Chevrolet Volt, Nissan Leaf will square off later this year

Volt, Leaf electric cars take different approaches to reduce oil consumption, emissions

Compact Volt will cover 40 miles on charge; use on-board generator for longer trips

Subcompact Leaf's bigger battery pack offers 100-mile range; not be capable of longer trips

Nissan has announced Leaf will retail for $25,280, after $7,500 federal tax credit

Volt's sticker price not revealed; expected to cost around $32,500 after same tax credit

Battle could determine course of 21st-century auto industry

Cars represent multibillion-dollar bets by GM, Renault-Nissan

Winner will be early leader in new technology; expected to eventually dominate auto industry

GM, Nissan-Renault try to define what modern electric vehicle is

Takes 8 to 20 hours to recharge Leaf batteries

Volt has 2 power sources, batteries and a generator; cost about $7,200 more than Leaf

"Range is a big deal. The Leaf can't be anybody's sole vehicle." -- Joe Phillippi, principal, AutoTrends Consulting

"The Volt has the standard range people expect from a car. That's an advantage. The Volt could conceivably be a person's primary vehicle. The Leaf is a perfect second car for most people." -- Jim Hall, managing director, 2953 Analytics