As we celebrate Earth Day for 2012, it's impossible not to notice that electric cars, partly championed by the environmental movement, are becoming available with more on the horizon.

While they've come in for a lot of criticism for their high prices, short driving range, and government subsidies, we've found they can cost less than half as much to operate as gas-powered cars. They use far less energy, giving them the energy equivalent of about 100 mpg.

The cars that have come out in the last year, the Nissan Leaf, the Mitsubishi i, and the Ford Focus EV, are short-range electric cars, designed for commuting within about 40 miles of their owners' homes. That's because there's no widespread network of public electric-car charging stations to refill the cars if they drove farther than that. (Forget, for a moment, plug-in hybrid, or range-extended electric cars, which travel farther on gas.) Electric cars today are expected to charge in owners' garages. And as commuters, they're largely relegated to second-car status.

But there's another, nascent vision for electric cars that's beginning to gain traction: the full-function electric car with a range-on batteries alone-roughly equivalent to gas cars'. The vision has largely been promoted by Tesla and its relentless and ambitious founder Elon Musk.

For that vision to work it will require that a network of charging stations that can "refuel" a long-range electric car in not much more time than it takes to fuel a gas car today.

Enter a new series of startup companies that have sprung up to begin building the infrastructure to charge these longer range electric cars. Most are working in the cities with the highest concentrations of electric cars, building largely Level 2 (240-volt) chargers, to help extend the reach of today's electric cars. But that can still take several hours.

So some of the companies are pairing up with retailers to install so-called Level 3 "fast chargers," of up to 480 volts. This was made possible late last year by the adoption of a standard plug for these fast chargers, called the J1772 "Combo-coupler." The problem: Existing electric cars capable of accepting such a fast charge use two different kinds of plugs one on the Nissan Leaf, and yet a different one on the Tesla Roadster. No car yet uses the new plug.

This week we got a visit from one entrepreneur, Bruce Brimacombe, who is trying to get a company, GoE3 off the ground that will supply chargers at a series of businesses that can easily charge all these types of cars with minimal modification.

GoE3 plans to concentrate on building chargers along Interstates across the middle of the country - precisely where electric cars today pretty much can't go. He plans to connect electric-car communities in the East and West so believers can drive cross-country without running out of juice. The concept is similar to that of Israeli/Californian startup Better Place whose network of public charging is already up and running in Israel and Denmark and similar plans for Australia and other regions are in the works.

This addresses a perceived problem among electric vehicle owners in California that many of the state's 1,200 plus charging stations use older charging technology that's incompatible with their cars, and so are useless.

Other companies, such as BlueMobility and Blink are also beginning to adopt the new plug standard and offer multiple plugs.

All these networks will be connected to mobile-phone applications to help drivers find and reserve available chargers.

As electric car and battery prices come down, it will be interesting to see whether longer-range electric cars will win over more buyers. As the cars begin to hit the road, we'll be there to let you know how well they live up to their claims.

For more on alternative fuels, see our special section.