jpt

Hydrogen is efficient from the LH2 tank to the wheels (about 1/3 more efficient than gasoline), but at the moment it's horrendously inefficient in the hydrogen-manufacturing plant. The energy costs of producing hydrogen are about twice the cost of the energy it contains, and then that cost is about doubled again when you account for transportation. 1kWh of hydrogen using current manufacturing and transportation technologies (even assuming we could build all the pumps and storage tanks for free) would cost about 3 times as much per kWh as gasoline (Pimentel, 1996, in a study that has been blasted for artificially inflating the reported cost of gasoline).

But the biggest (pun intended) problems with hydrogen are storage considerations. A hydrogen tank equivalent to a 10-gallon gas tank would have to hold 40 gallons and weigh over 150 lbs (this is AFTER accounting for the increased efficiency of a hydrogen-powered car). It would furthermore need to be more complicated and fragile than a gas tank, as it'd need a double-layer mirror-finished construction (like a Thermos) to minimize evaporative losses. Even with those precautions, if the car is to be stored for an extended period of time you'd need a battery or an auxiliary gaseous-hydrogen tank to be able to get you to a filling station.

For these reasons the best practical examples of hydrogen powered vehicles i've seen in actual use are big city busses -- they have plenty of space on the roof to store a huge tank, they're driven most of the day every day, and they get much, much more of a win (for us) out of a cleaner engine even if it's not more energy- or cost-efficient.

jpt

Minimal effect on performance if you're already driving a crappy (mechanically-injected) diesel engine, right?

Even still, this is a cute gimmick and a nice cost-saving measure for frippies, but we don't waste nearly enough fry oil to power all the cars in the country.

moda_way

Understood, but then hydrogen production wouldn't have the same efficiencies as petroleum has because it is primarily used for industrial purposes.

moda_way

TSX 04 Mirror (non-heated)
76253-SDA-A21
H: 15mm L: 177mm W: 107mm

TSX 05 Mirror (heated)
76253-SDA-C42
H: 15mm L: 167mm W: 106mm



Accord 05 V6 4DR
76253-SDA-A11
H: 25mm L: 177mm W: 139mm

bradykp

ummmm....mcdonald's, burger king, wendy's, arby's, long john silver's, white castle, checkers, etc etc etc, all have to pay to dispose of their oil, they'd be glad to give it away, and i think they waste a lot. it wouldn't power all the cars in the country, but with our fat-ass consumption rates of fried food, it'd do a pretty good job.

it's funny how these things are always discounted as hippie solutions. doing good things for the environment is such a huge inconvenience on us, i know.

moda_way

WTF was I posting here. LOL

gpsiir

Yes. Adding the hybrid technology that Honda has developed to our engine would be awesome. Only down side I can think of is that the hybrid Accord/Civic use the back of the rear seats for batteries, so no fold down rear seat.....

Adrena

Yes - If it drives the same way or better.