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This seems to be our time for debunking dumb stories about plug-in electric cars.
First, we had to educate a Forbes columnist (and oil-industry consultant) about how the auto industry works.
Now, it's time to offer some gentle guidance to all those journalists who covered last month's release of a study from the Norwegian University of Science and Technology that says, in essence, that plug-in cars are worse emitters of carbon dioxide on a wells-to-wheels basis than gasoline or diesel cars.
We were prompted by a piece on Jalopnik, but it was also covered in many other places.
(We note with amusement that the Popular Mechanics coverage hat-tips a gent who lists Chevron and Mobil as current employers. Uh huh.)
Data is good
In any case, we like data, we tend to like university studies, and we think that, if peer reviews of the Norwegian report hold up over time, it's a valuable contribution to the discussion.
But like all knowledge, there's some important context required to give media audiences a true sense of what it means.
The coverage of the Norwegian report highlights the reductionism often found in science coverage by quick-hit journalists, who take 20 minutes to cover the complex topics found at the intersection of energy policy and the global auto industry.
In almost all the coverage, there are a lot of qualifiers and caveats that reporters neglect in their eagerness to delineate the black and the white.
So here goes.
Norway: Not the U.S.
First, and by far most importantly, the study is more applicable to Europe than to the States.
The study looks at "the present European energy mix," which is vastly different than the various mixes found in the U.S. (Norway has both a very positive attitude toward electric cars and strong government incentives for their adoption.)
Across Europe, the dominant fuel for electric grids is largely coal (with the exception of France, which has a huge amount of nuclear generation).
And in Europe, the baseline cars for comparison are much more efficient to start with: say, 40 mpg on average vs. 25 mpg for the States. Worse, differing test cycles between Europe and the U.S. make head-to-head comparisons quite challenging.
But about those grids: In the U.S., many electric utilities use more natural gas and--in some places--more renewables, including not only wind and solar but also hydro.
Thus the amount of carbon dioxide produced per kilowatt-hour across different U.S. grids varies by more than a factor of two, which makes it dangerous to generalize about the effect of electric cars.
Beware broad conclusions
And that's the biggest problem with the coverage, in our view: What's applicable in a comparison of far more fuel-efficient cars against electrics charged on European grids may be quite different from less efficient U.S. vehicles compared to plug-ins used in states with much cleaner grids.
A single coal plant in a particular grid may not make the plug-in emissions worse, but clearly electric cars are challenged in those states like North Dakota (the very worst) with 90-plus-percent coal.
On the other hand, California, which will buy more plug-ins than the next five states combined, has a grid that's somewhat cleaner than the U.S. average.
So how green your plug-in car is will vary considerably depending on where you plug it in.
Your mileage may vary
Second, as a follow-on to the points above, how green your plug-in actually is depends not only on what grid you use, but what your comparison car is.
Jalopnik hedged somewhat in its piece by saying, "If you live somewhere with oil or coal-fired power plants, then having an electric car is actually far worse for the environment than a comparable gas or diesel car. This includes many areas of the U.S."
That's largely true, for some areas, if your comparison car is a 2012 Toyota Prius hybrid that gets a combined EPA gas mileage rating of 50 mpg.
It's not nearly as true if you're comparing to a more average U.S. vehicle, which gets 20 to 25 mpg.
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It is also worth noting (but complicates the discussion) that emissions does not equal CO2 as implied in the article. There are many other emissions, CO, NOx, particulate, hydrocarbons, etc, that come out of an ICE that do not come out of an EV.
Funny how times change. Used to be these other things were emissions, now people think of CO2
Keep your EV for over 100k miles and you are cleaner. That is the statement from that study and article...
Nuff said there.
Volt has 100K miles battery warranty!
Problem #1.
So,the study made a lot of assumption.
Its basic conclusion is that in the worst case, EV can be worse than the "average" good ICE. But in the best case, EV can be way better than the "BEST" ICE. To judge how beneficial EVs are, you would have to look at all the data and it is more than just MPG. That is a fair statement.
But b/c EVs allow you to "offset" your use phase by using a much cleaner source of energy such as solar, you, the owner can decide how clean the car is where you can NOT do the same in ICE cars.
The energy lost refining one gallon of gas in the US is about 6 kW*h overall (from various sources, not just the grid).
http://gatewayev.org/how-much-electricity-is-used-refine-a-gallon-of-gasoline
So there you have it, just the energy spent refining the gas used by your average non-hybrid is all an EV would need to go the same distance.
68.5 mL/km = 34.5 mi/gal for gas cars
53.5 mL/km = 43.5 mi/gal for diesels and,
.623 MJ/km = .279 Kwh/mile for electrics(LEAF).
It should be noted that the EPA rated the leaf at .320 Kwh/mile. The difference is the Euro cycle because they got the Leaf number from Nissan. (173 Wh/Km)
On a side note, doing some quick and dirty calcs. Running an electric car off of the US grid with NatGas Generation runs equivalent to about a 50mpg car. I think, please correct me if I'm wrong.
(29.3 kWh/gal * 60% Eff * 93% Grid Eff * 3 miles/kWh(Leaf)=49MPG
so, your math would be 33.7x0.6x0.93*3 = 56.41 MPG.
I am NOT sure how you compare natural gas in terms of KWh/gallon.
However, I'd like to point out that buying a used economy car is a far, far better thing for the environment than buying a new electric car...too many times US consumers revert to "new" when used is a very reasonable option.
Extraction of the raw materials that make up the vehicle adds 4%, and only 2% of lifetime carbon is due to manufacturing & assembly.
While hybrids & may be higher in raw materials & assembly, due to added battery pack & electric machinery, the difference in overall lifetime carbon in manufacturing between electric & gasoline cars is negligible.
Study: http://web.mit.edu/sloan-auto-lab/research/beforeh2/files/weiss_otr2020.pdf
Coal plants (1G MW and larger) do not completely shut down during off-peak. In areas with a large percentage coal power end up producing excess energy (NOT ELECTRICITY!) and their capacity factor fall. In areas with a lower coal percentage, capacity factor is above 90 percent meaning plants running at full capacity 24/7.
Its ideal for large coal plants to run 24/7 because of: reliability (cost), pollution, efficiency.
meant 1GW
http://www.americaspower.org/according-to-eia-data
"In 2008, about 48 percent of the U.S. electricity came from coal. In August (2012), that total had slipped to 38 percent, according to the Energy Information Administration."
http://www.businessweek.com/news/2012-11-07/natural-gas-that-backed-romney-may-gain-from-obama-win#p2
Very few electric driven vehicles are registered in states where electricity generated from coal is >40%.
btw: Electric power production in Norway (location of study) is >95% from hydro & wind.
http://www.ssb.no/elektrisitetaar_en/tab-2012-03-29-01-en.html
where as this article speaks of well to wheel comparisons.
just and observation.
If you look at all the emissions related to the production, use and recycling of a car, the batteries are still a problem.
To be honest....
The standard for consumption is based on that but includes all the charging losses at the lowest charging power.
The smart f.e. can be charged at 400V/32A, but the lowest possible charging in Europe is at 230V/8A. That makes for long charging and more losses. Thus, while actual driving consumtion is at 13kW/100km, this goes up to 15,1 in accordance to the standard.
Generally, we use the average national CO2-emission for 1 kWh. There are huge differences between and in the countries.
I have a question.
For those like me that use solar panels on there house to offset the pollution. In most states the sun does not shine when I would be charging my plug-in (at night). Does pushing energy into the grid during the day and pulling it back out at night count 100% as renewable charging and no polution?
Perhaps you should study the possibility that most plug-in car owners will plug in after midnight to take advantage of very low rates, and actually use electricity that would otherwise be generated but not used.
You'll recall that during the brief life of the GM EV car, PS&G offered a $.056 rate per KWh for SO. Cal. EV owners. Nor would it be rocket science to equip plug in owners with reverse meters, allowing them to dump unused juice back into the grid,with time of day credits that actually result in driving at a profit! Solar homes are already doing the equivalent (much to the consternation of some narrow minded utilities). In any event, the claim that plug in electricity will polute more than internal combustion is simply a canard
http://llewblog.squarespace.com/electric-cars/2012/10/11/the-truth-will-out.html
http://energycenter.org/index.php/incentive-programs/self-generation-incentive-program/sgip-documents/doc_download/1140-pev-owner-survey-result
The best estimate I have seen is that it takes ~7.5kWh to make a gallon of gasoline, and it also takes a fair amount of natural gas, as well. So the overhead carbon for both of those have to be added to the total.
Neil
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