DETROIT – General Motors Corp. finds a seemingly unlikely advocate in its corner, documentary film maker Chris Paine, who roasted the auto maker two years ago for giving up on the EV1 electric vehicle.

The auto maker also reveals a change to the operating system on the ’11 production Chevrolet Volt, switching from a concept that uses an internal-combustion engine to continuously recharge its lithium-ion battery to one that powers an onboard generator that sends electricity to the drive wheels.

Whichever technology path GM chooses, Paine considers the Volt the correct approach to electrification of the automobile.

Paine, who directed the 2006 film, “Who Killed the Electric Car?,” spoke with Ward’s after participating in a panel discussion on the future of the automobile at GM’s recent centennial celebration.

The film took GM to task for discontinuing the EV1 and re-collecting the leased vehicles from protesting drivers. Paine says he attended the centennial event at GM headquarters in Detroit by invitation.

“I like (the Volt) concept better than the (Toyota) Prius, personally, because I know how much fun it is to drive with an electric motor,” says Paine, who soon will release a sequel documentary called, “Revenge of the Electric Car.”

“(The Volt) is so smooth and fast, and you can (choose) to not use any petroleum,” he says of the car’s technology. “I don’t have that option in my Prius. I always have to fill that sucker up. So I think it’s the better approach.

“My vote is for anything that lets you drive electric and plug it in,” he says.

GM calls the Volt an extended-range electric vehicle (EREV) and has sought to distinguish it from the plug-in hybrid-electric-vehicle segment occupied by the Prius and other upcoming PHEVs, including the Detroit auto maker’s own Saturn Vue PHEV due in 2010.

As with a PHEV, the Volt plugs into a household outlet to recharge its Li-ion battery pack, but its engine never directly powers the wheels, GM says.

Should a driver travel beyond the 40-mile (64-km) all-electric range provided by the battery, the ICE will engage and drive an electric generator that, in turn, provides the electricity to drive the wheels.

By comparison, a PHEV uses a parallel-hybrid system, where the ICE acts as the larger of two power sources to drive the wheels, with assistance from a battery. PHEVs especially rely on the engine during heavy acceleration.

“This is the winning formula,” says GM Vice Chairman Bob Lutz, speaking with journalists after driving the production Volt on stage at the centennial event. “You’ve got fully electric drive most of the time, but thanks to the backup piston engine, you have no range anxiety.”

Rob Peterson, a spokesman for GM, says the previous approach would have eliminated the Volt’s goal of 40 miles of gasoline-free driving, because at some point before the battery reaches the end of its range the ICE would engage to begin a replenishment cycle.

“So the best solution is one that gets you to your destination without ever replenishing the battery,” he says. That way drivers take as much electricity from the grid as possible when they plug in for a recharge.

It’s cheaper, Peterson says, noting the Volt will cost $0.02 per mile when driven electrically vs. $0.12 per mile using gasoline at $3.60 per gallon for a comparably sized vehicle with a conventional powertrain.

And it achieves the goal of 40 miles of all-electric, emissions-free driving, he notes. The distance accommodates the driving habits of 76% of Americans, who travel 40 miles or less per day.

Paul Scott, co-founder of Plug-in America, a coalition of electric-vehicle users, dismisses the Volt’s change as merely evolutionary.

“It’s a small technical change,” he says. “This isn’t rocket science, although it is science and engineering at a very high level.”

In fact, Scott’s main concern with a production version of the Volt, which GM promises at Chevy dealers by November 2010, is whether it will match EV offerings from Toyota Motor Corp. and Honda Motor Co. Ltd. due to market in the same timeframe.

Honda and Toyota are ready to go, and you know how good those guys are,” says Scott, a Prius owner. “American auto makers have been ludicrously pathetic” by comparison.

“I really want to see them make a good product,” he says of the Volt and newly announced EV plans from Chrysler LLC. “This planned obsolescence has been coming from executives wanting to sell consumers another car in three years, not from the engineers. Our engineers are as good as (the Japanese).”

Film maker Paine also views time-to-market as a critical element to the Volt’s success. “Get it to market,” he says. “And the secondary hurdle is to educate the public and get them excited about it.

“People are ready for it, and there already is pent-up demand,” he says, pointing to an unofficial list of 30,000 Volt enthusiasts who want the car.

Perhaps the greatest hurdle, Paine says, will involve GM exchanging a culture based on the ICE to one that emphasizes the electric motor.

“It’s a real transition that’s a fundamental shift in what the company is,” he says. “I don’t think there’s been a bigger change in the auto industry in the last…well, ever.”

Says Lutz: “Given the realities of the energy situation, our dependence on foreign oil and the fact that oil is a finite resource, I would say the electrification of the automobile is a foregone conclusion, an absolute foregone conclusion.”

GM’s product czar claims the auto maker has a 3-year head start over other auto makers in pure electric cars because of its EV1 experience.

“As we face these mandates on CO2 (carbon-dioxide emissions) and petrol consumption,” he says, “to try and get there by conventional means gets more and more expensive, as we’re more and more adopting highly marginal and very costly solutions just to squeeze out another tenth of a mile per gallon.

“Whereas with (the Volt), we are in the same cost range.”

Lutz thinks the Volt will recharge other GM divisions, as well, and prove to consumers the company can stand toe-to-toe with foreign auto makers on the technology front.

“One of the reasons many Americans today don’t consider GM is they don’t consider us a leader in energy-saving technologies,” he says. “I think with one fell swoop the advent of the Volt will erase that. The question is how soon people will become aware of it. But we’re sensing a growing awareness now.”

Lutz cites The New York Times crossword puzzle, which he says recently used “a 4-letter word for a highly fuel-efficient vehicle from General Motors” as a clue.

“When The New York Times crossword puzzle starts picking up (the) Chevrolet Volt, you know we’re breaking through the consciousness barrier.”

jamend@wardsauto.com