About Fuel Cells
Fuel cells operate on the same principle as batteries. Whereas batteries consume their reactants and must be recharged, fuel cells operate as long as there is fuel. They use the hydrogen and oxygen extracted from the fuel and the atmosphere to create electricity, heat and water vapor. The key to the reaction is the specialized materials called electrolytes in which ionized atoms are soluble, but electrons are not, which creates the electricity.
William Grove produced the first fuel cell in 1839. Fuel cells were used to power all onboard electronics in the US Apollo rocket program in the 1960’s, clocking over 10,000 hours without incident. Since then, various fuel cell chemistries have been developed and have resulted in products that each suitable for a range of applications. The table below lists various fuel cell approaches:
Fuel cells are more efficient than traditional engines because there are no energy losses to mechanics. Most power generators are 25 to 35 percent electrically efficient compared to a fuel cell that is typically 40 to 60 percent efficient. Fuel cells’ chemical reaction converts directly to energy:
Reaction » mechanical motion » electricity
Reaction » electricity
The typical fuel cell involves the flow of hydrogen and air on either side of the specialized material. With the help of a catalyst, the hydrogen is ionized and migrates through the material to combine with the oxygen. The electrons that the hydrogen gives up are collected in an external circuit --and electricity is made.
In a tubular solid oxide fuel cell, the hydrogen flows through a tube that serves as the anode. In this case oxygen molecules from the air are ionized and produce electrons to generate electricity. The ions pass through a solid zirconia electrolyte that is more rugged than traditional molten salts or polymer membranes. In fact, this electrolyte has a similar construction as oxygen sensors that have performed reliably in automobiles for many years.
Not all fuel cells require hydrogen. Solid oxide fuel cells have very stable ceramics that operate at high temperature and can operate on traditional hydrocarbons like natural gas, methane, biofuels and liquid fuels. While this still produces carbon dioxide (a greenhouse gas), it produces significantly less carbon dioxide (CO2) in inverse proportion to the efficiency of our fuel cells vs. traditional generators. Typically our fuel cell will produce one half the CO2 that a small combustion engine would. Most importantly, since fuel cells produce electricity through a chemical process, there are virtually no nitrogen oxide (NOx) and sulfur oxide (SOx) emissions and the added efficiency means less fuel is needed to produce power.