Page 21 - Introduction to Transfer Phenomena in PEM Fuel Cells

10 Introduction to Transfer Phenomena in PEM Fuel Cells
1.1.3. Distribution networks and associated risks
Currently, the industrial distribution process used is to produce hydrogen
in centralized units, then use it on site or transport it by pipelines.
Pipeline gas transportation connects major production sources at the main
points of use. Hydrogen distribution networks via pipelines already exist in
various countries to supply the chemical and petrochemical industries.
Implementing these industrial infrastructures shows that one has a good
control of the generation and the transport of hydrogen.

One caveat however: the transport cost is about 50% more expensive than
that of natural gas and a unit of volume of hydrogen carries three times less
energy than a unit volume of natural gas.

To distribute hydrogen, refueling infrastructures will have to be
developed. The development of service stations does not appear to pose any
particular technical problems. A total of 40 pilot stations already exist in the
world, mainly in the United States, Japan, Germany and Iceland. However, it
will take time for these service stations to cover the entire territory that
requires this fuel, which could slow down its development in transport. To
overcome this difficulty, some car manufacturers are considering using fuels
that contain hydrogen rather than hydrogen alone. In this case, the reforming
step takes place on board the vehicle. This process then becomes less
interesting since this reforming produces carbon dioxide, the main cause of
the greenhouse effect [CEA 18].

The accepted idea is that “hydrogen is more dangerous than traditional
fuels”, this assumption needs challenging. Of course, like any fuel, hydrogen
can ignite and/or explode in case of leakage. Nevertheless, to compare the
danger levels of traditional fuels and hydrogen, the nature of the assessed
risk should be discerned [CON 18b].

1.1.3.1. Risk of leakage
The small size of the hydrogen molecule allows it to escape through
extremely small openings. The risk of leakage is therefore higher with
hydrogen than with other fuels.