The era of the electric auto may finally have eased out of the driveway.

Hundreds of people in several states are test driving electric MINI Coopers And a preproduction version of the Chevy Volt hit the streets earlier this week, weeks ahead of schedule. But being an early adopter isn’t cheap.

GM's Fastlane Blog features a post by Chevrolet Volt Vehicle Chief Engineer Andrew Farah about his experience driving the Volt for a few laps around the company's Technical Center campus in Warren, Mich. Besides the expected glowing review of the car, Farah reports that Chevy is making a few Volts per week now and plans to have about 80 preproduction vehicles built by October. The production Volt isn't due until 2011.

Readers of Farah's blog post were concerned with how much the Volt was going to set them back. Citing a rumored cost of more than $40,000, reader Laszlo Steiner commented, "The main value of the car would be for those few rich people wanting to make an environmental statement as opposed to those wanting or needing practical transportation." Another reader questioned how much a new battery would cost and pointed out that some states charge as much as $3,000 for a hazardous disposal fee to get rid of the old battery.

Farah tried to address some of these concerns Thursday in a live Internet chat. When asked whether Chevy could reduce the price of the Volt by 25 percent and extend the life of the battery over the next six to eight years, Farah responded that his company has a good chance of meeting those goals. "Six to eight years is a long time when working with emerging technologies that are being used in the electrification of the automobile," he wrote, adding that "early public acceptance" is critical when driving down costs, "so it is a bit of a chicken and egg issue."

BMW is taking its MINI Cooper E straight to the people (450 people living in California, New Jersey and New York State, anyway). These test drivers (chosen from a pool of applicants) are getting behind the wheel of a preproduction version, the actual MINI E won't debut until 2012.

Lyle Dennis, editor in chief of the site
(published by High Gear Media), gave his MINI E mostly high marks. He describes the car as a standard MINI Cooper that's been modified, with a 500-pound lithium ion battery pack that replaces the back seat. He calls the car "extremely fast and exciting to drive," while noting there's "a slight delay in torque" when taking off from a complete stop. He also describes how the car's regenerative braking system begins to slow the car as soon as the driver's foot is lifted from the accelerator, making it often unnecessary to actually use the brake pedal.

All of this technology comes at a cost, however. Dennis and the other test drivers are paying $850 per month to lease the cars from BMW. The standard gas-powered Cooper hardtop sells for about $20,000.

Image: The Chevrolet Volt engineering development mule vehicle at the General Motors Tech Center in Warren, Mich., Monday, May 18, 2009. (Photo by John F. Martin for General Motors, via Flickr)