The 2017 Toyota Prius Prime has set a new benchmark for its efficiency, beating out numerous hybrid and all-electric rivals.

According to the EPA, the plug-in Prius Prime returns 133 MPGe over the combined cycle when running in electric mode. By comparison, the next most efficient model on sale in the United States is the BMW i3, returning 124 MPGe. The Volkswagen e-Golf meanwhile sits at 116 MPGe, Nissan Leaf at 114 MPGe and Tesla Model S 60D at 104 MPGe.

When the Prius Prime was initially unveiled earlier in the year, Toyota said its MPGe range would sit at around 120 miles. Clearly, it was being rather conservative as the car can travel up to 640 miles 1,029 km) on a single tank and 25 miles (40 km) on just electric power.

For those wondering, MPGe is calculated in a very different way to MPG. Whereas MPG looks at the energy source being petrol or diesel, MPGe is calculated around a vehicle that uses electricity as a source of energy. Put simply, it determines how far an electric vehicle could theoretically travel on a single charge if household electricity were priced the same as a single gallon of petrol or diesel.

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