Curiously you listed three of the four classifications used by the Department of Energy, and failed to list the fourth:
Extended Range EVs (EREVs)
• EREVs have an onboard battery and an ICE as the second energy source
• Operates in series mode: ICE charges the battery and the battery powers the electric motor(s)
• Normally will operate in all-electric mode until battery is discharged, then ICE turns on to charge the battery.
- No propulsion energy goes directly from the ICE to the vehicle wheels
• Must be plugged into the electric grid to fully recharge and balance its propulsion battery
• Captures energy during regenerative braking
• Examples include the Chevrolet Volt and Renault Kangoo(2003 model)
• Similar advantages and challenges as PHEVs
I suspect, Gary and Andy, that you may (perhaps unconsciously) dismiss this as a separate class because of that final bullet. Let me acknowledge up front that the "challenges" (I would say disadvantages) of PHEVs and EREVs are similar. The Department of Energy lists:
PHEV Disadvantages
– Cost, complexity and added weight of two powertrains
– Higher initial cost
– Drivers adapting to dual-fueling scenario
– Component availability: batteries, powertrains, power electronics
In particular, I am leaning toward a Leaf over a Volt because of the first two disadvantages.
The advantages are also conceptually similar, though in practice EREVs will have a higher AER than PHEVs. However, a PHEV cannot claim to operate in AE mode under all conditions until the battery is depleted, while an EREV can. This is a key point for me, as I often make 10-20 mile freeway trips, and I really do want to avoid using petroleum.
So, why do I care? Just grab my Leaf and be happy, right? Well, a funny thing happened when I took the log I've been keeping and estimated how both a Volt and a Leaf would have done. It turned out I would have used
more gas driving the Leaf. My driving pattern may be atypical, but most days I drive 30 miles or less. Occasionally I drive 150-300 miles in a day. With the Leaf I would have to rent or borrow a car for those longer trips. Even if I used a (stock) Prius on those days, the Volt would get a 30 to 40 mile head start on fuel use, and even if GM is lying about the Volt getting 50 MPG in charge sustaining mode, the Prius would use more gas.
So, perhaps you can forgive me for my reaction a week ago, and for spouting the heresy that a Volt may be closer to an EV than it is to an HEV.