Global sales of plug-in electric vehicles are expected to surge in the second half of the decade, according to a Pike Research study. Plug-in EV sales worldwide will eclipse 1 million in 2017 and 1.7 million by 2020, the study said. In the United States, about 410,000 plug-in EVs will be sold between 2011 and 2015, while cumulative U.S. sales will reach 1 million in 2018. Battery-powered electric vehicles and plug-in hybrids were included in the sales estimates.