comparison of various automotive energy sources

Post by **Jonathan** » Fri Apr 15, 2005 12:58 am

I was curious, so I looked it up.

NiMH battery - 1 MJ/l
Hydrogen (gas@5000psi) - 3 MJ/l
Hydrogen (liquid) - 8 MJ/l
Gasoline - 32 MJ/l

The numbers change when you factor in the storage technology overhead, but the ratios are still about the same.

Hydrogen is much more energy dense than gas when you compare by weight, but weight doesn't seem to be the limiting factor. Volume does.

NiMH batteries are what the Prius has in it. GM has a 10,000psi compressed hydrogen van and a liquid hydrogen van. Their fuel cell is 1.6 kWh/l, or 5.5 MJ/l.

http://www.gmeurope.com/marathon/2/popu ... liquid.htm
http://www.gmeurope.com/marathon/2/popu ... ressed.htm

The liquid hydrogen van has a range of 250 miles. The main problem is making the tanks big enough and cheap enough on a production car.

Costwise, my calculations suggest that hydrogen will be about the equivalent of paying four bucks per gallon of gasoline, assuming you do coal-powered electrolysis. If you get your hydrogen from methane or do your electrolysis with cheaper energy, that number goes down.

Peijen · Post by **Peijen** » Fri Apr 15, 2005 1:32 am

where is nuclear power?

quantus · Post by **quantus** » Fri Apr 15, 2005 1:47 am

The van shuttles at the airports here are all required to be hydrogen powered from what I found out. It's kinda annoying since they now charge like $20 or $30 more

Martin · Post by **Martin** » Fri Apr 15, 2005 3:37 am

quantus wrote:The van shuttles at the airports here are all required to be hydrogen powered from what I found out. It's kinda annoying since they now charge like $20 or $30 more

Pretty sure you mean compressed natural gas.

Post by **Jonathan** » Fri Apr 15, 2005 4:30 am

Nobody cares about nuclear energy density because nobody proposes using it in volume or weight constrained systems like personal vehicles. Given E=mc^2, I would assume it is a bunch.

quantus · Post by **quantus** » Fri Apr 15, 2005 5:46 pm

Martin wrote:
quantus wrote:The van shuttles at the airports here are all required to be hydrogen powered from what I found out. It's kinda annoying since they now charge like $20 or $30 more
Pretty sure you mean compressed natural gas.

I stand corrected. Thanks for the link, I've been meaning to look that up.

Post by **Jonathan** » Wed Sep 07, 2005 6:34 pm

http://www.amminex.com/index_files/Page344.htm
http://www.dtu.dk/English/About_DTU/New ... C2CF1A7%7D

Hey hey hey! 13 MJ/l! I'll buy a car running on that.