Wednesday, March 21, 2012

Casebook - The Case of the Missing Tailpipe

So is the Leaf a case of no tailpipe or long tailpipe?

Clearly a gas powered car emits CO2 and other emissions as it burns, newer efficient cars producing less directly.  Now with catalytic converters with rare metals stopping more smog components then in the seventies.  However electricity clearly comes from somewhere - what about plant emissions?

A 9/22/11 US Department Of Energy study says mile per mile the Leaf is 60% less emission if we include the electric plant.  That is NOT including all the oil well to wheels emissions for oil/gas.  Just burning the gasoline on the car side.  So if my Honda puts 10 lbs of CO2 and I put out 4 lbs from the electric grid generation for the same driving - is that worth it?  I'd say so.

It gets better though.  For one thing I can replace the grid with solar panels at home - many Leaf owners have.  Solar costs have been dropping like crazy.  The standard electric grid though tends to be getting cleaner and more renewable with time.  It's centralized - clean up single problem plants and big gains result.  The most dirty source - US coal, is about 49% of the Maryland grid which is similar to the US average.  That source, as is most production of US electric, produced by US resources.  Some Canadian hydro as well.  So my vastly cheaper electric bill payment is staying stateside.  Not headed to OPEC.

Finally remember all unexamined cost of oil to gas to the pump that we have let stay hidden?

Lets examine just one - refining oil to gasoline.  The best estimate I can find is it takes 6kwh of energy to refine oil into a gallon of gas.

Right now my Leaf is averaging 4.1 miles per kwh (I've been driving less crazy lately - it was 3.8).

So *before* that gallon of gas is transported, stored, pumped in the tank - when it's *made* at the refinery.

I've already driven 24.6 miles.

When the leaf is paid off in five years and I'm still 3-5 years away from battery replacement, that's when I'll look at a small maybe 2kw solar setup.  Then I'll be driving on sunshine.

Electric cars win on this one.


Apologies to the insanely great Firesign Theatre and Nick Danger.

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