Getting the most out of electric vehicle subsidies

Plug-in vehicles may produce fewer greenhouse gas emissions when powered by electricity instead of gasoline, depending on the electricity source. Plug-in hybrid electric vehicles (PHEVs), such as the GM Volt, charge an onboard battery via a wall outlet. They use electricity for propulsion when the battery is charged but also have a gasoline engine for use when the battery is depleted. Battery electric vehicles (BEVs), such as the Nissan Leaf, plug in to charge an onboard battery. They have no gasoline backup, so they require large battery packs to enable longer trips, and they require higher-power charging equipment to refill the battery overnight. Under current federal policy, plug-in vehicles with battery packs at least as large as the Chevy Volt's receive the full $7,500 tax credit, while vehicles with smaller battery packs, such as the Toyota Prius Plug-in Hybrid receive.