comparison of various automotive energy sources
Posted: 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.
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.
