Environmental Engineering Reference
In-Depth Information
Water is split into oxygen and hydrogen using electricity in a process called electrolysis.
Hydrogen can be extracted from hydrocarbons (mainly from natural gas) with extreme heat and pres-
sure.
B. Discuss two positive aspects of hydrogen as an energy source. (2 points maximum)
• 1 point: Hydrogen can be produced domestically, reducing dependence on foreign energy supplies.
• 1 point: The only emissions from hydrogen combustion are water and heat.
• 1 point: Hydrogen has three times the energy per mass of natural gas.
• 1 point: Hydrogen is the most abundant element in the universe, so it will not be depleted.
• 1 point: Unlike batteries, fuel cells do not need to be recharged by the addition of energy from anoth-
er source.
• 1 point: When compressed, hydrogen is not more dangerous than gasoline.
C. Discuss three reasons why opponents to hydrogen energy do not see it as a viable alternative to fossil
fuels. (3 points maximum)
• 1 point: Hydrogen needs to be isolated prior to use.
• 1 point: Currently, most hydrogen is produced from hydrocarbons in natural gas, a fossil fuel. This
does not help to reduce dependency on fossil fuels, and the process also releases carbon dioxide into
the atmosphere. This means that the hydrogen economy is dependent upon the price and availability
of natural gas.
• 1 point: Because it has low density, the storage of hydrogen is a challenge. It needs to be compressed
into a denser form for storage and transport.
• 1 point: Hydrogen can make metals brittle, weakening their structure. This creates challenges for
storage, transport, and use.
• 1 point: The process of isolating hydrogen for use may require large energy inputs, which could ne-
cessitate greenhouse gas emissions.
• 1 point: Currently, little infrastructure exists for the transport, storage, and retrieval of hydrogen.
D. In what ways has hydrogen fuel already been made available to consumers? (1 point maximum)
• 1 point: Currently, vehicles powered by hydrogen fuel cells—including cars, buses, and boats—are
available for purchase.
E. Discuss two reasons why alternative energy is currently an essential component of the world's energy
supply and may become more so in the future. (2 points maximum)
• 1 point: It reduces dependency on foreign energy supplies.
• 1 point: It provides a sustainable and renewable energy supply that will exist indefinitely.
• 1 point: It reduces harmful greenhouse gas emissions that contribute to climate change.
• 1 point: It reduces the environmental impact of drilling, mining, and other destructive processes as-
sociated with the extraction and refinement of fossil fuels.
• 1 point: It reduces or eliminates emissions harmful to human health, wildlife, and ecosystems.
