Coal power Volt vs. Gas power Prius

Blah, blah.
And we are gonna have a "nicely under $30k" Volt that consumes 200 wh/mile, too. Right around the time that all coal plants magically sequester CO2. Enjoy your fantasies in la la land, I'll continue to post facts.

Fact: overall thermodynamic efficiency of the US coal grid is about 32%. Courtesy of the US EIA.

 

More from the US EIA:

U.S. Coal Supply and Demand
2009
1073 million short tons mined
936.5 million short tons consumed by electric power plants
45.9% of electricity produced is from coal
US consumption: 4 x 10^12 kwh
(3)*(4) = 1.836 * 10^12 kwh electricity from 935.6 short tons
Short ton is 1995.806428 pounds
so ... 1.99580*936.5 pounds -> 1836 kwh
One mined pound is 0.982308443 kwh at the meter

Cool, lets calculate CO2 intensity starting from 1 kwh/pound:
Commerical coal is 70 - 80% carbon -- I'll calculate from 75%
C -> CO2 is 44/12, so 1 kwh from coal is 0.75*44/12 = 2.75 pounds of CO2, or
If we say a Volt can go 3 miles on a kwh, each mile is 0.916 pounds of CO2
* Somewhere keep in the back of your mind that 3 miles/kwh is in temperate weather. Consumption will climb dramatically in the cold winter for the EV, but much less so for a Prius because then the powerplant is acting as a CHP.

How does that compare to a Prius burning petrol ?
A gallon of petrol consumed is about 20 pounds of CO2, and the Prius moves about 50 miles. Well to tank processing eats up 12% So each Prius mile is 0.4/.88 = 0.454 pounds of CO2

Result: A Volt spews out 100% more CO2/mile than a Prius when the source fuel is coal.

 

Lets agree on facts instead of this silliness. My point is it if you consider pollutants and economics phevs and bevs are part of our energy future. SO2 and NOx are capped so more demand on the grid does not increase these, it only increases costs to the pouting plants that must pay more for credits. This is part of the greening of the grid. A prius has extremely low levels of these, so the extra pollutants just aren't worth talking about. Cars for the next couple of decades will only be a small percentage of the grid. If it is too dirty for cars, it is also too dirty without cars. All resources are not created equal. If I am 2% efficient burning methane off of sewage to power my car it is still better than 200% efficient on gasoline. Don't assign only coal to the evs, and if you include the cost of energy production and distribution which we should, you should include the costs of refining.

I believe that was John mainly purporting that myth. I said exactly the opposite. Someone found a quote that before the volt made it out of show car stage that was the goal. If you believed it from john blame him, but please do not pretend I said this.

I gave the time line of the german government and I believe it is realistic and will happen. No magic, it takes money and replacing the old coal plants. This is also something we should be doing in the united states.

I never quarreled with your correct facts. I do however feel that I should correct you when you post distortions of what I write.

See, I even left the 20% in my post for the worst plants, I didn't even check the number, since we should get rid of the worst plants. This provides a great opportunity, since we measure up so badly. If 32% coal plants get replaced with 46% efficient coal plants and 60% efficient natural gas plants we use much less fuel and produce less ghg even without ccs and renewables. With the newer more efficient plants it is more economical to add ccs. New plants add new costs as the old plants are paid for and coal is cheap. If cap and trade tightens pollutants and we add cap and trade for CO2 we can accelerate the improvements.

 

A favorite Israeli saying of mine, translated:
"IF my grandmother had many wheels, she would be a bus."

She does not. Your conjecture plus a penny is worth a penny.
Just for my amusement though, you anticipate the US congressional republican, tea party, and libertarian blocs to vote for carbon cap and trade soon ?

OK, enough laughter. Back to facts and figures *as they exist.*

 

Ok ... I'll use the big red numbers as a (theoretical or actual) given. Now if we go back to the "50% of electricity comes from Coal" issue, consider how some states use more coal, and some use less, and so you get 50% average. From maps I've looked at, many of the heavily populated (people AND cars) states in the US (like Calif) often use less coal. Perhaps the good thing is that in the areas where there will naturally BE more EV's & PHEV's getting used (due to more cars being there) ... there will also be less coal used in those areas. So, just because electricity comes 50% from dirty coal ... doesn't necessarily mean 50% of the EV's & PHEV's will be getting their electricity for a 50% ratio state.



It looks from these charts like Texas & Ohio are worse, as far as coal/population ratios go ... New York & CA seem to belch the least coal. (If you don't count how much coal power CA gets from AZ)



.

 

wjtracy,
please note corrections to my calculation. I come up with the Volt emitting 100% more CO2/mile than the Prius in temperate driving conditions, not the 229% I originally posted. I know that sounds like a nasty error, but most of it is the difference between writing in English "more than" and "fraction of."

2 is twice 1, but 100% greater than 1.

 

Hill, I think you are discussing the weighted fraction of coal use in an EV. A number of good research articles have been published on this topic, so far as I remember all the recent publications are based on DOE's GREET model. May I suggest starting with

Elgowainy, A et al published June 2010. "Well-to-Wheels Analysis of Energy Use and Greenhouse Gas Emissions of Plug-in Hybrid Electric Vehicles." If you are the type that likes to look a a picture for an executive snapshot of things, click on the thumbnails. Note two things: as the fraction of EV/petrol miles increases, so does GHG/mile; second, things get worse as 'smart charging' is utilized. 'Smart' is the power utility label for increased coal use.

A longer list of GREET based studies from Argonne.

 

and co2 is not the problem if you want clean air look at other stuff that i think is more important like NOx

also is anywone thinking about the energie total needed for that guel to get to the car and the coal to get to the powerplant!
its the total number thats going to make the change!

 

Read up on the GREET model. Those energy inputs are included.

 

The latest from Elgowainy, June 2010.
I cannot remember if the presumed GM Volt efficiency was the early hype or the later reality.

Volt Vs Prius:
In NG dominant regions about the same GHG/mile, ~ 10% less if "smart" charging avoided.
In Coal dominant regions Volt has 1.57 times the GHG/mile.

 

A cordless hybrid is hard to beat in GHG emission.

 

what if the hybrid is burning petrol derived from tar sands? Also, what's the population balance between NG dominant and Coal dominant? Also, the carbon intensity of the grid is falling, the carbon intensity of oil production is increasing. Are the current crop of EV eque vehicles perfect? No. Do they have a better upside than Hybrids? Yes. Why do we keep beating this dead horse?

 

I get 100% green energy. Anyone getting clean oil ?

Marginal electricity can be wind, BTW. Because of excess generation at night they are not fully used. Ofcouse marginal oil comes from tar sands.

 

Hi Tripp,

If the fuel source is tar sands then the w-t-w calc should reflect it, in proportion to the total oil obtained that route.

A drop in the overall carbon intensity of the grid does not matter, if the fuel sources to supply the marginal demand added by EVs remains dirty. This is actually my most important point -- that national interests (read:money) should be directed towards the grid and clean energy, and not subsidy of consumption appliances that simply substitute petrol for NG/coal.

Are current EVs perfect ? Nothing is perfect. A fairer question that EV advocates refuse to consider is: are they better than (smart) petrol alternatives now ? In the next 5 years ? In the next 10 years ? As public policy I answer no, no, and no. This is why the discussion is not a dead horse IMHO.

Lastly, is it smart to switch from international oil to domestic coal and NG, knowing that the latter brings air and ground pollution home ? I honestly am torn on that point, but I am sure it deserves discussion. I could support NatGas as a short term grace to solar and wind, but coal is a bitter pill to swallow, if not outright poison.

 

Most people keep their car for 5 years. A typical end of life for a car is 10 years. A new redesigned model come out every 5 years.

Therefore we should look at the next 5-10 years to forecast GHG emission and make it part of the purchasing decision. Prius PHV with smaller battery makes the most sense. You want to be part of the solution, not pollution. That basic green criteria was ignored by GM when designing the Volt. Leaf is a good enough solution that is a bit premature.

In 5-10 years do you think our grid electricity will be significantly cleaner?

 

US new car sales are about 15 million a year averaged over the past decade, and the fleet is about 250 million vehicles. Average car life then works out to 16.6 years.

However, given my lack of confidence in EV batteries and GM I'll agree with your 10 year timeline in the case of the Volt.

 

As far as I know, the only way to make the situation better is to first figure out what paths can lead to a better situation.

I cannot figure out how to make a non-polluting vehicle power infrastructure using gas propulsion on vehicles. I cannot do this either for natural gas. Can you?

I can see a path with electric vehicles. It's two interlocked steps. One step is electric vehicles. The other step is sustainable electric energy production.

After that it is a very critical step of execution. One execution step underway is developing the electric car manufacturing needed. Something that will take decades. The other execution step needed is sustainable electric generation. Something that will take centuries. But both have started and can use as much support as I can give.

 

I have thought about this argument and I do not dismiss it out of hand, although I do not support it for a couple of reasons.

First, a clean grid is paramount, is not dependent on EV, and is hindered by resources that flow to EV instead of clean energy production and grid improvement.

Second, I think it is a bad idea for government to choose technology winners and losers; their track record is worse than terrible. Although my crystal ball says EV for public transport, I'll happily choose E-trains instead. Or maybe a Segway derivative, or something I cannot imagine today like personal maglev.