Max,

Sunline Transit in CA, used off peak wind power, form the Beaumont Pass/Palm Springs wind catchment, along the UP and I-10, to make hydrogen from good old fashioned water, making it one of he few "cost effective" hydrogen fuel cell bus/tractor pulled passenger vehicle demonstrations in the US from the perspective of fuel cost. Hydrogen at present "commercially available" costs, is nowhere near the BTU per "gallon" of energy density of "diesel equivalent" or CNG equivalent costs, it is still something like four or five times the cost.

Although, I am intrigued by the possible comparative energy output between combustion hydrogen and fuel cell hydrogen in terms of thermal efficiency delivered?

Sunline also used the excess hydrogen to make "hythane" from natural gas to a 20% mixture, without having to replace all of the CNG bus fuel systems with high corrosion resistant components (hydrogen is kind of like it's pal oxygen in wanting to bond with everything). And, they expected a hotter burn would produce more nitrous oxides, but, the combustion produced so much steam that it actually absorbed heat, and cooled the burn, producing less NOx emissions on the busses.

I was wondering if these hydrogen "HMU's" were using combustion or fuel cells,, so thanks for answering that question for me, and was wondering how much vehicle space we are talking about for this battery/fuel cells? How does that affect vehicle capacity? And, how are they dealing with fuel storage and safety. Tanks up on top for safe (light than air) venting in case of breach? Or "the mother of all" crash proof pressure tanks? Or, something else? And, thanks for the performance information. It's an interesting demonstration, especially the fuel cell application....leading edge, or bleeding edge?