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hill
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Joined: Wed Apr 21, 2010 4:05 pm
Delivery Date: 27 Mar 2011
Leaf Number: 0659
Location: Lake Forest, CA

Re: BESIDES MORE RANGE, what would you like to see in LEAF g

Wed Oct 01, 2014 8:32 pm

Moof wrote:
donald wrote:If you are talking about 'environmental impacts' then give up on discussing having more range.

EVs have a lower lifetime CO2 emission because they 'only' have ~25kWh of battery. Double the emissions for producing a battery twice as large and you wipe out the lifetime CO2 savings compared with an equivalent ICE. If you have to replace a battery twice as large during its lifetime, then you've really destroyed the argument for EVs over ICE, on CO2 grounds.
Nice write-up:
http://environment.ucla.edu/media/files ... CA2012.pdf

Indeed, the battery carbon footprint of a Leaf sized battery is non-trivial. ..... snip.........
I think your assumptions discount the relatively high percentage of owners with PV solar. You CAN run your EV carbon free. Gasoline on the other hand is not only carbon intense while burning - the same is true of its manufacturing / transportation / acquisition via hostile countries etc.
.

donald
Posts: 917
Joined: Mon Jul 29, 2013 12:45 pm
Delivery Date: 29 Jul 2013

Re: BESIDES MORE RANGE, what would you like to see in LEAF g

Wed Oct 01, 2014 11:09 pm

Unfortunately, it looks like he's screwed up the figures.

In figure 10 he appears to be suggesting that the manufacture of a 1500kg car will only generate some 500kg of CO2. The figure is around 6 to 7 tonnes. He only points to references that I cannot access, not what they actually say. I think he's missed a '0' somewhere, or misunderstood what they wrote.

Likewise with the battery, a 24kWh battery also causes the emission of around 5 tonnes of CO2, making about 10 tonnes altogether for an EV.

The battery car should therefore start off with around 4 tonnes of CO2 emissions ahead of an ICE. An 85kWh car would start off around 15 tonnes ahead of a 7 tonnes of manufacturing emissions for the ICE.

If the ICE is generating a tonne of CO2 every 3000 miles and the EV's combined electricity sources generates a tonne's worth every 10,000 miles, it's catching up at the rate of around 2 tonnes per 10k miles. So to catch up the 4 tonnes, it will do so within 20,000 miles. For the 85kWh car, it will take 80,000 miles to catch up on CO2.

If you double your Leaf's battery capacity, you have added 5 tonnes of CO2 to your usage profile. If you drove it for 50k miles, the extra battery size would account for ~30% of all the CO2 emissions your car has caused during manufacture and use to that point.

If there was an option offered to have either 24kWh or 48kWh batteries, you can reduce your CO2 footprint by a third over 50k miles by asking for the 24kWh battery.

colganc
Posts: 1
Joined: Mon Jun 23, 2014 12:04 am
Delivery Date: 21 Jun 2014

Re: BESIDES MORE RANGE, what would you like to see in LEAF g

Sun Oct 05, 2014 2:14 am

Higher efficiency, more miles per kwh. This effectively increases range, decreases required battery size, decreases weight, decreases charge time (for a given range), decreases fuel costs (ever so slightly) or some combination of the above. Imagine a 5.5 mile per kwh efficiency. That could mean a 30% smaller, lighter battery? 30% faster charge time? OR 30% greater range?

I wish I knew how to estimate the efficiency gains if the car was 150lbs lighter and had a .23cd. Would that get the Leaf to 30% more efficient? I wouldn't mind more of a kamm back look or other changes for better aerodynamics. Making the passenger area shorter and going with a more reclined seating position and thus a slightly longer car wouldn't bother me. That would not only help the cd but also decrease the frontal area.

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