The 2017 Toyota Prius Prime is a considerably better than a few electric-car fans had feared.
In fact, with an EPA-rated range of 25 miles (more than projected) and energy efficiency so high—at 133 MPGe—that it matches the BMW i3 with all its whizzy advanced technology, it’s a very viable plug-in hybrid choice.
And it all has to do with one little design choice made by the plug-in Prius design team.
It’s a simple software command, but it turns the Prius Prime from a hybrid into an electric car over its first 20 or 25 miles. That means it’s not the engine-and-electric-combined vehicle that many expected it to be.
And it sets the car apart from every other plug-in hybrid except the Chevrolet Volt, which also operates entirely in electric mode until its battery capacity is depleted.
Sure, their drivers can choose an all-EV mode, but the Prius Prime flips that around, requiring drivers to take an action if they don’t want electric-only operation.
That’s key. And it’s nothing remotely like the driving behavior of the Prime’s predecessor, the now-discontinued 2012-2015 Prius Plug-In Hybrid.
Toyota managed to 75,000 Prius Plug-In Hybrids globally, a large number of the 42,000 U.S. sales on the strength of the California carpool-lane stickers it qualified for.
But just as the fourth-generation conventional Prius hybrid is a far better car to drive than its predecessor, the Prius Prime is a much better plug-in hybrid than the first plug-in Prius.
Better yet, in two different conversations with Toyota executives over the last 12 months, it appears that continuing advances in lithium-ion cell capacity could produce a longer electric range during this car’s six- or seven-year life.
The Prime's lithium-ion battery, located under and behind the rear seat, remains air-cooled, but its 8.8-kilowatt-hour capacity is double that of the first-generation plug-in Prius.
And its EPA-rated range of 25 miles is higher than the 22 miles projected by Toyota when it unveiled the Prius Prime in March.
The weather, in the low 90s, was good for an electric car, but we kept the air conditioning on low throughout our drive.
We completed the 20-mile loop, at speeds ranging from 25 to 60 mph, and still had about 5 miles remaining on the car—though the route contained very little high-speed driving.
That compares to 22 miles for the this year's Ford Fusion Energi, 27 miles for the Hyundai Sonata Plug-In Hybrid, and of course 53 miles for the Chevrolet Volt.
When the battery is depleted and the Prius Prime turns into a slightly heavier version of the conventional hybrid Prius, it is rated at 54 mpg combined (55 mpg city, 53 mpg highway).