GRA
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LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Wed Jul 01, 2015 2:39 pm

Via GCC:
Researchers find Nissan LEAF creates less CO2 than Toyota Prius hybrid in west US and Texas, but more in N. Midwest
http://www.greencarcongress.com/2015/07 ... 1-cmu.html

This joins a long list of studies that show the electricity generation mix is crucial to determining whether or not there's an improvement in GHGs from a PEV. However, this one also concludes that delayed charging overnight is a bad idea in many regions, as much of the baseload is coal-fired and may result in increased GHGs. It also says that the Volt's life cycle GHGs are worse than the Prius in much of the U.S. The study info is here: http://pubs.acs.org/doi/suppl/10.1021/a ... si_001.pdf
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

Zythryn
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Wed Jul 01, 2015 3:53 pm

I've always struggled with what is the best time to charge.
If you are looking only at the power for the car, charging in the Midwest overnight when coal is being burned is worse that daytime when natural gas peak plans are being used.
However, utilities would love to smooth out demand. Using off peak power rather than peak helps delay the need for new power plants.

Of course, if you are using solar, do you charge while the sun s shining, or do you not, and allow your neighbors to use your excess solar power?

The fact that our cars get cleaner as the grid does s one of the things I love about EVs.
Previous owner of Prius, Volt, Leaf & Model S
Current owner of Model 3
http://www.netzeromn.com

GRA
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Wed Jul 01, 2015 4:19 pm

Zythryn wrote:I've always struggled with what is the best time to charge.
If you are looking only at the power for the car, charging in the Midwest overnight when coal is being burned is worse that daytime when natural gas peak plans are being used.
However, utilities would love to smooth out demand. Using off peak power rather than peak helps delay the need for new power plants.

Of course, if you are using solar, do you charge while the sun s shining, or do you not, and allow your neighbors to use your excess solar power?

The fact that our cars get cleaner as the grid does s one of the things I love about EVs.
Some more info: http://www.cmu.edu/epp/policy-briefs/br ... nefits.pdf
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

GetOffYourGas
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Thu Jul 02, 2015 6:30 am

Correct me if I'm wrong, but it seems to me that they are ignoring the fact that currently baseload power plants run overnight, regardless of whether the electricity is used. Whether or not an EV is charged, it is emitting CO2 and other pollutants. Instead of counting that pollution against the EV, they should be looking at incremental pollution due to the EV charging. For the current low take-rates, the incremental pollution is zero. zilch. nada. In fact, studies have shown that we could power something like 70% of light-duty passenger vehicles in the US just on the electricity that is wasted overnight.

Combined with the fact that EVs get cleaner as the grid gets cleaner (and we do need to keep cleaning up our grid), I don't think we'll ever be at a point where a LEAF is dirtier than a Prius.
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV (traded for Bolt)
2015 C-Max Energi (302A package)
2017 Bolt Premier

Zythryn
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Thu Jul 02, 2015 7:11 am

GetOffYourGas wrote:Correct me if I'm wrong, but it seems to me that they are ignoring the fact that currently baseload power plants run overnight, regardless of whether the electricity is used. Whether or not an EV is charged, it is emitting CO2 and other pollutants. Instead of counting that pollution against the EV, they should be looking at incremental pollution due to the EV charging. For the current low take-rates, the incremental pollution is zero. zilch. nada. In fact, studies have shown that we could power something like 70% of light-duty passenger vehicles in the US just on the electricity that is wasted overnight.

Combined with the fact that EVs get cleaner as the grid gets cleaner (and we do need to keep cleaning up our grid), I don't think we'll ever be at a point where a LEAF is dirtier than a Prius.

It again depends upon the focus of the study.
You have to remeber they are going off the standard grid.
they are using 2009-2010 grid data.

They do not include any personal electrical generation such as solar panels or purchasing wind credits.

They really can't though, as those are individual decisions. They could report on percentage of EV owners that take such measures.

One of our groups of utility cooperatives just announced that everyone that gets the EV TOU meter and billing will automatically get free wind credits for it. If more companies started doing that you may be able to fold it in to a study like this.
Previous owner of Prius, Volt, Leaf & Model S
Current owner of Model 3
http://www.netzeromn.com

Alric
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Thu Jul 02, 2015 9:15 am

GetOffYourGas wrote:Correct me if I'm wrong, but it seems to me that they are ignoring the fact that currently baseload power plants run overnight, regardless of whether the electricity is used. Whether or not an EV is charged, it is emitting CO2 and other pollutants. Instead of counting that pollution against the EV, they should be looking at incremental pollution due to the EV charging. For the current low take-rates, the incremental pollution is zero. zilch. nada. In fact, studies have shown that we could power something like 70% of light-duty passenger vehicles in the US just on the electricity that is wasted overnight.

Combined with the fact that EVs get cleaner as the grid gets cleaner (and we do need to keep cleaning up our grid), I don't think we'll ever be at a point where a LEAF is dirtier than a Prius.


Exactly. All these studies just add up the potential GHGs generated per kWh without taking into account how the grid actually works. It's going to be a long time before EVs have a measurable impact on the grid while having real measurable impact on GHGs generated from burning gasoline.

Just consider time of day pricing. My utility offers 20c/4c kwh time of day pricing to encourage people to use more energy at night. They do this because otherwise the utility spends on baseload without use.

NeilBlanchard
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Thu Jul 02, 2015 10:04 am

These "studies" all fail to take the energy overhead of the gasoline into account.

It takes between 7.5kWh and 13kWh per gallon of gasoline to produce; depending on the crude you start with. And guess what? That electricity would power an EV between 25-60 miles.

So, the long tailpipe argument against EV's is moot. Every time someone trots out this cliched idea, we need to take it with a very large grain of salt.

GetOffYourGas
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Thu Jul 02, 2015 10:10 am

NeilBlanchard wrote:These "studies" all fail to take the energy overhead of the gasoline into account.

It takes between 7.5kWh and 13kWh per gallon of gasoline to produce; depending on the crude you start with. And guess what? That electricity would power an EV between 25-60 miles.

So, the long tailpipe argument against EV's is moot. Every time someone trots out this cliched idea, we need to take it with a very large grain of salt.


Excellent point. Although the numbers you quote are much higher than the 6kW I have seen in studies. Still, 6kW can power an EV 20 miles, more than half what a typical ICEV gets from a gallon, effectively cutting its footprint at least in half (while simultaneously increasing that of the ICEV).
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV (traded for Bolt)
2015 C-Max Energi (302A package)
2017 Bolt Premier

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dgpcolorado
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Sat Jul 04, 2015 11:10 am

NeilBlanchard wrote:These "studies" all fail to take the energy overhead of the gasoline into account.

It takes between 7.5kWh and 13kWh per gallon of gasoline to produce; depending on the crude you start with. And guess what? That electricity would power an EV between 25-60 miles.

So, the long tailpipe argument against EV's is moot. Every time someone trots out this cliched idea, we need to take it with a very large grain of salt.
My recollection from when this topic was debated years ago was that it takes a considerable amount of energy to refine gasoline, but that relatively little of it was electricity. Most is natural gas, often used in co-generation, as well as other fuels from the refining process. The result was that the listing of energy use, in refining oil to gasoline, in "kWh" was misleading people into thinking that it was the direct electricity use. It's not that simple.


Edit: Fixed typo by adding missing word.
Last edited by dgpcolorado on Sat Jul 04, 2015 2:24 pm, edited 1 time in total.
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dgpcolorado
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Re: LEAF creates less CO2 than Prius in W. US and Texas, more in N. Midwest

Sat Jul 04, 2015 11:20 am

Zythryn wrote:...Of course, if you are using solar, do you charge while the sun s shining, or do you not, and allow your neighbors to use your excess solar power?...
I tend to charge my car at midday to use my solar generation directly (if it is a sunny day). Although my car draws a bit more power than my panels can produce, a number of neighbors also have solar that they aren't using at midday, so I am using a slight bit of theirs as well (I have the only BEV in my county, so other EVs aren't a factor).

I suppose the decision is helped by the fact that I'm not on a tiered rate and midday is off-peak in this location anyway.
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