Environmental Engineering Reference
In-Depth Information
PROPERTIES OF HYDROGEN
Hydrogen has unique physical and chemical properties that present benefits and
challenges to its successful widespread adoption as a fuel. Hydrogen is the lightest
and smallest element in the universe. Hydrogen is 14 times lighter than air and rises
at a speed of almost 20 m/s, 6 times faster than natural gas, which means that when
released it rises and disperses quickly. Hydrogen is also odorless, colorless, and taste-
less, making it undetectable by human senses. For these reasons, hydrogen systems
are designed with ventilation and leak detection. Natural gas is also odorless, color-
less, and tasteless, but a sulfur-containing odorant is added so people can detect it.
There is no known odorant light enough to travel with hydrogen at an equal disper-
sion rate, so odorants are not used to provide a detection method. Many odorants can
also contaminate fuel cells.
THOUGHT-PROVOKING QUESTION
8.1
Are hydrogen fuel cells a viable energy option? Explain.
REFERENCES AND RECOMMENDED READING
NREL. (2009).
Ultracapacitors
. Washington, DC: National Renewable Energy Laboratory
(http://www.nrel.gov/vehiclesandfuels/energystorage/ultracapacitors.html?print).
