In a excellent piece this week, Joe Romm reiterated why battery changing stations don’t make sense for electric cars. But he also argued that plug-in electric ranges of more than 20 miles do not make sense because cost gets too high for too little benefit. This seems a reasonable deduction from high (and rising) costs for the Chevy Volt. But this is a case where the efficiency could be cheaper than conservation.
Consuming 0.4 kWh per mile electricity usage, the Volt currently uses a $10,000 16 kWh battery capacity for a 40-mile range. But lots of electric cars get better mileage than that. For example, the Triac only consumes about 0.23 kWh per mile. Admitting this is fairly extreme, there is no reason a car that needs less than half the battery range (and thus does not need to carry as much battery weight) can’t keep its power consumption around 0.27 kWh per mile, which would make battery capacity 11 kWh rather than 16 kWh.
Beyond this, Chevy appears to be paying too much per kWh for battery packs. Reports in the press say the cost of Tesla motors 53-kWh battery pack is around $20,000. Tesla says the current cost of a replacement packs would be about $30,000, and given markups for such things, this suggests the $20,000 figure is not too far off. But even at the retail figure for Tesla, Chevy is paying $625 per kWh vs. $566 per kWh for the Tesla battery-pack cost. Thus the high cost for the Volt battery pack with a 40-mile range should be about $6,100. If the lower cost was right, the total Volt battery-pack cost would be more like $4,100. That means efficiency, and better battery choices, could save Chevy between 80-120 percent by halving the range before the gas tank kicked in.
In short, the high cost of the Volt is not due so much to high battery costs as using batteries inefficiently and then overpaying per unit of capacity. (I would add that using power more efficiently would save additional money by cutting the cost of the electric motor/inverter combination. Requiring less fuel to recharge the car battery when the electricity was exhausted would reduce the size of the fuel tank and the amount of backup fuel the Volt had to drag around.)
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Making buildings more efficient: looking beyond price
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Jon Rynn Posted 3:41 am
06 Feb 2009
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Gar Lipow Posted 3:56 am
06 Feb 2009
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Jon Rynn Posted 4:02 am
06 Feb 2009
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theBike45 Posted 4:28 am
06 Feb 2009
giving opinions about things they know nothing about. First, the Tesla uses first gen obsolete and impractical li ion batteries, while the Volt uses the best out there - from LG and guaranteed to last TWICE as long as those used by Tesla (all 6871 of them!!!). No one knows their exact cost, including you, so shut up already. Cuurent costs don't mean a whole lot anyway, since such large cell batteries (which the silly Tesla does NOT have) have never been mass produced. A123 Systems claims a price drop of over 50%. To demonstrate just how brainless this article is, I point out that the Volt's battery pack does have a capacity of 16 kWhrs, but only 8 of them are available, making your electric mileage calculations 100% incorrect. The Volt achieves exactly 5 miles per kilowatthour. I also note that using a smaller
pack would reduce the power output (power output nat the moment, of course, equals that from the ENTIRE pack).
I also note that electric mileage obtained is all about commuting distances and that a Volt with half the driving range would avoid far less than half the gasoline consumption. The math is so simple even our simpleminded President could figure that out.
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biodiversivist Posted 4:31 am
06 Feb 2009
I like this design very much and would be happy with a 40 mile range package:
http://gristmill.grist.org/story/2008/7/29/11131/6360/#6
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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Jon Rynn Posted 5:25 am
06 Feb 2009
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mphtower Posted 5:40 am
06 Feb 2009
The Volt, on the other hand, is a mass-produced vehicle designed to satisfy the needs of the consumer market.
The Tesla and other such performance vehicles come from a cost-is-no-object concept, whereas cost is very important to the Volt. Although Chevy will undoubtedly lose money during the initial run, as Toyota did with the Prius, they intend to make this profitable by the first redesign.
With this in mind, there are sacrifices that need to be made to keep the car at a reasonable price. I doubt anyone reading this site could afford to spend the amount of money to buy a Volt that would offer the same range, charging time, level of comfort, handling, yet also uses the most efficient and advanced materials on the market.
One could just as easily ask why the Volt is made out of commonly available materials instead of carbon fiber, kevlar, and aluminum honeycomb to reduce the weight. The answer, of course, is that it doesn't make sense for the market.
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Gar Lipow Posted 6:06 am
06 Feb 2009
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mphtower Posted 6:54 am
06 Feb 2009
I guess I should explain more, since I left some things out to prevent my response from being too long.
The first thing to be mentioned is that neither of us know exactly why GM has selected the vendor and battery they did--this is all supposition.
But, my understanding/guess as to the differences in cost between the Tesla and Volt come down to these points:
The Tesla is a technology showcase for an upstart firm. As a result, their vendors are willing to operate at a lower margin to "get in the door", so to speak.
It's possible that GM's vendor is reaming them a bit, but it's also possible that the batteries cost more per kWh because of the point you made about using half the capacity (or some variation) of their battery pack. Yes, they could use fewer higher quality batteries instead, but will that have the lifecycle of more batteries operating less efficiently? One need only look at the Toyota vs. Honda mindsets of engine design and lifespan of their respective engines to see that the Toyota approach of understressing reaps further rewards down the road.
Back to profit margins: Vendors for the Volt realize that this is a mass-produced vehicle and cannot afford to operate at a "get in the door" margin. I would guess that they are operating at a lower margin than usual to help make the Volt a success, but they can't afford to drop their price too far with the expected sales.
Tesla doesn't need their car to operate flawlessly for 100,000 miles for it to be a success, whereas GM absolutely does. To this point, GM requires a higher standard of QC than Tesla does.
Again, I can't say for certain (and no one except the bean-counters at these companies would be able to), but I think that Tesla and their vendors are making a lot of concessions to be able to demonstrate the viability of their product. GM, for many reasons, can't afford to make quite as many concessions.
I hope that explains my thoughts on this a bit better.
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Nickz Posted 7:19 am
06 Feb 2009
Really, no one knows how much the batteries cost, including the CS Monitor. The $10K figure is purely speculation.
The batteries won't be produced in large volumes for several years. They'll use less expensive materials than 1st Gen batteries; the larger format is much less expensive; and they'll have very, very large production volumes relative to most 1st-gen li-ion.
GM is pricing the Volt high purely to capture the early-adopter premium and the federal rebate - their official justification is that they're pricing in 100% replacement of the battery under warranty, which really isn't credible. We can expect the Volt to cost less than $30K with large volume production.
Yes, they could be less conservative than their 50% depth of discharge, but there aren't any batteries on the market that are more durable as measured in charge cycles. Tesla's batteries aren't expected to last more than 400 cycles, and the Volt will do 5-10x as many.
In theory, the Volt could have a smaller battery to more perfectly optimize costs, but then it wouldn't feel like a big step forward. It wouldn't feel like a real EV, with generator backup - instead, it would feel like an incremental hybrid. Both GM (for PR) and buyers want a large, step forward, I think.
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Nickz Posted 8:06 am
06 Feb 2009
That doesn't suggest that the reporter has any firm source for this info.
Elsewhere, the article says: "Still others say that the cost of new battery power for PHEVs may drop faster and already be lower than what has been widely reported at perhaps $500 per kilowatt-hour or even less, says Suba Arunkumar, analyst for market researcher Frost & Sullivan.
"I do expect the price will come down to perhaps as low as $200 per kilowatt-hour when mass production begins in 2010 and 2011," she says."
Tesla's cost is $400/KWH - it's very likely that GM will pay $200-$300 in volume.
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Nickz Posted 8:09 am
06 Feb 2009
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Duggles Posted 4:30 pm
06 Feb 2009
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Gar Lipow Posted 1:50 pm
09 Feb 2009
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tsport100 Posted 5:10 am
08 May 2009
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tsport100 Posted 5:15 am
08 May 2009
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drewtiss Posted 11:52 pm
17 Jul 2009
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