Table 3: DOE hydrogen storage targets for light-duty vehicles [41].

Storage parameter Units 2010 2015 Ultimate target

Gravimetric system density kWh kg−11.5 1.8 2.5
MJ kg−15.4 6.48 9
wt.% 4.5 5.5 7.5

Volumetric system density kWh l−10.9 1.3 2.3
MJ m−33.24 4.68 8.28
 l−128 40 70

Fuel cost at pump $ 3–7 2–6 2-3

System filling time for 5 kg H2min 4.2 3.3 2.5
 min−11.2 1.5 2

Maximum loss of useable H2g (h  )−10.1 0.05 0.05

1 gasoline gallon equivalent (GGE) 1 kg hydrogen [43].