This is an experiment, and we hope it is the first of many such exchanges marking this incredible turning point in the history of the automobile. Are we moving to electric vehicles (EVs) and, if so, when? I'm joined in this dialogue by Matthew DeBord, who writes the Shifting Gears blog at Slate's The Big Money. He has written about the auto industry and sustainable mobility for the Washington Post, the Los Angeles Times, and the Huffington Post.

Jim Motavalli: I think President Obama’s announcement of tough new fuel economy standards for cars and trucks—a fleet average of 35.5 mpg by 2016—is a turning point for the auto industry. The age of big SUVs is over, and the future belongs to electric vehicles (EVs). Although hydrogen cars (with electric drive) may be a long-term solution, battery EVs are virtually the currently available “zero-emission” option. I don’t minimize the challenges—range, cost—but I still see 20 percent (and in a best-case scenario, 30 percent) penetration by plug-in hybrids and pure battery EVs by 2020. Eventually, I see full electrification of the auto fleet.

Matthew DeBord: I agree that the new fuel-economy standards, coupled with ongoing creative destruction in Detroit, signal a turning point for the auto industry. However, I don't think we're going to see as much market penetration by plug-in hybrids and EVs. Price is a major issue. For EVs, it will take more than 12 years for truly affordable pure-battery EVs to make up a fifth of the market. We'll get there, but I see the tipping point as sometime in the middle of century. Conveniently, I think this is also when peak oil will become an urgent problem. I'd like to see the carmakers focus aggressively on gas-electric hybrids for their next few product cycles, gradually hybridizing much of their fleets. I want to see diesels come into the mix, as well. In other words, while I think EV development should continue, we should commit to oil, not electricity, as our main transportation energy source for the next 30 years.

Motavalli: But, Matthew, I don’t think we have the luxury of that kind of leisurely timetable. Global warming demands much faster action than that. I think peak oil may have already happened—we’ll only know that in hindsight. These are technology-forcing, world-changing events, and they’ll be aided by worldwide subsidies and incentives. Under normal circumstances, I think your scenario is about right, but these are extraordinary times we live in.

DeBord: So the idea is to push hard for EVs, to get us off oil as much as possible over the next 10-20 years? That's going to require some major technological leaps, as well as massive private and public investment. I'll grant that plug-in hybrids may ramp up pretty quickly, but pure EVs are tougher. There's only one, really, that meets typical range demands right now, and that's the Tesla Roadster, which costs more than $100,000 (and isn't being manufactured on schedule). The electric Smart isn’t versatile enough. The Chevy Volt will only get you 40 miles on the battery. In order to get here there with EVs, we'd have to hugely subsidize the whole thing—and perhaps end up with cars that the consumer won't buy. Meanwhile, we have successful all-gas and gas-electric hybrids that get good mileage with low emissions. So rather than trying to fight global warming with an EV Hail Mary pass, I think we should “hybridize” the road and start dealing with global warming right now.

Motavalli: I don’t want to sound like a hybrid naysayer—I’m a huge supporter—but only pure EVs will get us to zero emissions. I know that it matters where the power comes from, and coal-powered electricity has major emissions associated with it—but the Obama agenda is multi-pronged, and includes both a smarter and a cleaner grid. Yes, I’m all for pushing hard for EVs. And I think the carmakers are getting the message—the as-yet-unnamed 2010 Nissan EV sedan will be a mass-market vehicle, not just for car shows and demonstration projects. I think I’m being cautious with a 20-percent-by-2020 prediction. We’ll have to check in on this 11 years hence to see who was right! You get the last word.

DeBord: Jim, thanks for trading points of view on this important subject. Changing the power grid is a big part of how we’ll improve the situation. I advocate much more nuclear, for example—mainly because that's where I want us to be in 40 years, when we'll be closer to full-on electric and will need to power both the EVs and the plants that build them. Over the next decade or so, I’m more interested in incremental emissions reductions on a large scale. So I’d like to see us get to maybe 50-60 percent hybrids by 2020, with EVs in the picture, driving (so to speak) innovation and cost-reductions in battery technology. Interestingly, we may never get to 100 percent hybridization, because by then the massive switch to EVs may be ready to happen and feasible from a cost standpoint. Around 2050, we really will have run out of easy-to-access oil, we’ll need what's left or yet to be extracted for agriculture etc., and it will be time to look at fossil-fuel-powered cars as the equivalent of the horse and carriage. But for the next 11 years, we'd be making a mistake to put our money behind EVs when we could put it behind conservation-oriented, oil-powered transportation instead.

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

The turning point? MNN and Slate debate the car's electric future
Battery cars are coming, but when? The car bloggers from MNN and Slate differ on the timetable (but agree we'll all be plugging in eventually).