The Tesla Roadster promised us the future. A fully electric sports car capable of giving you all the thrills of motoring with non of the environmental drawbacks. Now that they’ve been on the road for a while owners are coming forth with the real cost to own one of these vehicles.

While he describes his earlier reports, when he was part of Tesla Motors, as “naïve,” Martin Eberhard recently amended his comments after putting more than 1,000 miles on his personal Tesla Roadster. Here is what he had to say:

“My first (naïve) comments while at Tesla were between 1.5 cents and two cents per mile, if I recall correctly,” wrote Eberhard. “These were just based on the lowest-tier, off-peak rate. I didn’t take into account the impact of domestic consumption, usage that pushes you into higher tiers or all the taxes and meter charges. I also wanted to know if Tesla’s current claim of three cents per mile is realistic. For my house, it turns out to be pretty close at about 3.6 cents per mile.”

Eberhard has become sort of the unofficial Tesla Motors watchdog ever since he was from the electric-car company. He also blogs about the car’s ease of use. “It is really easy to plug in my car every day,” he notes. “It takes about five seconds to plug in, five seconds to unplug.”

So in the end the answer is yeah, it is way more economical than fossil fuels. At 3.6 cents a mile, it’s like almost 5 times more economical. Seems like the a real alternative to a complex problem. Let’s just see if they plan on making one that isn’t $80,000. Than maybe it can peak the interest of regular folks. That would be a real step forward.