Toyota’s Prius Prime saved me gas money but probably not the environment

I’ve always wondered what it would be like to own a plug-in hybrid, and recently, fate handed me that opportunity. On a recent trip to Vancouver, I rented a 2024 Toyota Prius Prime for nearly two months — the ideal scenario to try out North America’s most popular PHEV.

My experience with the Prius Prime

Previously, the words “Prius” and “sexy” were rarely used in the same sentence. However, I think the wedge-shaped Prius Prime introduced for 2023 is much sexier than its frumpy predecessors. The sleek shape also pierces the wind better to improve efficiency. It’s lower to the ground than before, though, which can make entry tough for taller or older people.

I was comfortable in the Prius Prime once seated, even though the materials and options aren’t quite as luxurious as other PHEVs sold in the US. On two 10-hour highway drives up to northern Canada I never felt sore (or cold) in the well-bolstered, heated seats. However, visibility wasn’t the greatest due to the low seating position and thick front pillars that occasionally blocked my view of traffic.

With its wraparound dash and 8-inch touchscreen, the interior is reasonably high-tech but not to the standard of some EVs I’ve tried recently. It came with wireless CarPlay and Android Auto support that gave me seamless streaming entertainment on long highway stretches. The driver safety features (lanekeeping, adaptive cruise, automatic braking and more) also boosted my confidence in Vancouver’s gnarly traffic. The Prius Prime doesn’t offer true one-pedal implementation, but it has a mode that’s close to that.

With a two-liter 150 HP gas motor and 161 HP electric motor (net 220 HP combined), the 2024 (fifth generation) Prius Prime has a whopping 100 more horsepower than the previous model. The electric drivetrain is supplied by a 13.6kWh battery (10.9kWH usable) that takes four hours to charge at 240 volts, or double that with 120-volt household electricity. That means you can juice it fully overnight, but it doesn’t have DC fast-charging for speedy power-ups on longer trips. The EPA electric range is 44 miles, 19 more than the fourth-gen Prius.

It accelerated surprisingly well (from 0 to 60mph in 6.7 seconds) and was agile, but had a fair amount of body roll since it’s not designed for the race track. Still, considering the Prius’s reputation as a staid hippie econobox, the new model was downright sporty. I enjoyed driving in the all-electric mode much more than the hybrid mode, though — it was quieter and smoother, with lower noise levels and vibration.

So, how far was I able to drive on that electric motor alone? On the highway at about 65 MPH, I eked out 30 miles and just over 40 miles in the city. On one trip, I drove from the city center to a suburb 30 miles away and made it there and partially back on a full charge. On another voyage, I was able to drive back and forth between the east- and west-most points of Vancouver (13 miles) — a typical commute for many city-dwellers — with about a quarter charge to spare.

With consistent charging, my fuel consumption over a two week period (averaging 25 miles per day) was about a quarter of a tank or around $7.50. In terms of electricity, I used nearly 70.5kWh during that time at $.085/kWh, for a total of $6. All told, I spent $13.50 for gas and electricity over 350 miles of mixed driving, so the Prius Prime was clearly cheap to operate.

For longer trips, it’s still as inexpensive as it gets for a gasoline-powered vehicle, thanks to the efficient ICE motor and hybrid system that’s among the best in the industry. With a full battery charge and tank, I set out on a 547-mile drive and travelled 470 miles before stopping for gas, with a quarter tank to spare. That fill-up cost around $25.

The true savings and the problem with plug-in hybrids

The timing for my test of this car was ideal. In October, I spotted a European study concluding that PHEVs aren’t as economical as expected over a large sample size. Engadget’s article about that stirred up some passion among owners and potential buyers, so I wanted to compare my experience with points in the study.

First, let’s see if a PHEV is worth the extra money compared to a regular hybrid. My calculations are for the average US buyer and don’t take state or federal clean air rebates into account.

When I chose to rent a “compact” car, Avis assigned me a mid-range Prius Prime XSE — a model that lists at $37,320 but typically sells for $34,590, according to Edmunds. That suited me well as it only lacked a few features of the high-end XSE Premium, notably the larger 13.2-inch infotainment display and solar roof option. A fully equipped 2026 XSE Premium model with those features costs $41,665.

Since Toyota also makes a regular hybrid Prius, that vehicle offers an ideal comparison. The equivalent Prius XTE model has a list price of $31,995 in a similar configuration, making it $5,325 cheaper than the Prius Prime XSE.

The average US driver covers 13,662 miles per year and gasoline currently has a median $3 per gallon price. Over that distance, a non-PHEV Prius driver could expect to burn 273 gallons at 50 MPG (EPA combined) in a year, spending $819 on fuel.

A Prius Prime driver, on the other hand, would use 70 to 85 percent less fuel by current EPA or WLPT estimates. If we generously take the high end of those numbers at 85 percent, that cuts fuel costs to $160. That would require using about 2,500 kWh of electricity, though, so at an average US price of $0.18/kWh, that amounts to $450, for a total of $610 (gas plus electricity). That means you’d save just $209 in a year, or $2,090.00 over 10 years — not enough to justify the extra price. (Fuel and electricity prices, usage and other factors vary by region and can have a big impact on those figures.)

It could be even worse than that, according to a European automotive thinktank called Transport & Environment (T&E). After gathering real-world OBFCM data from 800,000 vehicles, they determined that PHEVs only run in all-electric mode 27 percent of the time, rather than 84 percent as estimated by Europe’s WLPT standard. As a result, plug-in hybrids in Europe emit five times more emissions and cost users €500 ($586) more per year than previously thought. Those figures are likely similar in the US.

How could regulators be so wrong about this key data? The first, obvious reason is that they underestimated how often people charge their vehicles. With their relatively short range, plug-in hybrids often need a full charge to get through the day in electric-only mode — but many people aren’t doing that.

Why? One reason may be a lack of easy charger access away from home. I found them to be difficult to find and use, often requiring a sign-up or app rather than just letting me tap a credit card (I’m looking at you, ChargePoint, Flo and Switch Energy). It can also be more expensive than just buying gasoline, since many companies charge triple or more the market rate for electricity. Another factor is that drivers of company or fleet PHEVs charge their vehicles less often than private owners.

There’s one additional and especially pernicious reason: The ICE engine often kicks in when PHEVs are supposedly running in all-electric mode, particularly with heavier sedans or SUVs. That’s because the electric motors alone aren’t powerful enough for maneuvers like passing.

Larger batteries can boost all-electric usage, but only to a point. Beyond 45 miles of range, emissions actually increase. The reason is simple: “Long-range PHEVs are the heaviest in the dataset, averaging 28 percent more mass and 33 percent more engine power than the group just below,” T&E wrote.

Overall, I enjoyed my time with the Prius Prime and found it to be fun, practical and cheap to drive. It’s the most economical PHEV because it has excellent electric range and enough power that the ICE engine rarely needs to kick in. At the same time, it offers the highest EPA mileage rating of any non-EV sold in North America. If I were in the market for a new vehicle, the Prius Prime would be high on my list.

However, I also learned that PHEVs aren’t reducing emissions or saving buyers as much as regulators and manufacturers have promised. Governments are to blame for much of that, as they overestimated all-electric use in PHEVs and failed to support the charging infrastructure needed to make them practical.

Responsibility also falls to automakers and buyers. Consumers want SUVs, but manufacturers aren’t making the electric motors in PHEVs powerful enough to run all the time in EV mode or offering fast DC charging. At the same time, drivers are failing to charge their vehicles consistently. Until those issues are solved, in my experience plug-in hybrids are a poor substitute for EVs in terms of emissions and a less economical choice than regular hybrids.