Quote:
Originally Posted by NeilBlanchard
Hmmm.
Seems to me that almost 75% of petroleum energy used for transportation is wasted; compared to ~68.4% wasted in electricity.
|
I do not see where you got %68 at all for electric transportation. (or %75?)
petrol dominates transport, so lets say the product to waste ratio is: 6.74/20.23 or %33.3 efficient at doing work. That is business as usual, averaging the good and the bad. There isn't enough electric signal there to make any speculation about 68.4%
So we have two conversions to consider for electricity. First conversion is the 12.08/26.1, or %40 efficient, without having done any work.
If the stationary homes/industry/commercial are doing mostly things like heating, then the fuel use is going to be very efficient. Those three all rate 80% efficient, regardless of the mix of electric/fossile (possible red flag?) so it isn't a good basis for comparing to transportation (and we want to compare to petrol in transportation because we have petrol pretty well isolated in transportation, and this is a car site).
So we know that electricity from the wall can charge a car, the question is how efficient is that once you do some work.
Well, I think that saying electric cars are %70 efficient is terribly generous, especially "on average", even more so if it includes charging. Remember the goal isn't heat here, it is much more complicated. Regen is a separate issue.
So the two conversions multiplied to gether, %40 x %70, = %28 efficiency for electricity in vehicles. Compared to %33 for petrol transportation. Even if the transportation conversion step was %80 efficient for electricity, that would only be %32 efficient, still less than petrol overall (not counting wars and yadda).