Quote:
Originally Posted by BigRigMike
Using your numbers electric power is 51% efficient and internal combustion is 18% efficient. Sounds pretty good to me.
If you assume you start with 1kw equivalent of coal
Power generation 1 kw * .75 = .75 kw
Transmission .75 kw * .95 = .7125 kW
Battery Charge .7125 kW *.8 = .57 kW
Discharge .57 kW *.9 = .51 kW
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Actually I made a typo in the original post.
It's a long story but I had typed in a much more detailed breakdown of the numbers right down to drag losses and accessory losses I got from the EPA site. I went to submit it and the site kicked me back to the "login" screen and when I logged in the post was lost and hitting "back" didn't get me back to the post I had typed in over an hour.
The actual numbers I had gotten for power generation was roughly 25% EFFICIENT. The site I had googled said 75% loss and I mistakenly flipped it to 75% efficient. The real number is that electrical power generation is 75% Loss... or 25% efficient.
The most efficient source of power generation is hydroelectric which only has about 10% losses (90% efficient), but since only about 10% of electricity in the USA comes from hydro plants, the impact is not that great. Most people get their power from horribly inefficient sources like coal burning and whatnot.
My original calculations put electricity at 18.5% efficient for cars and the number I got from the EPA for Gas was 18.2% efficent. A wash.
Pure Electric cars just don't cut it.