Plug-In Hybrid Electric Vehicles
I happen to be looking through an issue of Car and Driver yesterday and noticed their discussion of the EPA’s struggle to measure and report MPG ratings for plug-in hybrids. Apparently, there are people who fail to realize that this is a completely meaningless number. Those who never exceed the battery-only range never need gasoline, and thus experience an infinite number of miles per gallon. Those who never charge their cars experience whatever number is associated with the size and efficiency of the internal combustion engine as it operates their car, given its weight, wind resistance, etc. Of course, most people will experience a number in between – say between 100 and 1000.
But is that really helpful? Can’t we just note that this is metric that doesn’t apply? I had a friend in college who would ask, “How long is a piece of string?” and “Is it shorter to New York, or by car?” It seems to be that the people seriously pursuing MPG ratings for the Chevy Volt and the Fisker Karma are asking questions that have no more meaning than that.
The MPG does apply well to ER-BEV’s – extended range battery electric vehicles like the new coming Volt that will often use gasoline. The MPG helps the Volt with marketing and this may promote “greener” technology adpotion by the average “ignorant” consumer. Since the Volt only has 40 miles pure EV range, it is highly likely that many owners will drive with the range extender engine on. GM reports the Chevy Volt will achieve about 400 miles total – 40 miles EV and 360 miles using the small ICE to electric generator. The 40 miles takes about 8 kWh of energy and at 11.2 cents/kWh it only costs about $0.90 for an electric coal-fired “fill up”. At $2.64 per gallon of the more “evil” gasoline with 7.2 gallon tank, the range extender gives 360 more miles at a cost of $19.02. Effectively 50 mpg but if you add the 40 miles then 56 mpg is fair to argue by GM.
EV’s have very low operational costs. Their issue is really the initial price tag for the vehicle due to Lithium-ion battery costs. The Volt, pure EV’s like the Leaf, up-coming PHEV’s, and even most full hybrids have terrible economic pay back to the consumer. For example the payback time for the Volt is 30 years even when compared to the current Ford Fusion Hybrid (this assumes the Volt will sticker at $40k and tax payers fork out $7500 to the “green” buyer for $32.5k effective sticker price, 10,000 miles/year, 41 mpg on Fusion, $28k price for Fusion).
For pure EV’s in the various segments, the key measures for consumers on the new car window will be: sticker price, cost/mile, range, and charge time. There are of course other value propositions on pure EV’s that a gasoline engine vehicle can never provide and that value we need to see when the “mass” buyer tries them. The first few years of EV’s will easily be purchased at full price by the 6% of American’s who are true green “tree huggers” and who could care less about economics.
There may also be a reasonable chance that the large resource investements into battery research will result in lower cost battery technology with higher power density and lower mass. If there is a break-through then EV’s could grow to mass appeal because of pure economics. Else, at the current technology, they will likely stay very low niche or disappear…again!!
NOTE: Most automotive manufacturers are placing their long term bets in EV’s but not powered by batteries but rather hydrogen via fuel cells….we must closely monitor low cost hydrogen generation technologies using ocean water.