[Wonder Warthog]

"Running a car is a transient process and you've got to have a pretty big fuel cell to power it, something on the order of 50kw as opposed to a 5kw cell to power a house, for instance."

BS ALERT!!! BS ALERT!!

Not true. The fuel cell only needs to be big enough to provide power sufficient to provide maximum estimated desired continuous speed. "Transient processes" (passing acceleration) will be handled by a BATTERY, which will be charged by the fuel cell during periods when the car is running at less than maximum cruise speed.

[SunkenCiv]

So, IOW, it's not BS, you'd just solve that particular problem differently. Driving a car is not generally a matter of cruising at a fixed speed, and that's what he's referring to.