No plug-in hybrid can match the efficiency of the Toyota Prius Prime.

Here we have an all-new comparison of plug-in hybrid models, currently available in the U.S. (see the full list), with a focus on energy efficiency.

For the comparison, we will use the combined EPA result in all-electric mode (MPGe and calculated Wh/mile equivalent), as well as the combined result in hybrid mode (MPG), used once the battery is depleted.

Some of the PHEVs are quite efficient, while many of the high-performance or big luxury models are clearly electron guzzlers.

Plug-In Hybrid Car Efficiency Compared For U.S. – July, 2020

The top models in our rank are:

  • Toyota Prius Prime: 253 Wh/mile (157 Wh/km)
    EV mode: 133 MPGe
    HEV mode: 54 MPG
    EV range: 25 miles (40 km)
  • Hyundai IONIQ Plug-In: 283 Wh/mile (176  Wh/km)
    EV mode: 119 MPGe
    HEV mode: 52 MPG
    EV range: 29 miles (47 km)
  • Honda Clarity PHEV: 306 Wh/mile (190 Wh/km)
    EV mode: 110 MPGe
    HEV mode: 42 MPG
    EV range: 47 miles (76 km)

The least efficient models need about 600-850 Wh/mile (373-528 Wh/km) in EV mode, which makes them really difficult to electrify and achieve a high all-electric range. They simply need a relatively big battery.

The energy efficiency drops significantly, by 2-3 times, once the battery is depleted. This makes it very important to select aPHEV model which fulfills all the needs and stays in EV mode on a daily basis (aside from long-distance travel and emergency backup).

One might wonder, how the good-old Chevrolet Volt compares to the current top three, so let's see:

  • Chevrolet Volt: 318 Wh/mile (198 Wh/km)
    EV mode: 106 MPGe
    HEV mode: 42 MPG
    EV range: 53 miles (85 km)

The Volt was also quite efficient, with top range, in general pretty close to Honda, although significantly smaller.