Though not as comprehensive as I would have liked, I found this chart to be of value.
Even With Coal Power, Plug-Ins Beat Your Average Car | EcoGeek
Even With Coal Power, Plug-Ins Beat Your Average Car | EcoGeek
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
That seems pretty normal as solar in those data has 0 CO2 emissions and coal with CO2 storing has a little bit, as in 16. The big yellow part of the graph is the gasoline part of the hybrid drive.
Cobos
Cobos
I always wonder about these things - are they really counting just the end product of gasoline, or including the entire oil production chain, drilling, pumping, shipping, refining, etc. Those steps can be quite energy intensive.
The figure I've seen before was that gasoline production is 85% efficient. That comes from the oil&gas industry, and so far as I can tell, they don't supply any details that one could use to verify that. I think that is likely a best case number, and typical is probably much worse, but there is no way to prove it.
If you've ever read about everything that is needed for modern oil production, it is hard to believe they achieve anything like that sort of efficiency.
Then there is flaring of natural gas. I'm almost positive they don't count that, since it doesn't go into making gasoline; it's a by-product. Still, if you're counting CO2 emissions, that really needs to be included whenever gasoline is burned. Again, actual figures from the oil industry are hard to find.
Then if you really want to get into it, a rising percentage of oil production is from the oil sands/oil shale/tar sands. Producing oil and ultimately gasoline from that stuff winds up producing two to three times as much CO2 as regular oil and gas production.
The figure I've seen before was that gasoline production is 85% efficient. That comes from the oil&gas industry, and so far as I can tell, they don't supply any details that one could use to verify that. I think that is likely a best case number, and typical is probably much worse, but there is no way to prove it.
If you've ever read about everything that is needed for modern oil production, it is hard to believe they achieve anything like that sort of efficiency.
Then there is flaring of natural gas. I'm almost positive they don't count that, since it doesn't go into making gasoline; it's a by-product. Still, if you're counting CO2 emissions, that really needs to be included whenever gasoline is burned. Again, actual figures from the oil industry are hard to find.
Then if you really want to get into it, a rising percentage of oil production is from the oil sands/oil shale/tar sands. Producing oil and ultimately gasoline from that stuff winds up producing two to three times as much CO2 as regular oil and gas production.
Well, they claim to be considering the whole production chain's emissions. The part I don't like is that they aren't specifying the driving conditions or the specs of the plugin hybrid. How many miles are being driven? What's the electric range? If they used the Volt's range and an average daily drive for the miles driven, I would think there would be no gas-based emissions in the chart for plugins at all. Changing either of those numbers can push the chart around in any direction you like, so the table is really just about arbitrary.
graham
Active Member
IBT comparison of of hybrids vs Roadster and Mini-E and claim the hybrids have lower emissions compared to the energy production used to create the electricity.
http://www.ibtimes.com/articles/20090220/electric-cars-emissions-problem-times-more-than-hybrids.htm
Of course their chart assumes that you are producing electricity using 100% coal. They mention in the text of the article that coal is less than half of what is produced in the US today, but didn't let that stop them from making their claims.
http://www.ibtimes.com/articles/20090220/electric-cars-emissions-problem-times-more-than-hybrids.htm
Of course their chart assumes that you are producing electricity using 100% coal. They mention in the text of the article that coal is less than half of what is produced in the US today, but didn't let that stop them from making their claims.
stopcrazypp
Well-Known Member
Funny how I just commented on autobloggreen this article http://www.autobloggreen.com/2009/0...or-widespread-electric-cars-will-take-15-mor/ that they tend to almost always assume 100% coal, even though it is very rare this will be the case.
I'll just redo a calculation I did but for lbs/100mi rather than grams/km:
35kWh and 104 mile combined range from the Mini-E spec sheet to get 33.7kWh/100 mile (this is to be fair since the brochure gives a 0.14kWh/km number for city driving only, rather than combined)
http://www.miniusa.com/pv_obj_cache...950647FC510200/filename/Mini-E-spec-sheet.pdf
Times 724lbs/MWh from my local power company (California PG&E) and I get CO2 Emissions of 24.4 lbs/100miles.
Using the US national average grid CO2 emissions of 1329lbs/MWh, I get 44.8 lbs/100 miles.
And keep in mind I am using the more "real world" combined driving number of 104 miles rather than 150 miles that they used in their calculations; if I used the 150 number the difference would be even more dramatic.
Obviously the results change drastically depending you using 100% coal, the national average, or sources cleaner than even the national average (like my power company does).
It's very easy to get CO2 numbers for your power company using the below link and compare it to the national average.
How clean is the electricity I use? - Power Profiler | Clean Energy | US EPA
Edit: Anyone a member at IBtimes? If there is, feel free to post the numbers I calculated there just to show the errors in their analysis.
Last edited:
Also, of course, they didn't include the energy it takes to produce the gasoline.
The only thing the article claims is that EVs - powered by coal - are roughly just as good as hybrids. I've read that elsewhere. It sounds like it's true. But we don't need to worry because only half our energy comes from coal.
In addition, most of the places where EVs would be most popular (California and major cities) are the places where energy production is cleanest.
The only thing the article claims is that EVs - powered by coal - are roughly just as good as hybrids. I've read that elsewhere. It sounds like it's true. But we don't need to worry because only half our energy comes from coal.
In addition, most of the places where EVs would be most popular (California and major cities) are the places where energy production is cleanest.
Last edited:
mt2
Member
Interesting.
I looked up my electric source mix and found that we're using 72.8% coal compared to the national average of 49.6%. There's also 2.7% natural gas in there, but the bulk of the remainder is nuclear.
So I did some simple back of the napkin math and just multiplied the CO2 emissions of the Roadster and Mini E by 75%. The Roadster showed 35.6 lbs/100 miles and the Mini E showed 39 lbs.
Hence, both beat out the the best hybrid, the Prius, even with our neighborhood grid being nearly 50% dirtier than the national average.
I looked up my electric source mix and found that we're using 72.8% coal compared to the national average of 49.6%. There's also 2.7% natural gas in there, but the bulk of the remainder is nuclear.
So I did some simple back of the napkin math and just multiplied the CO2 emissions of the Roadster and Mini E by 75%. The Roadster showed 35.6 lbs/100 miles and the Mini E showed 39 lbs.
Hence, both beat out the the best hybrid, the Prius, even with our neighborhood grid being nearly 50% dirtier than the national average.
stopcrazypp
Well-Known Member
Yeah, that's because they used the most ideal numbers for both the Roadster and the Mini.
The way I did it was using combined city/high range numbers which is how CO2 emissions numbers are supposed to be calculated.
I used 104 miles of combined range instead of 150 ideal max, so if I adjust your result for the 104 miles, I get 39lbs/100miles*150/104 = 56.25lbs/100miles
Which kind of makes more sense since you wouldn't expect to get lower numbers than the average when your area is clearly dirtier.
"This is what I got -except the word "good" get's replaced with "bad"."
Yes, but it is a good thing! Imagine a coal car as clean as a hybrid? Only an EV could do that.
Well, actually, there's an exception. Coal powered EVs are just as clean, and are cleaner in terms of most pollutants, but are dramatically higher in SO2. I think it's SO2, or some other nasty something. Then again, at least it's not being released directly in our cities.
Yes, but it is a good thing! Imagine a coal car as clean as a hybrid? Only an EV could do that.
Well, actually, there's an exception. Coal powered EVs are just as clean, and are cleaner in terms of most pollutants, but are dramatically higher in SO2. I think it's SO2, or some other nasty something. Then again, at least it's not being released directly in our cities.
