Whither the Volt

Via Jim Kingsdale:

Since PHEV's [plugin hybrid electric vehicles] can have so much impact on both the energy investment outlook and national security, I follow with some interest the news about their likely availability.  Recently a picture is starting to emerge.  It is not positive for American car companies, of which G.M.'s Volt is the poster child.  This is not totally surprising given G.M.'s proven history of incompetence.

We know that the Volt's battery is so expensive that G.M. proposes to sell the car for $40,000 - a price that would eliminate most buyers.  And even with such a high price G.M. promises they would lose money on every vehicle.  So, as I've previously written, the Volt may well be more of a political strategy for G.M. than a likely transportation solution.   Now a new study by Carnegie Mellon University says the design of the Volt's propulsion system is inherently sub-optimal and uneconomical - "not cost effective in any scenario" in the words of the study.

The reason is quite obvious once you think about it.  G.M. designed the Volt battery to go 40 miles on a charge because, they "reasoned", some 90% of all drivers go no more than 40 miles in a day.  What Carnegie Mellon points out is that the average driver goes less than 20 miles in a day.  Therefore the Volt's battery is twice as large as necessary for some 50% of drivers .  Since battery weight and cost are the prime determinants of a PHEV's cost-effectiveness, the Volt battery is about twice as large as is economically practical for most drivers.

Here's how the report put it: "The Carnegie Mellon study, conducted by engineers from three different departments, constructed computer simulation models to determine the impact of additional batteries on fuel consumption and cost and greenhouse gas emissions over a range of charging frequencies.  It found that small-capacity plug-ins that get less than 20 miles per charge are more efficient than conventional hybrids. And it said that large capacity hybrids like the Volt that go 40 miles or further on a charge are never cost-effective, because the batteries cost and weigh too much.  A car with the Volt's range, according to the study, would also be extremely uneconomical traveling fewer miles as it hauls around battery capacity it doesn't need."

So much for the Volt.  Ciao - and lets hope the U.S. govt. is smart enough not to fall for the Volt's fools-gold as an excuse to keep G.M., a chronically mismanaged company, from enjoying the cleansing benefits of bankruptcy.  Among which benefits might be new management.


  1. Charlie B.:

    Methinks 20 miles per charge is out of touch with real world experiance. Golf cart manufactures routinely sell 60 mile per charge carts in golf cart communities in Florida.

    The key factor is the recharge time. If it is too long, kiss off that second 20 mile trip today. The 60 mile golf carts shop in the morning, golf in the afternoon, go to dinner in the evening, and recharge overnight.

  2. Philip:

    I think you misunderstand how the Volt is designed. It has a small ICE which will run to charge the batteries after the 40 mile mark is reached. Other PHEVs would presumably be the same, so it is disingenuous to say that you could not drive 20 miles in a day unless you are talking about electric only vehicles, which the Volt is not.

  3. Link:

    It's hard to compete with gasoline and diesel fuel, even if they were to cost $10 gallon. They're "too good."

    The greater upfront cost of a hybrid can only be justified if gas is expensive and you drive a lot. It's easy to figure this out ... you just calculate the payback period and get a rate of return. The numbers don't work at $4 per gallon. They certainly don't work at $2.00. My simplisitic explanation for why a hybrid will always cost more is because you're paying for two engines, not one.

    Plug-ins are glorified golf carts ... and you need to get the electricity from somewhere. A way to visualize the problem is to show the gas tank from a current car next to the batteries you'd need to replace it to drive the same distance. I'm sure the comparison today wouldn't be flattering, even for a smallish ten gallon tank.

    If we want Americans to be more economical in their use of gas -- either because of environmental concerns or because we want to reduce our dependence on foreign sources -- we should slap a hefty tax on gas the way European countries do. Folks like Obama won't do that because they know it'd be political suicide. So instead they're trying to get in the auto design business .... what a joke.

  4. Allen:

    Thanks for the update. I don't buy into global warming, at least that the man-caused portion if it exists is making an impact that is worth getting our undies in a bunch. But I am interested in finding ways of reducing tail pipe emissions, among others, since they're a large portion of localized pollution like ground level ozone. That's a problem in places like Denver where I live. It's too bad this sort of thing still looks to be decades away from being reasonable to use and help alleviate this sort thing.

  5. joshv:

    "Methinks 20 miles per charge is out of touch with real world experiance. Golf cart manufactures routinely sell 60 mile per charge carts in golf cart communities in Florida."

    I'd love a 20 mile per charge plug-in hybrid if it makes it cheaper. I'd say easily 95% of my trips are in the city and less than 15 miles total. I go out, hit a few stores, and come home for the day. Everything is so dense in the city that I don't really have to deal with suburban driving distances. Hell most people in the city use their cars only to drive 10 blocks to the grocery store a few times a week.

  6. Roy Lofquist:

    Lithium ion batteries deteriorate 20% per year. Thus, the cost of a vehicle that lasts 15 years must include the cost of 3 batteries.

    Perhaps far more significant, however, is that there would be no market for a 5 year old vehicle because it would be $6,000 more expensive than a gasoline powered vehicle - a considerable portion of the market value of a 5 year old car.

  7. Bob Smith:

    But I am interested in finding ways of reducing tail pipe emissions, among others, since they’re a large portion of localized pollution like ground level ozone.

    Further reductions in tailpipe emissions are pointless, modern gas-engine emissions controls are so good that a warm engine emits essentially zero pollution (and darn close to zero when cold). If you have an ozone problem, it's not from new cars, it's from old cars. Reducing the emissions standards on new cars, which are literally 99.99% clean, when you have older cars on the road that are the pollution equivalent of 1,000 new cars, is economic and environmental insanity.

  8. frankania:

    As an engineer, I wonder about the rush toward "electric" cars. They are inherently LESS efficient than gasoline, because the electricity used to propel them has to be generated by a (usually) fuel-burning generator and there are efficiency losses.

    In areas where HYDRO-ELECTRIC power or solar or wind is used to charge the electric cars, then they would be better than gasoline-power.

  9. rxc:

    As a CMU alumnus, I, am embarrassed to see these sort of stories. Taking average values to use in engineering design is poor practice, because it gets you into trouble when the facts on the ground deviate from "average", which happens 50% of the time. Electric cars that only go 20 miles require the owner to have a second vehicle that has the sort of range to do the long trips - I use the DC to NYC trip as a standard. The vehicle has to be able to haul 4 adults that sort of distance (about 250 miles) in January (providing heat all the way), and in August (air conditioning) without refueling. That is the standard that people have come to expect, and no electric vehicle can meet it. I think I have read that flywheels might have the energy storage capability, but they have the downside of coming apart "energetically" when they fail, which is not a good thing.

    Much better to shift to a nuclear economy, with high-temperature reactors converting coal to liquid fuels, instead of burning it as a boiler fuel.

  10. K:

    It is obvious that GM made a huge bet on how good batteries would be by 2011. And about what they would cost for the Volt.

    The outcome still isn't clear but IMO the batteries will cost too much by 2011. And therefore the Volt will not be profitable.

    But concern about exact battery range is a diversion. Once everything else is ready it won't be much of a trick to offer Volt versions with electrical ranges of 20, 40, or 60 miles at various price points. The real trick will be getting a good quality Volt to dealers while anyone is still interested.

    The economic collapse has brought GM to bankruptcy - unless they are bailed out. But either way some portions will continue to operate. I think Corvette is profitable, and Cadillac, and some overseas operations. Whether their bet on Volt will continue in such an adverse climate is not known.

  11. heretic:

    I thought that the "energy balance" of plugin electric was proven to be horrible years ago. So much energy is lost in the transmission and conversion of electricity, that it cannot compete with point of use hydocarbon fuels.

    If you were to pile on the incremental infrastructure costs of generating and transmitting greater quantities of electricity, and the higher vehicle production costs, and the greater vehicle weight, it's a lose-lose-lose-lose-lose proposition.

    I would also bet that in most locations the cost of powering such a vehicle would be higher than for petroleum.

    For the small number of people who benefit from low prices due to proximity to hydroelectric or geothermal sources, it might make sense.

  12. davidcobb:

    A PHEV is first and foremost an electro-motive drive (like a train). The ICE can be smaller and more efficient because it runs at a constant speed and load. the bateries would be used balance the load (charge under light loads and discharge under heavy loads). They also can be used for short trips were the ICE does not have enough time to warm up to the point were it can operate cleanly and efficiently. This makes the Volt still more of a POS by missing the point.

  13. A Stoner:

    Quoting Allen above... "But I am interested in finding ways of reducing tail pipe emissions, among others, since they’re a large portion of localized pollution like ground level ozone. That’s a problem in places like Denver where I live. It’s too bad this sort of thing still looks to be decades away from being reasonable to use and help alleviate this sort thing."

    If I am not mistaken, electric motors create ozone?