Environmental Engineering Reference
In-Depth Information
13.1 Hydrogen as an Energy Source
Hydrogen is by far the most common component in our solar system and constitutes
around 75% of the mass and more than 90% of all atoms. Our sun and the large gas
planets Jupiter, Saturn, Uranus and Neptune consist primarily of hydrogen. Here on
earth hydrogen occurs much less frequently. Its share of the total weight of earth is
only about 0.12%. Although hydrogen occurs more frequently in the earth's crust,
it practically never occurs even there as a pure gas. Hydrogen is almost always
chemically bonded. The most frequent compound is water.
Hydrogen is the smallest and lightest atom. As an extremely light gas, hydrogen
was used to fi ll the gas bags of airships like the Zeppelins during the fi rst half of
the nineteenth century. The Hindenburg disaster, where an electrostatic charge sup-
posedly caused the hydrogen to ignite, brought a tragic end to the prospects of
hydrogen use.
The main application of hydrogen today is in the chemical industry. As an energy
source it is currently used on a large scale mainly in the aviation sector and in
space travel. Hydrogen has occasionally been used to drive the jet engines of aero-
planes. In space travel liquid hydrogen is used as rocket fuel. For example, the
launch of a space shuttle consumes about 1.4 million litres of liquid hydrogen
weighing more than 100 tons. This is burnt along with the 0.5 million litres of liquid
hydrogen that the shuttle carries with it. The combustion temperature is up to
3200 ° C (Figure 13.1 ).
Figure 13.1
Hydrogen is by far the most common element in our solar system (left) and is already
being used as an energy source for the launch of space shuttles (right).
Graphic/Photo: NASA.
