More states are imposing special registration fees on electric vehicles, sparking complaints that the levies undermine efforts to get consumers to embrace alternative-fuel cars.

Twenty-eight states charge from $50 to more than $200 a year for plug-in electric cars, and 14 states have annual fees for plug-in hybrids that also use gasoline, according to the nonpartisan National Conference of State Legislatures. The fees are meant to make up for the fact that electric-vehicle owners don’t buy gas and thus don’t pay gas taxes...