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Re: [Phys-l] not-anywhere-near-zero emission car



I am reminded of the saying: A politician who robs Peter to pay
Paul can count on the support of Paul.

We really ought not call hydrogen cars zero-emission cars. At
best, they are elsewhere-emission cars. Or you could call them
robbing-Peter-and-several-other-people-to-pay-Paul cars.



On 07/14/2011 05:53 AM, Kyle Forinash wrote:
Fuel cell cars will be a good idea when we find a way to make hydrogen
more efficiently. Currently we get nearly all of our hydrogen from
natural gas at a 40% energy loss. Energy wise it makes more sense to
burn the natural gas in a combustion engine than turn it into hydrogen
for a fuel cell car.

Quite so.

Even if you imagine some future world where the hydrogen is made
from something renewable, such as solar photovoltaic electricity, I
still don't see any way that hydrogen cars make sense, because they
would be squeezed from both sides:
-- On one side, they would have to compete with battery-powered
plug-in cars. The distribution of electricity is probably always
going to be more convenient than the distribution of hydrogen.
-- On the other side, in applications where power density matters,
such as aviation, hydrogen will never compete with hydrocarbons,
including biodiesel.

An interesting spreadsheet that you can download from Argone National
lab allows you to calculate well to wheels energy for several
alternative car engines (ethanol, fuel cells, etc.):
http://greet.es.anl.gov/