kilowatt hours per session would cost 94 cents.
"The city has provided these stations free of charge for the past 4 1/2 years and we do want to recover our costs, but we don't want to impose a burdensome fee on the user," said spokesman Martin Nelis.
"In essence, we want to encourage more plug-in electric vehicles to use these stations, we want to give more access to the charging stations and encourage people to visit our downtown."
In March, Martinez began charging $1 per hour and limited sessions to four hours at its two downtown charging stations. The third charger, at the Amtrak station, was vandalized last year and no longer works.
The new policy has led to greater turnover.
"People would squat in these stations and they'd stay there all day," said Michael Chandler, senior management analyst for Martinez. "Now we're seeing more people have an opportunity to get a charge. They're only staying as long as they need and that was the intent."
Funding for 511 Contra Costa's electric vehicle charging program comes from the Bay Area Air Quality Management District and a half-cent sales tax in Contra Costa County. Since 2009, the organization has partially funded a total of 28 charging stations installed in Martinez, Pleasant Hill, Walnut Creek, Brentwood, Pittsburg and Contra Costa Centre.
These Contra Costa cities are among the 216 municipalities nationwide on Coulomb Technologies' ChargePoint network, 28 percent of which charge motorists a fee, according to Krishna.
Sales of plug-in electric and hybrid vehicles surged last year and there are nearly 200,000 on the road today, according to the Electric Drive Transportation Association, an industry group. About 40 percent of plug-in vehicles sold nationwide were bought in California, according to the California Center for Sustainable Energy.
Fees may inadvertently boost sales of electric vehicles by reducing demand for charging stations, said Eileen Tutt, executive director of the California Electric Transportation Coalition, which includes utility companies and automakers.
"The bottom line is, when something is free you will use it even if you don't need it, even if it's less convenient," Tutt said. "My sense is, if you really want to make these chargers more available given the limited build-out right now, then charge a small fee -- what it costs -- and you'll find that people will plug in when they need to."
For now, some cities are holding the line on charging people to power up their cars.
The seven electric vehicle charging stations in Walnut Creek remain free, although motorists must pay the 50 cents per hour rate when they use the ones in the city's downtown parking garages.
"The trend is definitely up and we see most of the stations being utilized a good part of the day either by Teslas or Nissan Leafs or Chevy Volts," said Matt Huffaker, assistant to the city manager.
Lisa P. White covers Concord and Pleasant Hill. Contact her at 925-943-8011. Follow her at Twitter.com/lisa_p_white.