Hybrid-electric vehicles can be modified to recharge from home electrical outlet. Commuting on battery power only voids the warranty. Several OEMs are working on factory-built plug-in hybrids. Incremental costs estimated at $10K. A lithium-ion battery breakthrough is needed to make plug-ins affordable enough to become widespread. Electric power plants must clean-up emissions further to ensure the plug-in environmental benefits are actual and not transferred to a different source.