Early next year, devotees of the Toyota Prius will have their chance to go a step further into greenness. That’s when the Prius PHV, a plug-in hybrid based on the current Prius architecture, will be introduced.
(To see related content, about the Chevy Volt, go to Drive for Innovation and follow the cross-country journey of EE Life editorial director, Brian Fuller. On his trip, sponsored by Avnet Express, Fuller is driving a Volt across America to interview engineers.)
Design News recently had an opportunity to drive a pre-production version of the Prius plug-in, and the good news is that it’s a sensible alternative-fuel vehicle.
First, it should be noted that, as a plug-in, this Prius is half hybrid and half electric. It differs from other plug-in vehicles in that it employs a relatively small battery. At 5.2kWh, the Prius has a battery capacity that’s about one third that of the Chevy Volt’s 16kWh and about one fifth that of the Nissan Leaf’s 24kWh.
There are pluses and minuses to Toyota’s strategy. First, let’s look at the downside: The Prius has an all-electric range of just 13 miles. If you’re looking for a vehicle that’s more electric and less hybrid, this isn’t it.
The upside, though, is big. Yes, the range is just 13 miles, but the smaller-battery strategy has efficiency written all over it. Smaller means less mass, which translates into greater fuel economy. That’s particularly important when the driver has exceeded the 13-mile range and the depleted battery is basically dead weight.
It also means the recharging time is a fraction of what we’re hearing from competitors. Instead of an eight-hour recharge at 220V (as is the case with the Leaf), the Prius plug-in recharges in about three hours at 110V or 1.5 hours at 220V.
The 110V recharging setup is a huge advantage, not only in terms of availability, but also in terms of cost. During the week we tested the vehicle, we recharged in three hours twice from a 110V outlet. That’s very important in terms of cost, because it means owners don’t need to get their garages rewired at $2,000 a pop.
The biggest advantage of the smaller battery, however, is initial cost. Toyota engineers told us that more range would have translated into about $500 per design mile. Here’s another way to look at it: Numerous estimates have placed lithium-ion battery cost at between $750 and $1,000 per kilowatt-hour. In terms of initial cost, that converts to between $15,000 and $20,000 to get an extra 20kWh.
During our test drive, we got the advertised 13-14 miles of range. When we drove within that all-electric range, our vehicle estimated its own fuel efficiency at 99mpg. It should be noted, however, that even when we drove within the electric range, the vehicle autonomously shifted back and forth between electric and hybrid modes. The main reason was acceleration. When we stepped deep into the accelerator, the car shifted into hybrid mode for about 10 seconds until a constant velocity was reached, and then it switched back. After a low-speed, 4.3-mile circuit, the vehicle’s dashboard display claimed it had been in EV mode 75 percent of the time and in hybrid mode for the remaining 25 percent.
A longer drive was a different matter. As soon as we reached 60mph on a local expressway, the car shifted into hybrid mode and stayed there. The shift was seamless. During a 155-mile ride, the vehicle was in all-electric mode just 4 percent of the time. The fuel efficiency was still impressive, however, coming in at 56.6mpg.
The key to this car’s success on the market, of course, will be its cost. Unfortunately, Toyota hasn’t announced an exact figure. During an interview with Design News, Toyota engineers hinted at a possible figure hovering at around $26,000 or $27,000. But it’s probably safe to say the ultimate entry number will be higher -- possibly landing between $27,000 and $32,000 before tax credits.
The bottom line is that this is a sensible alternative-fuel vehicle for someone who has a short commute to work. Some owners will be able to drive all week in the electric mode simply by recharging every night. Then, when the weekend arrives, they can depend on the car to switch silently to hybrid mode for greater range.