View Single Post
Old 07-02-2013, 08:05 PM   #53 (permalink)
Master EcoModder
Join Date: Jun 2008
Location: Earth
Posts: 5,209
Thanks: 225
Thanked 811 Times in 594 Posts
Originally Posted by ConnClark View Post
The efficiency of 33% is the efficiency of a typical Rankine cycle power plant (where most electricity is generated in the US).
Not if you look at actual data. Yes, there are some older plants at about that level. Newer coal-fired plants are closer to 40%, while a combined-cycle gas turbine plant can be about 60% efficient (per Wikipedia: Gas turbine - Wikipedia, the free encyclopedia )

Furthermore, since there is no way to know where any particular bit of electricity is coming from, you need to look at the whole grid. With 20% nuclear and maybe 10% hydro & other renewables, that boosts the overall grid efficiency (of fossil fuel -> electricity) to the 50% range.

Second, IC engines as used in typical passenger vehicles aren't anywhere near 33% efficient, because they are almost always running far from their optimum BSFC.

Third, re lithium and "rare earths". Lithium is fairly common, and readily mined & recycled (far more so than petroleum!), and as someone has already stated, you need only a few pounds per vehicle, vs many tons of gasoline consumed over a vehicle lifetime. So-called rare earth elements actually aren't all that rare, either.

Just for interest, my Insight gets about 70 mpg. In 140K miles of driving, that's 2000 gallons of gasoline, about 6 tons. Since only about 30% of crude oil can be converted to gasoline, that's close to 20 tons of petroleum burned over a modest automotive lifetime.
  Reply With Quote
The Following 4 Users Say Thank You to jamesqf For This Useful Post:
NeilBlanchard (07-03-2013), Pawtuckett (07-03-2013), RedDevil (07-03-2013), redpoint5 (07-08-2013)