Is the Volt the wrong kind of plug-in?
Too much EV range?Carnegie Mellon University has finished carrying out an interesting study on the "impact of plug-in hybrid electric vehicle (PHEV) battery pack size on fuel consumption, cost and greenhouse gas emissions over a range of charging frequencies (distance traveled between charges)," according to GreenCarCongress.
In many driving scenarios, the study finds that conventional hybrid cars make more sense than any kind of plug-in hybrid. However, if a plug-in can be recharged every 20 miles or less, then a small-battery plug-in hybrid can be more cost-effective than a conventional hybrid. However, large battery plug-in hybrids, such as the Chevy Volt, were never found to be cost-effective.
Higher gas prices, and a number of other issues, significantly affect these results. Still, the study would seem to suggest that a plug-in Prius, for instance, is a more cost-effective approach to plug-in viability than is a vehicle like the Volt.
If true - and this study certainly doesn't establish truth - it would suggest that the government's plug-in tax credits are barking up the wrong tree by focusing on battery size.
Labels: Hybrid Vehicles, plug-in hybrid vehicles
posted by Dahcredyns at
6:55 AM
17 Comments:
Considering recent fleet tests showed the Plug-in Prius only gets 5 miles per gallon more than a regular Prius, I would disagree, that the plug-in Hybrid is the way to go.
The main reason is because the electric portion of the hybrid engine is insufficient to drive the vehicle 100% of the time.
That's why the range extended EV is the preferred route, as the drivetrain is 100% electric.
I suggest reducing the size of the battery in the Volt.
Yes, it will not drive 40 miles on all electric, but it will get great mileage even if the small motor is running to charge the battery.
The smaller battery will cost less, and take less resources to produce.
THIS is the kind of hybrid I want.
I've argued this point before. Even if a plug-in-hybrid only gives you a range on its batteries up to 20 kilometers rather than the 64 kilometer range that the Volt will give you, it will still be attractive to the consumer since it gives you the opportunity to fuel at home and to refuel at a parking lot or a street recharging post.
And I still don't think that there's going to be enough lithium to power all light vehicles in the future. So using alternate batteries with half the range of the Volt and scaling down the Volt's battery to perhaps half its range would be better options.
So I agree with Smurf, GM should look at the option of at least offering a cheaper version of the Volt with perhaps only half the battery range (32 kilometers).
Marcel F. Williams
http://newpapyrusmagazine.blogspot.com/
“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,”
This sentence is a key point from a recent article on this study - People have to realize that the costs of of plug-in hybrids are going to be repaid in more ways than just fuel savings. A key long-term objective is to move US transportation away from an oil-driven economy. This will pay all sorts of dividends down the road. And the biggest savings will be along the lines of future generations of Americans not having to pay the ultimate price for oil - their life or the life of their child on some Middle Eastern battlefield.
Also for those looking for less idealistic cost savings - the government incentive programs for early adopters will help pay some of those costs as well.
Folks really need to step back and look at the bigger picture. And I think they are...
It would be interesting to see how the Volt would function with a smaller battery. Specifically, how would a Volt and plug-in Prius with the same battery perform compared to each other.
EI-
While I agree with you to an extent, I kind of disagree with you. Along the lines of Marcel's battery supply worries, I worry about bang for buck.
For instance, if by 2020 everyone in America could be driving a plug-in Prius or if half of Americans could be driving a Volt, I'd take the Prius path.
I think we have to be wise in how we utilize our resources. Using a little oil or biofuel in a small battery PHEV might be far more efficient and environmentally-friendly than a purely coal-powered plug-in. It might also be far more cost-effective.
A lot of battery, one could argue, is being wasted on the Volt to maintain its sweet spot, for instance.
Likewise, Enerdel has stated that it can make 10 hybrid battery packs for every EV battery pack.
These types of issues need to be included into real world capabilities and dynamics. For instance, how much lithium can be mined in the next decade and how many batteries does that equate to?
To me its simply about efficiency and the efficient use of resources.
One could still argue that large battery EVs will help jumpstart a US battery industry.
On top of that, the flexibility of an EREV drivetrain means that a gen 2 could go in any direction that made sense: smaller battery, smaller EV range, reduced battery life, greater charge-discharge range, etc.
Is there any difference between a small battery Volt and a Prius plugin? Maybe large battery EREVs are a transitional technology.
It would be an interesting approach for GM to lower the cost of Volts by targeting a much shorter usable battery life. Normally planned obsolescence would risk alienating customers, but the bet would be that Volt customers would willingly buy a new Volt every generation or two to enjoy the huge jumps in technology, performance, and cost efficiency.
GM could take a gamble on a cheap, small battery Volt by designing a battery and battery use algorithm that targets a five year usable life and 20 mile range. As part of the cheap Volt model, users could plan on battery/car tradeins at 3-5 years. It would also be good if batteries were somewhat refurbishable, but at least the cells could be repurposed for less demanding uses, like overnight solar energy storage.
With "Moore's Law" for EV cars that we've talked about, EV's will naturally have a shorter half-life than regular cars. Not so much because they will wear down, although battery wear could be significant, but it would certainly mean that just like computers, customers will have a clear value proposition to get a new machine every generation or two.
What alcatholic said... and a a little bit more.
The best part about the Volt is that it is a series hybrid - the gas internal combustion engine is there just to keep the battery charged and therefore electrical power available to drive the electric motor.
There is a bit of engineering here - A series hybrid (e.g. Volt) will be more efficient than a parallel hybrid (e.g. Prius) because of the inherent efficiencies of an electric motor over an ICE (roughly 85% versus 20%). Also, although both have an ICE, the ICE optimized to run as a quasi-constant speed generator will be more efficient than an ICE in a typical car which is constantly throttling up and down.
So as alcatholic was saying - this platform configuration allows the manufacturers to more easily adapt to the market demands and the supply of things like lithium.
For reference - all modern diesel trains are in fact really just big series hybrids.
So Dahch I think we still are on the same page - I'm with you on needing to be flexible on the battery size. In the end all I'm arguing for is to lets make good engineering decisions so that we don't get locked into a way of doing things that makes it difficult to move away (eventually) from fossil fuels (i.e. staying with a parallel hybrid platform configuration like the Prius).
Last note - Are we only talking to ourselves, or does anyone else read this stuff?
The current Prius plug-in CONVERSIONs are just hacks. Their fleet performance should not be judged to generalize the entire plug-in Prius performance. For example, Google's RechargeIT plug-in driving experiment got 93.5 MPG while the fleet plug-in averaged 54.9 MPG.
The reason for the huge difference due to the driver, trip distance, driving condition, etc.. The Iconic Prius (04-09) is not designed to be a plug-in. Some technical explanation: The Iconic Prius has 4 stages of operations to reach it's normal operation temp. During these stages, it uses gasoline to warm up the Cat and ICE coolant temps. If the driver press the accelerator hard, the gas engine will kick in and the warm-up procedure gets started. For the fleet short trips, the plug-in will spend most of the time with the gas engine on.
The Iconic Prius has the thermo bottle system to store hot coolant to assist with the warm-up process but it only works if you turn off the car (for overnight). This system does not benefit frequent engine start/stop of the plug-in application.
2010 Prius was designed to be a plug-in with it's Exhaust Heat Recovery (EHR) system. This system replaces the thermo bottle system of the Iconic Prius. Details for the Prius EHR is not out yet but we can get a glance from the RX450h. http://pressroom.toyota.com/pr/tms/lexus/LEX-14-08.aspx?ncid=12493
Another issue with the Iconic plug-in hack is the battery current limitation. The electric motor is 50kW but the battery can provide only 21kW. The rest comes from the generator turned by the gas engine. In the hacked plug-in, although the battery is more powerful, it only draws 21kW forcing the gas engine to start when the driver ask for more power.
2010 Prius has a more powerful motor with 60kW. Since the official plug-in will be tested in the fleet first, I hope to see the larger battery fully power the 60kW motor.
It doesn't seem like a good idea to make a big hybrid car. The basic purpose of a hybrid car is to consume energy effectively. Regarding this purpose, "Volt" is not a adquiate size of a hybrid car. Of course, the efficiency of the energy might decrease. The plug-in hybrid car is suitable for driving only for short distance, such as for commuting the office in the city.
I don't understand why the Volt has to cost so much. The technology is not new. Electric cars are not new. Using gensets to keep batteries charged is not new. Heck, Ford just saved a ton of R&D money by simply Teaming up with another company, MAGNA, to provide the propulsion system for their upcoming EV. Ford's vehicle will have a range of about 100 miles on batteries alone. Add a genset and you have a Volt.
All of these components are available off the shelf right now.
There is a huge difference between the Volt and the Magna EV that Ford is developing.
In many conditions the Magna EV will achieve far less than 100 miles of range.
The Volt offers essentially unlimited range.
Now that doesn't mean the Volt is better EV than Magna, but making a simple comparison isn't nearly as simple as you make it out to be.
A high gas tax would be the best medicine to hold down gas consumption, and reward fuel-efficient cars.
I am and continue to be a big fan of the gas tax.
1-What is the KWH use per mile on
the Volt vs the Prius...
2-How many KWH's per charging for
each ?
3-How many miles per charging for
each ?
4-How does KWH usage per mile
compare competitively to the new
EV market potential for other
EV's soon to be marketed?
Wanting to compare cost per mile
from the use of grid elecricity.
How many miles per charging ?
Eco Cents-
I don't have all that data right off hand and much if it is rather subjective.
For instance, Volt EV range is 40 using the EPA's city cycle, which is not the stringent. Many battery experts, however, have indicated driving conditions could easily reduce that EV range by 50 percent or more. So, there is a ton of variability.
Moreover, GM's sweet spot, in terms of lithium battery management, means that only 50 percent of the battery is being utilized at any time. The other 50 percent is a redundancy to maintain cell integrity. So, one could argue that the Volt is an inefficient lithium user.
Likewise, EV cost per mile based on today's electricity prices might not be vary accurate either. Most utility analysts claim that electricity prices will rise at least 30 percent within the next decade. If we add cap and trade, or a super smart grid, those costs might go up even more.
Nonetheless, I think they say 3 cents per mile if charged during nonpeak hours.
The GM's Chevrolet Volt has been several years in making. It could that General Motors may just find the answers to our mobility sans pollution. A perfect plug in electric car like Volt will revolutionise the transportation the world over. I wonder what is taking them so long to launch a functional electric car for some time?
Rahul
Indian Car Advisor (Carazoo.com)
I don't think so, many signs point to Buick, a brand that has turned into a surprise hit in China, as being the brand that will get the Volt underpinnings.
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