Pollution: EV vs ICE

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Bob

Well-known member
Joined
May 24, 2013
Messages
305
Location
New Hampshire
Someone asked me whether my EV was actually saving the environment or hurting it. I didn't know, so I found some documents that give me facts to use in a head-to-head calculation. Please see below and let me know if you see any errors in this approach or if you doubt any of my assumptions.

For EV:
http://www.eia.gov/tools/faqs/faq.cfm?id=74&t=11" onclick="window.open(this.href);return false;
Natural gas (a clean fuel) produces 1.22 Lbs CO2 per kWh produced
Sub-bituminous coal (bad stuff) produces 2.16 Lbs CO2 per kWh produced
Average those to 1.69 Lbs CO2 per kWh
My Nissan Leaf gets approximately 4.5 miles per kWh, better in summer, worse in winter
That means 0.3755 Lbs CO2 per mile or 170 grams of CO2 per mile with a Nissan Leaf

For ICE:
http://www.epa.gov/otaq/climate/documents/420f11041.pdf" onclick="window.open(this.href);return false;
Combusting one gallon of gasoline produces 8,887 grams CO2
Assuming 40 miles per gallon, that is 222.2 grams of CO2 per mile with an Economy Car

I'm ignoring electricity transmission losses (15%?) and also ignoring fuel transportation pollution (no idea), blindly assuming that they wash each other out.

So in this comparison, the EV is slightly better for the environment.

What do you think? Are these assumptions valid? Is the data recent enough? Did I slip a decimal point?

Thank you for your comments.

Bob
 
If you want to make the answer even more accurate, find out what percentage mix your local electric utility uses. Here in Florida, FPL has a ton of nuclear and natural gas, plus I make >1000 Kwh of my own solar electricity per month, so I'm pretty clean. EV critics always want to point at states that generate electricity almost entirely using coal. :roll:

-------------------------------
Transparent aluminum? That's the ticket laddie!
 
just put your area code into fuel economy.gov
http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=34699&id=34614" onclick="window.open(this.href);return false;
 
Natural gas *used to be* a "clean fuel." Now, since you usually don't know if it was an oil well byproduct or was "fracked," you can't assume it isn't actually a "dirty fuel."
 
The real question is, how much electricity is consumed to refine a gallon of gas. The numbers differ, but it is somewhere around 5kwh. So, an ICE car just by pumping 2 gallons consumes 10 kwh of electricity. Make sure to factor those emissions in.
10kwh gets a Leaf quite far while the ICE is just done pumping.
 
The other factor that is often overlooked is the energy used to manufacture the car. Last I saw, producing Li-ion batteries was more energy intensive — from ore to car — than building an ICE and transmission. If it turns out that the LEAF is intended to be disposable, after a few tens of thousands to perhaps a hundred thousand miles, rather than have the battery replaced as it loses usefulness, the numbers would be even worse. Any modern ICE car could be expected to last 200k miles at a bare minimum.

So, fuel used to move the car is the largest energy input, but it isn't the whole story. However, it is worth pointing out that EVs are in the early stage of their evolution and batteries can be expected to improve in useful life and battery manufacture can be expected to become more energy efficient.
 
This topic has been studied and continues to be studied:

http://www.ucsusa.org/assets/docume...ctric-car-global-warming-emissions-report.pdf

Of course, not all studies say the same thing. Older folks will remember that shortly after the initial studies that showed a very high correlation between cigarette smoking and severe health issues the tobacco industry began funding organizations that provided counter-studies. See: http://en.wikipedia.org/wiki/Tobacco_Institute Quite literally many of the people who performed "science" for those groups are now employed providing the same service for the fossil fuel industries, and sadly many people are political motivated to believe the fossil fuel industry studies just as many were motivated to believe the tobacco industry studies.

Consider the infamous 2007 "study" by CNW Marketing Research (first hint: it was a market research firm with no experience in the science fields in question) that purported to show the Hummer was more environmental than the Prius. I can't find it at their web site anymore but you can find literally thousands of positive references to it, including in syndicated newspaper columns (George Will) and the national media. It's too bad I couldn't find it because it is a great exercise in critical thinking - every paragraph contained at least one whopping error or critical omission. If I was to write a sample article with the intent of testing students on their ability to find logical flaws I could not have done better than that "study". Here is but one of the logical responses to it: http://www.pacinst.org/wp-content/uploads/sites/21/2013/02/hummer_vs_prius3.pdf Unfortunately, although the information completely wrong it continues to be widely cited today because it fits a political agenda, the same as with some of the more recent moronic assessments of the environmental impacts of EVs.

The short answer is that EVs do have somewhat more environmental impact than equivalent ICE cars during manufacture, but this is made up many, many times during the operation of the car over its lifetime. The cleaner the source of the electricity, the more the benefit. However, an EV doesn't help the environment as much as not having a car at all.
 
The problem with this number is that it does not consider that many refineries use the waste products to generate their own power... The Chevron refinery in El Segundo, for example, generates about 65% of their power needs from this... When I toured the refinery, they gave me a big pamphlet that broke down power generation and usage, along with many other parameters, in great detail... Thus, while the amount of electricity required may in fact be correct, it is not all being drawn from the grid...

08Wee said:
The real question is, how much electricity is consumed to refine a gallon of gas. The numbers differ, but it is somewhere around 5kwh. So, an ICE car just by pumping 2 gallons consumes 10 kwh of electricity. Make sure to factor those emissions in.
10kwh gets a Leaf quite far while the ICE is just done pumping.
 
If the refineries are really generating or cogenerating the refinement process using their own byproducts to fuel it... they should be bragging... not many are... my guess is that they don't want to prove Musk right about how if we just stopped refining oil we'd have more than enough electricity to power electrics.
 
TomT said:
The problem with this number is that it does not consider that many refineries use the waste products to generate their own power... The Chevron refinery in El Segundo, for example, generates about 65% of their power needs from this... When I toured the refinery, they gave me a big pamphlet that broke down power generation and usage, along with many other parameters, in great detail... Thus, while the amount of electricity required may in fact be correct, it is not all being drawn from the grid...

Since we were discussing emissions where the energy comes from does not matter. How CO2 intensive is electricity generation from refinery byproducts? Sounds quite dirty to me. Dirtier than the grid in fact.
 
Actually, they claim it is quite clean, and cleaner than the grid...

08Wee said:
Since we were discussing emissions where the energy comes from does not matter. How CO2 intensive is electricity generation from refinery byproducts? Sounds quite dirty to me. Dirtier than the grid in fact.
 
Thanks for sharing this Renault study. It's really interesting.

{/humor on} It makes me cringe to see this publicly available on the Renault website but marked Renault Confidential. Does that make me a criminal for reading it? I guess we can leave that to lawyers. :) {/humor off}

Bob
 
I know a lot of people here would probably identify themselves as environmentally conscious at the very least- and would rank the environment as a primary reason for buying the LEAF- but environment was barely on the list for me. It wasn't until after several months of ownership that I began to gain a little more respect for being a proper steward of this space ship we are all stuck on together. But even now, I look at the environmental benefits of driving an electric car from a very skeptical position.

NasGoreList said:
Production phase ice wins, but ev wins over the whole life cycle.

There's a ton of bias surrounding the issue on both sides, but this is my conclusion as well.
 
08Wee said:
The real question is, how much electricity is consumed to refine a gallon of gas. The numbers differ, but it is somewhere around 5kwh. So, an ICE car just by pumping 2 gallons consumes 10 kwh of electricity. Make sure to factor those emissions in.
10kwh gets a Leaf quite far while the ICE is just done pumping.
About 0.2-0.3 kWh of grid electricity is typically used to refine a gallon of gasoline. The 5-7 kWh number that you sometimes hear is the amount of energy that is used. A Watt hour or kWh does not necessarily imply electricity but can be used to measure other forms of energy. Only 3.5-5.0% of the energy used in the refineries is grid electricity. The vast majority is in the form of natural gas and "still gas" which is a leftover byproduct of earlier refining. See Table 4 of this 2008 report:

https://greet.es.anl.gov/files/hl9mw9i7" onclick="window.open(this.href);return false;

An updated but slightly more confusing to read version of this document from 2011 is available here:

https://greet.es.anl.gov/files/petroleum" onclick="window.open(this.href);return false;

The CO2 contribution of this energy is included in the GREET well-to-tank estimate for the CO2 emissions for burning a gallon of gasoline. I believe the latest revised estimate is around 24.5 pounds. Burning gasoline itself emits about 19.4 pounds so that extra 5 or so pounds of CO2 includes that refinery energy overhead.

Unfortunately this misinformation about the grid electricity used by refineries keeps bouncing around the Internets and recently made its way into a grossly misleading episode of Fully Charged.
 
I was searching something about batteries :eek: and found this:
http://www.thefreelibrary.com/Remote+gate+valves%3A+two+decades+of+security+along+TransAlaska...-a019780491" onclick="window.open(this.href);return false;

62 gates each with 110 cels.
I am sure that in Alaska's temperatures or desert temperatures they do not last very long.
 
As others have pointed out, you have to consider the full well-to-wheel impacts to get the answer. The UCS study is a good source, but if you want a more accessible answer, I suggest this Fully Charged video:
[youtube]http://www.youtube.com/watch?v=BQpX-9OyEr4[/youtube]
 
NasGoreList said:
Here detailed study done by Renault on one of their cars that is available in both ev and ice trim:
http://www.renault.com/fr/lists/archivesdocuments/fluence-acv-2011.pdf

Production phase ice wins, but ev wins over the whole life cycle.
Wow, impressive credentials -- the PDF file metadata says the author of that Renault report is "Christ Jesus". Seriously. It doesn't get more authoritative than that.
 
patrick0101 said:
As others have pointed out, you have to consider the full well-to-wheel impacts to get the answer. The UCS study is a good source, but if you want a more accessible answer, I suggest this Fully Charged video:
Yup, that's the grossly misleading Fully Charged episode I just referred to earlier. It's wrong.

I attempted to post a public comment to that YouTube video but even though my comment is marked as "publicly shared" I can't see it when I'm logged out of my YouTube account so I don't think anyone can see it.
 
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