Plug-in hybrid vehicles are certainly the car of the very near future and a core climate solution. And electricity is the only alternative fuel that can lead to energy independence (see here). But I have a long been concerned that General Motors has overdesigned its showcase plug-in hybrid electric vehicle, the Chevy Volt (see here).
Now a major new study by a team of researchers from Carnegie Mellon University, "Impact of battery weight and charging patterns on the economic and environmental benefits of plug-in hybrid vehicles" (see here [PDF]) confirms my basic analysis that plug-ins make sense, but a 40-mile all electric range does not:
We find that when charged frequently, every 20 miles or less, using average U.S. electricity, small-capacity PHEVs are less expensive and release fewer GHGs than hybrid-electric vehicles (HEVs) or conventional vehicles ...
Large-capacity PHEVs sized for 40 or more miles of electric-only travel are not cost effective in any scenario, although they could minimize GHG emissions for some drivers.
Bloomberg quotes Jeremy Michalek, an engineering professor who led the study: "Forty miles might be a sweet spot for making sure a lot of people get to work without using gasoline, but you're doing it at a cost that will never be repaid in fuel savings."
Note that CMU considered a "high gas price" of $6.0 a gallon, which is the equivalent about $200 a barrel, a reasonable high price case for the next decade.
Perhaps the most significant finding for car companies who want to enter the plug-in hybrid business, minimize costs, and frankly crush GM, is something I have thought for a long time -- a very short AER can make sense for a large fraction of drivers:
