View Single Post
Old 04-28-2009, 05:10 PM   #28 (permalink)
Jim Bullis
EcoModding Lurker
Join Date: Jul 2008
Location: California
Posts: 80
Thanks: 0
Thanked 2 Times in 2 Posts
Lets be fair!!!???

Hi Ernie,

I first noticed your headline and my reaction was someone was thinking that EVs were not getting a fair shake in the mpg game. Quite the contrary, it was you in control. (I was sorry to see that Ken Fry seems to have given up his reform efforts in the face of the XPRIZE final rule determination.)

Glad to see you are still a strong force for technical sanity in the "eco" or "green" world. I am convinced that there are few in this world who stayed awake during freshman physics class.

However, I have firmed up my position that the efficiency of coal fired power plants is the governing process efficiency for all plug-ins in USA or any country where the use of coal is not serverely penalized. This efficiency is 33%. Of course, the whole thing is nonsense when it comes to MPG, equivalent or not, since it just can not be upheld in logic, like adding apples and oranges.

It is more important to convert to CO2 emissions. This can be done with some rationality, though usually it is not.

The first question asked is, "What is the mix of power sources?" I maintain that this is irrelevant since only the lowest price source is relevant. All the more desirable forms of production are fully tapped out, and are not available to respond, regardless of who or how they get on line. I now realize that even California, which basically bans coal, is subject to the lowest priced source rule due to economic coupling through the natural gas market.

Economic coupling takes place when California turns off a coal plant and turns on a natural gas plant in its place. The impact of this is an increase in demand for natural gas, though slight, it is a national impact. That increase in natural gas demand would first be felt as a price increase in natural gas; however, as the rest of the power producers of North America sense such a price increase, they will be immediately motivated to increase their use of coal. The price of natural gas will then be returned to its previous equilibrium price. And that increase in the use of coal, any- and every- where in North America, will be the impact of that EV load.

So the CO2 calculation has to proceed on the basis of 33% efficiency as well as the 2X factor of coal CO2 per BTU compared to natural gas. Sure, thrown on 10% for coal transportation since that requires more energy than natural gas transportation. (If you have a better number I would defer to that.)

After all this, the electric vehicle still has merit as an efficient system where regenerative braking is made possible. The hybrid is the better way to make this work than the plug-in. And maybe more importantly, where the electric machinery enables a much more efficient car it is quite another matter. There is nothing bad about a car running on coal fired power if it uses a small fraction of the power that otherwise would be needed. So making the overall car into a low user of energy seems far the better action.

Any progresss in low rr tires?
  Reply With Quote