The attractiveness of hydrogen lies in the variety of methods to
produce hydrogen as well as the long-term viability of some of
them (from fossil fuels, from renewable energy: biomass, wind,
solar [5], from nuclear power etc.), the variety of methods to
produce energy from hydrogen (internal combustion engines, gas
turbines, fuel cells), virtually zero harmful emissions and potentially
high efficiency at the point of its use. Compared to biofuels,
a recent study reported the yield of final fuel per hectare of land for
different biomass derived fuels, and of hydrogen from photovoltaics
or wind power [6]. The results show that the energy yield of
land area is much higher when it is used to capture wind or solar
energy. Compared to electricity, using hydrogen as an energy
carrier is advantageous in terms of volumetric and gravimetric
energy storage density. However, there are also serious challenges
to overcome when hydrogen is to be used as an energy carrier.
Although better than batteries in storage terms, its very low density
implies low energy densities compared to the fuels in use today,
even when compressed to 700 bar or liquefied, both of which incur
substantial energy losses. Thus distribution, bulk storage and
onboard vehicle storage are heavily compromised. Also, in case of
hydrogen-fueled vehicles, care must be taken to ensure that the
well-to-wheel greenhouse gas emission reduction compared to
hydrocarbon fuel turns out to be positive [7]. Nevertheless, the
advantages offered by hydrogen are significant enough to warrant
the exploration of its possibilities