Thats interesting.... There are other sites that actually have more sited research... Hydrogen-boost.com. I wouldn't worry about the power drain... As far as I am aware the alternator works as hard as it always does based on the RPM of your engine. And if you are worried about it just lose your smog pump and put in a second alternator with a dual battery setup.
Apparently the idea came out of some research from Nasa in the 70s (there system was solar powered). Here is some good information from a reputable source:
http://www.greencarcongress.com/2005...mment-11093310
There is also a video on youtube about building your own fuelcell... I might try it out. Most certainly I think you will need to recurve your timing to take advantage..
john