The big news from the Plugin2010 Conference is GM’s move to match the Nissan LEAF’s lease cost, while cranking up the purchase price to $41,000. Both vehicles will lease for $350 per month, with a $2,000 - $2,500 initial payment. Devoted Volt-heads are expressing disappointment on the sticker purchase price, which could reach about $45,000 with a full set of upgrade options. That price effectively pushes consumers to lease. But what’s the bigger picture?

The key to the low Volt lease is a high residual value. In other words, three years from now, the first Volt leaseholders will have to pay a steeper-than-expected price to keep their car. On one hand, GM is expressing confidence that Volt drivers will absolutely love their cars—and be willing to pay to keeping driving it. But the economics, three years down the road, look rough.

First of all, the Volt will have more competition in 2013 and 2014. The field of electric cars and plug-in hybrids is small now, but in three years, there could be 10 or more compelling plug-in cars to consider. G.M. is promising continual improvements to the Chevy Volt, so the 2014 Volt—with more bells and whistles, as well as potential efficiency and range improvements—will be competing against that same three-year old Volt.

Consider that any new EV at that time is likely to have a $7,500 (or similar) tax credit for the new Volt—putting the three-year-old Volt (which as a used car will not enjoy the incentive), already with a high residual value, even further in the hole. Given the economics, a lot of the earliest of early adopters might be tempted to try out the next great electric car—leaving the 2011 Chevy Volt with the dealership.

At that point, it will be the Chevy dealership’s job to sell the three-year-old first-generation Volt—at a high residual value, without a tax credit, and with more competition from an industry that is making rapid progress with key battery technology. You can imagine that those dealers will want to lower the price. Who knows what effect that will have on future pricing of a new Volt?

Fuzzy Math?

G.M. is counting on the extended range capabilities of the Volt to defy all other economic considerations. The extra range will be appealing to a lot of buyers—but so will pure zero emissions. Which one will be more valuable to consumers?

That's an important question now, but add bigger questions looming down the road. How enthusiastic will Volt owners be in 2014? How much will a gallon of gas cost? How far along will other EV-makers be with their plans? What incentives will be in place in three years?

G.M. had a very tough challenge in coming up with the right price for the Volt. Yet, turning up the purchase price, and dialing the lease cost way down, doesn’t feel right. Of course, it will be great for the first wave of Volt customers wanting to try a plug-in car on for size. But it looks like trouble for G.M. in 36 months. Time will tell.