Efficiency of the plug-in electric car is unmatched anywhere else in today's automotive landscape.
The top ten most fuel efficient light vehicles in the US, as measured by the EPA, consists only of plug-ins - nine all-electric vehicles and one with range extender/plug-in hybrid*
Plug-in cars are compared using a miles per gallon equivalent (MPGe) rating, which assumes 33.7 kWh of electricity is equal to one gallon of gasoline.
In the final 2016 results, the best of the best is the Hyundai IONIQ Electric, which opens the table with 136 MPGe, nearly 10% higher than second BMW i3 (old 60 Ah version)! Well, kinda*...as the EPA apparently has not gotten the specs for all the 2017s sorted out, including the 2017 Toyota Prius Prime - which at 133 MPGe is nearly as impressive as the Hyundai, as well as he likes of the new Ford Focus Electric (107 MPGe), of the Model S (104 MPGe), etc
The point is, to be even in contention for one of the 'top 1o' (or top 25) most fuel efficient vehicles in the US...you have to be able to plug in these days.
As of today only nine models exceed 100 MPGe combined fuel economy level.
Top Ten Most Fuel Efficient Light Vehicles, MY 2017
Vehicle Photo Vehicle Combined Fuel
Hyundai Ioniq Electric Automatic (A1) EV 136 150/122 BMW i3 BEV (60 Amp-hour battery) Automatic (A1) EV 124 137/111 Chevrolet Bolt Automatic (A1) EV 119 128/110 BMW i3 BEV (94 Amp-hour battery) Automatic (A1) EV 118 129/106 Fiat 500e Automatic (A1) EV 112 121/103 Mitsubishi i-MiEV Automatic (A1) EV 112 121/102 Nissan Leaf Automatic (A1) EV 112 124/101 Kia Soul Electric Automatic (A1) EV 105 120/92 BMW i3 REX (94 Amp-hour battery) 0.6 L, 2 cyl, Automatic (A1) PHEV 88 95/81 Mercedes-Benz B250e Automatic (A1) EV 84 85/82 Note: A1 = automatic transmission with one speed. Source: U.S. Department of Energy, Fuel Economy data, Fueleconomy.gov Top Ten, accessed December 1, 2016.