Quote:
Originally Posted by roflwaffle
I don't think I'd say it's gone horribly wrong, just that something with a motor is more efficient at using energy it has onboard than something with an engine. From the point of view of the EPA ratings someone isn't going to factor in average electricity generating efficiency just like they don't factor in gasoline production efficiency. Neither or those are what the EPA mpg rating entails. Someone could do that, but in that context what's more appropriate is Carbon emissions per mile, which I mentioned earlier in the thread.
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With liquid fuels it is figured in. For every X gals extracted from source Y, Z number of gallons is used in purification, processing, transportation etc. The 1 gal in your tank started as 1.X gal.
It's the reason alcohol from cellulose is impractical. It takes more energy to produce than it provides to the tank.
Quote:
Originally Posted by dcb
Let me try to pare it down a little, and this example still makes electrics look good.
Tesla lists itself as 135MPGe, which is inconceivable in a gas car with those performance figures. "Obviously" something has gone horribly wrong here in the comparison of electricity to gasoline, can we agree on that?
Now figuring out the exact numbers to use is a laborious process. But if we borrow the well(plant?) to "pump" efficiency numbers from the Department of Energy, %30 electric/%83 petrol, we get an adjusted mpg of 48MPG.
This still makes the tesla something to drool over, and 48MPG is certainly a lot more believable equivalence number than 135MPGe.
Does that reasoning make sense?
Note, I'm not promoting petrol, just trying to establish a fair basis for comparing the alternatives. |
Good example.
Or in fantasy terms :
If they made a 6cyl version of a VW TDI, say 3L range and put it in a roadster.
48 MPG would be reasonable for an average non-hypermiling driver. It would also have similar performance numbers.
Oh, and the one in my driveway would smell like Fried food
Rats, just looked out the window,......back to reality........