carbon footprint building a leaf vs IC car

[bytrain]

A highly technical well-to-wheels analysis titled "Contribution of Li-Ion Batteries to the Environmental Impact of Electric
Vehicles" was published in Environmental Science and Technology in 2010 (http://pubs.acs.org/doi/pdf/10.1021/es903729a" onclick="window.open(this.href);return false. Bottom line of that study was that even with high fossil fuel (>50%) electricity mixes, just the operation of an internal combustion engine vehicle causes impacts as high as the TOTAL environmental impacts of electric vehicles (EV). Change the grid mix and the equation only benefits EVs more.

 

[Nubo]

However, in reality, you as well say EV charging at night use 0 kwh energy, because power plants has huge extra at night which can charge millions of EV without increasing output.

The fact that you have huge extra capacity at night means you do not have to build additional power plants or transmission lines to charge EVs. It does NOT mean that you do not need to burn fuel to charge those EVs from plans that burn fossil fuels.

IOW, there's no free lunch here.

Many plants (particularly coal-fired plants) can't simply shut down at night when demand falls. The furnaces must be kept running and the generators producing power, whether it's used or not.

 

[RegGuheert]

Many plants (particularly coal-fired plants) can't simply shut down at night when demand falls. The furnaces must be kept running and the generators producing power, whether it's used or not.

Sure, these are known as base load power plants. But the electricity produced is all used (or is stored using pumped hydro, etc.). The result is that in an area such as where I live that largely has coal-fired plants for base load and natural gas for peaking, adding nighttime loads such as EVs does NOT result in electricity production at the average mix for the area. Rather, it results in electricity production by base-load power plants, i.e. by burning coal.

 

[tbleakne]

The wide-ranging discussions, references, and quotes on this thread suggest to me that the answer to this topic is complicated. I have been focusing my research just on part of this question: what is the total footprint of a particular EV (Leaf or Tesla), including its manufacture.

Another new thread titled "Abt Life-cycle analysis. . ." has a link to a new EPA report that is very long but it looks thorough. This quote from pg 7 summary seems relevant:

Outside of the use stage, primary energy use was driven by aluminum ingot production for the passive cooling system and the extraction of materials to manufacture the cathode. Average primary energy use across the Li-ion battery chemistries totaled 1,780 MJ/kWh of battery capacity, and 2 MJ/km driven.

One kWh = 3.6 MJ (mega Joules), so 1780 MJ = 494 kWhs. I have seen other references to this value. It seems to say that the total energy cost to manufacture the battery is equal to 500 full battery cycles. If the Leaf can go 80-90 miles on a charge, 500 cycles is 40-45 K miles. 500 cycles in a Tesla would be about 3 X more miles.

I have taken the above quote out of a large context. The report has many detailed tables for all the different Li chemistries, and these show that "average" chemistry is misleading, with some parameters varying by factors of 8 between chemistries. I have not yet determined the actual values for the Leaf.

I believe driving an EV can still result in a total footprint less than driving an ICE the same distance, but the further you drive, the better the payoff.

 

[elmobob]

I don't really care if it's more carbon intensive than an ICE over its lifetime. I care that it runs on stuff that doesn't come from countries we are at war with our will in the future. That helps somewhat my conscience.

 

[abasile]

Another new thread titled "Abt Life-cycle analysis. . ." has a link to a new EPA report that is very long but it looks thorough.

Here's a link to that thread: http://www.mynissanleaf.com/viewtopic.php?f=13&t=13464&hilit=life+cycle+analysis" onclick="window.open(this.href);return false;

And the EPA report that it references: http://www.epa.gov/dfe/pubs/projects/lbnp/final-li-ion-battery-lca-report.pdf" onclick="window.open(this.href);return false;

Over time, if researchers focus on reducing the energy intensity of the manufacturing process before commercialization, the overall environmental profile of the technology has the potential to improve dramatically.

By comparison, the overall environmental profile of ICE vehicles is unlikely to improve with time as dirtier sources of oil are tapped. Even in today's worst case scenario, where an EV is overall no better than an ICE in terms of global warming, I'd rather support the technology with the greatest potential for future improvements.

Also, the EPA report emphasizes the importance of battery life in overall environmental impact.

My opinion is that even though an 85 kWh Tesla battery will have a longer "payback" period in terms of miles driven, Tesla's larger, thermally-managed packs seem likely to have far longer service lives than the typical LEAF battery pack. Note that the 85 kWh Tesla battery pack has no mileage limitation on its warranty.

I think Nissan has made a giant mistake in not implementing thermal management. Low-mileage LEAFs in hot locations like Phoenix will of course have the worst relative impacts, probably as bad or worse than conventional ICE cars.

 

[tbleakne]

The July 2013 issue of IEEE Spectrum has an EV hatchet job titled "Unclean at Any Speed" with a car buried in coal on its first page. I am reporting this not because I believe what it says, but because I think it is important for us to know what FUD is out there.

The article quotes from several recent studies, but never gives the exact reference titles or links. One is a 2010 report from the National Academies ". . perhaps the most comprehensive account of electric-car effects to date" The article claims the study says "an electric car is likely worse than a car fueled exclusively by gasoline derived from Canadian tar sands!" A graph supporting this statement shows electricity higher than tar sands gasoline as measured in units of "2030 US cents/mile" whatever that is.

This study's vice chair was Maureen Cropper, an economist at U. of Maryland Energy Research Center. She has authored lots of reports, but I don't see this one.

I have found several related reports on the National Academies web site, but none seem to be an exact match. There is a 2013 report "Overcoming Barriers to Electric-Vehicle Deployment" and a 2010 study of plug-in Hybrid Electric Vehicles.

The tone throughout the IEEE article is hostile to EV deployment and it artfully encourages the casual reader to conclude things are worse than they are. One of the few points that I agree with is that the extra Aluminum in the body of many EVs, such as the Tesla Model-S and 2011-2012 Leafs, does add to the manufacture footprint. Of course ICEs are employing more Aluminum over time as well.

 

[hyperlexis]

The only ICEs that come close to matching or beating EVs' CO2 footprint are hybrids such as the Prius (Prii?). In theory that may even change as the national supply of renewable/lower carbon energy increases.

The one thing I would like to know however, is do the studies account for the basic fact that with EVs, individuals likely drive substantially less than were they operating ICEs or hybrids. Just from a practical standpoint, barring those fortunate to own Teslas, it is impractical if not impossible to drive a pure BEV very far each day, relatively speaking. The amount of energy used is self limiting to distance of travel and recharging times and availability of charging sources. Driving an EV is a much more careful, judicious exercise, forcing people to consciously plan their travel. This in and of itself theoretically also increases the most efficient use of electricity by EV drivers.

So from a practical standpoint, the actual use of energy and CO2 footprint of EV drivers, regardless of the source of electricity used for charging, may be much less than those driving ICEs. For no other reason than EVs must be driven more judiciously and efficiently.

I'd love to see those real-world numbers in a comparative study.

 

[tbleakne]

The only ICEs that come close to matching or beating EVs' CO2 footprint are hybrids such as the Prius (Prii?). In theory that may even change as the national supply of renewable/lower carbon energy increases.

The one thing I would like to know however, is do the studies account for the basic fact that with EVs, individuals likely drive substantially less than were they operating ICEs or hybrids. Just from a practical standpoint, barring those fortunate to own Teslas, it is impractical if not impossible to drive a pure BEV very far each day, relatively speaking. The amount of energy used is self limiting to distance of travel and recharging times and availability of charging sources. Driving an EV is a much more careful, judicious exercise, forcing people to consciously plan their travel. This in and of itself theoretically also increases the most efficient use of electricity by EV drivers.

So from a practical standpoint, the actual use of energy and CO2 footprint of EV drivers, regardless of the source of electricity used for charging, may be much less than those driving ICEs. For no other reason than EVs must be driven more judiciously and efficiently.

I'd love to see those real-world numbers in a comparative study.

You make a good point for someone like myself, who is able and willing to accept the range restrictions of driving a single EV as my only car. However, in my case I am driving more miles per month than I did with my ICE, partly because I feel no guilt.

I believe my case is not typical. Most 2-car households simply use their ICE for any trips that their EV can't handle, so they don't restrict their total miles.

 

[tbleakne]

The following chart appears to be based upon a Canadian study. It may have been posted before, but I only studied it yesterday. It is not quite in the format I would like, but it contains the kind of direct carbon footprint information I have been seeking.

It shows:
1. Carbon footprint of Leaf battery is significant, but NOT an overwhelming share of the car's manufacture footprint.
2. The total Leaf footprint is a strong function of the carbon mix of the electric generation where the car is driven.
Quebec and British Columbia score the best because they are almost 100% hydroelectric.
Alberta scores the worst because it uses coal and tar sand.
3. The chart shows the Leaf in California just barely beating the plugin Prius in BC, presumably because CA uses natural gas for about 50% of its power. However, one can argue that cars charged at night use surplus wind power, and many of us also have solar to pay back our grid usage.

One key caveat from the footnotes: the chart plots tonnes of CO2 for a 320K km (200K mile !) lifespan. We all know that is totally unrealistic for the Leaf on its original battery in CA or most states.

The chart data confirms and quantifies how the more miles you drive the Leaf, the lower your footprint per mile.

 

[Volt3939]

The following chart appears to be based upon a Canadian study. ...
One key caveat from the footnotes: the chart plots tonnes of CO2 for a 320K km (200K mile !) lifespan. We all know that is totally unrealistic for the Leaf on its original battery in CA or most states. ...

I would question the black bars in that chart, which seem to say that all ICE are the same, regardless of size and that a hybrid version takes more CO2 to manufacture, despite the battery being separated from that energy. Some assumptions are baked in there somewhere...

 

[rdhauser]

I did a quick scan of this pdf.

http://www.environment.ucla.edu/media_IOE/files/BatteryElectricVehicleLCA2012-rh-ptd.pdf" onclick="window.open(this.href);return false;

It looks like an honest attempt to me because they published in a classic white paper style with methods and assumptions. Might be an argument with some of them, but I'm comfortable with it.

 

[LeftieBiker]

I didn't read every reply, so this may already have been covered: even if the total emissions were the same (and they aren't), using EVs will dramatically improve the air quality in urban areas, and in other areas where inversions tend to form, trapping exhaust pollution.

 

[tbleakne]

Along with the official announcement this week of the BMW i3 I found a description of the process BMW is using to manufacture the carbon fiber that is key to its relative low weight. BMW has located one of the most energy-intensive processing steps to produce the carbon fiber in WA state. This enables them to reduce the carbon footprint (CO2) associated with the carbon fiber production.

the decision to build the carbon fiber plant in Moses Lake was based primarily on the availability of clean, renewable hydropower and competitive energy costs in the state of Washington.

http://www.sglgroup.com/cms/international/press-lounge/news/2011/09/09012011_p.html?__locale=en

Details of the production process:

http://www.worldcrunch.com/tech-sci...tomobile-environment-sustainability/c4s10613/

I believe this shows BMW is sensitive to the question of CO2 footprint for EV manufacture [hence my posting in this thread], but apparently Audi is not accepting this argument:

AUDI has criticised BMW’s plan to use carbon fibre re-enforced plastic (CFRP) bodies for future city cars, alleging the CO2 emitted during the production of the material far outweighs any fuel economy benefit.

I do question whether reducing weight so drastically improves miles/kWh as much as a similar investment in reduced aerodynamics. Reduced weight reduces rolling resistance, but we know aerodynamic drag dominates rolling resistance for the LEAF. Most likely BMW is more interested in improving acceleration than improving efficiency. Although they have been planning this car for some time, they are surely aware that Tesla is successfully emphasizing performance over efficiency.

 

[tbleakne]

Many plants (particularly coal-fired plants) can't simply shut down at night when demand falls. The furnaces must be kept running and the generators producing power, whether it's used or not.

Sure, these are known as base load power plants. But the electricity produced is all used (or is stored using pumped hydro, etc.). The result is that in an area such as where I live that largely has coal-fired plants for base load and natural gas for peaking, adding nighttime loads such as EVs does NOT result in electricity production at the average mix for the area. Rather, it results in electricity production by base-load power plants, i.e. by burning coal.

You make a good point; thanks for the insight.

I see that you yourself have solar, so you can charge in the day with zero footprint. That is great. You are fortunate that VA does offer Net Metering. The natural gas peaking plants are probably running during daylight hours, so unfortunately your excess solar is replacing natural gas, not coal.

The Tesla site shows that the VA electric mix is 40% nuclear, 37% coal, 17% natural gas.
http://www.teslamotors.com/goelectric#electricity
[scroll over to your state]
Nuclear is also base-load. If you did not have solar, charging from natural gas during the day probably would still be somewhat better than charging from 37/(37+40) = 48% coal at night, but not nearly as bad.

If you did not have solar, I would think the optimum time to charge would be when the peaking plants are running, but not at the peak load of the day, so as not to stress the grid.

In CA we have nice graphics at
http://www.caiso.com/Pages/TodaysOutlook.aspx#Renewables
that display the renewable electric mix over each 24 hr period.

All this shows how the actual, not the average, electric mix is important for both driving and manufacture of EVs.

 

[tbleakne]

The following chart appears to be based upon a Canadian study. ...
One key caveat from the footnotes: the chart plots tonnes of CO2 for a 320K km (200K mile !) lifespan. We all know that is totally unrealistic for the Leaf on its original battery in CA or most states. ...

I would question the black bars in that chart, which seem to say that all ICE are the same, regardless of size and that a hybrid version takes more CO2 to manufacture, despite the battery being separated from that energy. Some assumptions are baked in there somewhere...

For just one example, Toyota Sequoia weighs 5,700 lbs. Steel has plenty of footprint.

 

[rdhauser]

For the original poster. If the PDF I linked to in my previous post is a bit too monkish, this PDF will provide some background material you can arm yourself with:

http://www.greencarreports.com/news/1085997_teslas-musk-promises-deep-dive-into-electric-car-emissions" onclick="window.open(this.href);return false;

Others in this thread might also profit from a review of the links included at Green Car Reports. What I've come away with is that lifecycle costing is fraught with assumptions that have a broad confidence range. Choosing a higher or lower number (which I think is easily justifiable) within the confidence range for many of the assumptions can lead to a different answer.

I hope that Elon Musk does indeed decide to research it as the Green Car Reports article intimates.