Sarah Preble says it didn’t take long for her and her husband to get over the anxiety of driving their electric Nissan Leaf far from their Manoa home and the security of the charging station in their garage.

Starting out with relatively short trips, Sarah and Duane Preble gradually added more distance to their jaunts. But even their longer trips were well within the 100-mile advertised range of the Leaf, the first mass-marketed electric vehicle in Hawaii. On their longest drive the battery still had about 30 miles to spare.

"We haven’t driven to our son’s house in Kahaluu yet, but neither one of us is worried," Sarah Preble said.

The Prebles, who also have "zeroed out" their electric bill with the installation of photovoltaic panels on their roof, are early adopters when it comes to green technology.

To get the wider driving public to embrace electric vehicles, however, officials will have to deal with the problem of "range anxiety" that is fueled by the lack of charging stations across Hawaii as well as the mainland. Only after that problem is solved will electric cars be able to get past their novelty status and become viable competitors to gasoline-powered vehicles, EV supporters say.

Toward that end the state Department of Business, Economic Development and Tourism launched a $2.6 million program in March using federal funds to put up more than 450 public charge spots across the state by next spring. The City and County of Honolulu is using $400,000 of the grant to put charging stations in public parking lots and to develop on online portal to let citizens apply for charging station building permits.

DBEDT is following the lead of President Barack Obama, who has set a goal of putting a million plug-in vehicles on the road by 2015. The state also needs electric cars to help it meet the ambitious targets in the Hawaii Clean Energy Initiative.

The two companies that landed the main DBEDT contracts for the job — AeroVironment Inc. and Better Place — say they are in preliminary discussions with a range of potential "hosts" for the charging stations, including shopping malls, hospitals, hotels and office buildings.

AeroVironment, which won a $820,000 contract to provide 320 charging stations across all major islands, says it will provide installation quotes to retailers and other potential hosts over the next 30 days and begin installing charge spots in 45 days.

"People have been very positive about being able to participate," said Kirsten Hensel, vice president of EV solutions for AeroVironment. "Hawaii is uniquely positioned to benefit from this. The commitment to energy independence in Hawaii is reflected in the level of interest we’ve received on this project."

Both AeroVironment and Better Place are evaluating potential charge spots, taking into consideration things like distance from an electricity source, the expense associated with a potential site and its proximity to other charge sites. AeroVironment has completed about 70 to 100 assessments, Hensel said.

Better Place recently launched a public relations campaign to get the word out "that this is a tremendous opportunity to be a part of the electric vehicle charging infrastructure," said Brian Goldstein, director of Better Place’s Hawaii operations.

"Our goal is to have these charging stations installed in a manner that makes the most sense and provides the most value to the state," Goldstein said. "We don’t want to have locations in only the highest population areas. We want to put locations in remote areas as well," said Goldstein, whose company is under contract to install 130 charge spots.

Better Place, which recently installed five charging stations at the Sheraton Waikiki Hotel and five at Hawaiian Electric Co. facilities, hopes to have locations for all its charge spots locked up by the end of this summer, he said. The company is still looking for partners and is encouraging any businesses that are interested to call Better Place, Goldstein added.

Landowners who come on board during this first round of installations will be able to do so at a lower cost because the federal grant is subsidizing some of the cost, he said.

The "Level 2" charge spots being installed by the two companies are fed by a 220-volt circuit using an industry standard SAE J1772 plug, the same used in a home charging station. The devices can provide a full charge for a Nissan Leaf — the equivalent of about 24 kilowatt-hours of electricity — in about seven to eight hours, according to Nissan’s website. Neither company has immediate plans to install any 480-volt Level 3 stations capable of delivering a full charge in 30 minutes.

Better Place expects the public stations will be used mostly for supplemental charging. It is anticipated that electric vehicle owners will do about 90 percent of their charging at home or wherever their car is parked in the evening, Goldstein said.

Better Place is working with property owners hosting the charge spots to make the service free for the first year in order to promote the use of electric cars.

"When you drive around and see charging stations, the people who are not early adopters will realize that electric cars are a safe choice," Goldstein said.

Customers using Better Place stations will have to sign up for an account that features a swipe card with a radio frequency identification tag that allows the company to keep track of who is using its system and how much electricity they’re using.

Better Place plans to eventually implement a payment model offering customers flat monthly rates similar to what mobile phone companies use, he said.