I achieved a new Gen 4 Prius Prime mpge record last Sunday night on my grocery trip. vehicle: blue 2021 Prius Prime Limited @ ~ 24,000 miles outside temperature: 75 ℉ one-way distance: 7.6 mi maximum cruising speed: ~ 25 mph (= 27 mph on the speedometer) A/C use: none fog lights: on audio: on mpge = 33.705 kWh/ge × mi/kWh outbound-trip mpge: 280 mpge = 8.3 mi/kWh round-trip mpge: 276 mpge = 8.2 mi/kWh useable battery capacity: 33.705 kWh/ge × 25 mi / 133 mpge = 6.34 kWh BEV range corresponding to the outbound mpge: 53 miles BEV range corresponding to the round-trip mpge: 52 miles Note that both legs were fairly flat, with minimal change in elevation—so, there is no cheating here. In practice, you can even have a negative mpge if you only drive downhill.
