Jones Beene wrote: > Just to clear up a couple of points from Jed Rothwell's post: > >> 1. Electric cars consume much less energy per mile so there is not as > much pollution in the first place. > > This is not the correct comparison to make! > > Both future car designs, in the correct comparison, will be electric -- > and will have identical drive trains -- so the energy per mile is > identical; and the comparison then is between having one vehicle: > > a.) operate solely on batteries, such as the Volt
I don't understand the point here. The Volt doesn't "operate solely on batteries": it's a serial hybrid, not a pure EV -- or so says everything I've read about it. Its range is hundreds of miles because it turns on a gasoline powered motor/generator after the first 40 miles. For people whose daily commute is <40miles you could say it "operates solely on batteries", but then *any* PHEV can be said to "operate solely on batteries" if you take that tack -- you just need to carefully specify the range over which it's driven. The only differences I see here between the two cases you describe are that a) GM decided to use ritzy batteries (to get the gas-free range as high as possible, I suppose, or to get better performance as a result of a higher power/weight ratio with lithium versus lead, or maybe just to have someone else to blame if it doesn't work out) b) GM decided to use a gasoline engine rather than a diesel engine for the ICE part of the drive train They could have changed either (a) or (b) without fundamentally changing the car. Changing (a) from lithium to lead would have reduced the development risk but would have reduced the performance (either in gas-free range or in power) and so might have increased the risk of a marketplace flop. Changing (b) from gas to diesel would have increased the efficiency once you go out of "battery range", but I doubt they care about that nearly as much as they care about the ease of finding a place to tank up -- diesel is inconvenient in many locations in the United States, and so would in turn increase the risk of a marketplace failure. Note that if the Volt succeeds, they can easily offer a diesel option later on. They could conceivably offer a lower-price (but reduced EV-only range) AGM or gel lead-acid option later on, as well -- the charging system needs to be replaced and the battery box redesigned, but maybe not much else. And, come to think of it, depending on how "smart" the electronics in the charging system are, maybe they don't even need to change that. The Volt we are hearing about is only their initial entry in the EV market. If it wins, there will be others. And if it loses, it probably didn't matter what it was anyway because that probably means they weren't really in back of it after all (or it means they ran out of money and went bust before it had a chance to take off). > b.) and the other one operate on batteries most of the time, yet > carrying a small diesel engine (motorcycle sized) to recharge the > batteries in an emergency or for the occasional long trip. > > Due to the high cost of lithium batteries, option b.) would cost less, > give greater security, and could be accomplished with low cost SLA > batteries, for far less upfront cost than lithium. > > The downside of option b.) is that the diesel would need to come on for > the last few miles of a long commute (but never for the trips to the > grocery store etc.) > > Plus the big advantage is that option b.) is doable for probably > $20,000 with SLA batteries- versus the lowest possible cost of the PHEV > (which of course, will come down significantly once higher volume is > achieved). Still many customer would rather have the security of NOT > running out of juice on the freeway if the lithiums did not get a full > charge; and another big advatave is being able to take a vacation by car > without renting a vehicle to do it. > > And it is not either/or. There will be a big market for both types. In > the end: option b.) should emerge as the mass market in terms of volume > due to lower cost and flexibility. > >> 2. Pollution abatement at most power plants is much better than for > individual automobiles (except for CO2 of course). > > That would only be true without the catalytic converter, it seems. Or do > you have a reference for that? At any rate, if the backup ICE is seldom > used, the issue is moot. > >> 3. A large fraction of electricity comes from pollution-free sources > such as nuclear power and hydroelectricity. > > On a National average this is what? 35% in the USA ? This is not a large > fraction. > >> In some states, at nighttime when cars will be recharged, nearly all > electricity comes > from baseline nuclear power plants, or wind power in Texas. > > But even in those areas with nuclear power, many consumers would like to > have the backup security of a small diesel. The SLA batteries which are > used, would still charge at night, only for less time as they only need > to give you half the range or less. > >>The diesel will actually get better net efficiency - than going from >>grid-->home-->batteries-->vehicle, because of all the loses at every >>step -- so there is even less net pollution than with the Volt. > >> JR: I doubt it. I have read they are about equal. Certainly not if the > electricity if generated with uranium or wind. Electric power > generation efficiency is improving faster than automobile engine > efficiency, as old coal-fired plants are being phased out and more > wind power comes on line. If the US builds 10 or 20 more nuclear > power plants it will be very difficult for any form of ICE to rival > electric power for low pollution. > > Again - this comparison is being mis-stated. It should not be about the > PHEV compared to the ICE, but instead it is about the optimum design for > a hydrid - which need NOT be the all battery PHEV version. > > A small ICE combined with maybe 6-8 standard SLA batteries makes the > most sense of all IMHO -- even if the ICE (in reserve) is only used by > the driver infrequently.... in fact, the goal would be to design it so > that it used very infrequently, but it is still always there if you need it. > > Jones > > >
