Technology Status of Hydrogen Road Vehicles

! Cryogenic GH 2 is still in the R&D phase, and needs thermal management
! Micro-sphere GH 2 is still in laboratory phase
! LH 2 is good but expensive
! Slush (half solid, half liquid) has 15% higher density than LH 2, but is too difficult
! MH is safe, but needs thermal management, and impurities are problematic
! Organic liquid hydrides (methanol, LNG, MCH) are good if direct use is feasible.
Yamane, K.; S. Furuhama, “A Study on the Effect of the Total Weight of Fuel and Fuel Tank on the
Driving Performance of Cars,” Musashi Institute of Technology, Tokyo, Japan, pp. 1053-1062.
Using simplified equations, a parameter study was performed to find the influence of total weight of fuel and
fuel tank on fuel economy, range, starting and running accelerations, maximum grade, and maximum vehichle
speed.
The influence is quite strong, and as far as the various hydrogen options (300 bar GH 2, MH, LH 2) and a battery
EVs are concerned, LH 2 is much superior for driving range and fuel economy. They concluded that to satisfy
the necessary conditions, and therefore an acceptable weight of fuel and fuel tank, only LH 2 provides a
practical solution.
Michel, F., et al., “Onboard Equipment for Liquid Hydrogen Vehicles,” Messer Griesheim, Cologne,
Germany, pp. 1063-1077.
This paper shows how on-board LH 2 storage tanks have improved during the past 20 years: doubling of energy
density, and nine times less evaporation rate; in fact, today, no evaporation losses need occur for several days.
The authors also report on the improvements of several detailed components that influence the safety and the
fuel supply.
The safety tests were done together with BMW (see Pehr [1996]).
An example of new components is a device for pressure control of LH 2/GH 2 fed to the engine: a special metal
hydride in the insulation space of the cryotank. By varying the heating to the hydride, more or less gas is
formed, changing the heat transfer and therefore the pressure in the inner tank.
Another device maintains a constant low temperature of the cold GH 2 to the engine; if this temperature is too
high an ICE suffers power loss; if too low the heat source (engine cooling water) can freeze.
Ogden, J.M., “Development of Infrastructure for Refueling Hydrogen Engines,” Princeton University,
New Jersey, USA, pp. 1113-1122.
If mandated levels are imposed, the Los Angeles basin will have several 10 5 ZEVs by 2010.
This paper assesses the economics of various near-term possibilities for producing and providing GH 2 for
urban transport vehicles, and how a refueling infrastructure might evolve during the next few decades.
Conceptual designs of refueling stations and delivery systems were established for each of five major options,
in each case supplying 100–1000 cars or 200-300 buses/d for a total per station 0.1-2 million scf/d. The five
options are:
1. NG/LH 2 ; truck LH 2 ; store/vaporize ; fuel vehicle.
2. NG/GH 2 ; pipe GH 2 ; compress/store ;fuel vehicle.
3. Refinery GH 2 ; pipe GH 2 ; compress/store ;fuel vehicle.
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