Hydrogen Fuel Cells

As time goes on, technological advances require more efficient sources of power. At the forefront of research for these power sources are hydrogen fuel cells. This power source takes in the most abundant element in the universe, Hydrogen, and yields immense power without combustion or pollution. The three aspects of this scientific breakthrough are the fuel cells, hydrogen production, and hydrogen storage.

Fuel cells are the devices with which Hydrogen is made into electricity. These use a technology much similar to that of something we are very familiar with: the battery. According to the National Renewable Energy Laboratory, or NREL, like the battery, fuel cells use chemical reactions to generate electricity rather than combustion. Unlike the battery, however, the "ingredients" for this reaction are not stored within the cell, rather they are taken in from outside, making their potential so much more efficient and giving them a longer time span to power whatever happens to be connected to them. According to the United States Department of Energy, within the fuel cell, two reactions occur. One is an oxidation half-reaction at an anode and the other is a reduction half-reaction at a cathode. Under normal conditions, this process would be very slow. The manufacturers speed this up by adding a catalyst to one side of the anode and cathode each. The most common of these catalysts consists of platinum powder very thinly coated onto a carbon paper or cloth. The reactions that occur give off very large amounts of energy and do so without releasing pollutants. The only byproduct is water vapor.

Hydrogen is in fact the most abundant element in the universe, although it is usually found in compounds. Since the fuel cells require pure hydrogen, it must be separated from these compounds in a manner in which it creates renewable energy. According to NREL, the four most promising of ways to do this are the following.

Thermochemical hydrogen is produced by heating biomass with limited or no oxygen, either gasifying it to what is called syngas, a mixture of hydrogen and carbon monoxide, or liquefying it into pryolysis oil. Syngas then goes through what is referred to as a water-gas-shift reaction to increase the amount of hydrogen. Pryolysis oil uses a steam reformation technique in conjunction with the water-gas shift reaction.

Electrolytic Hydrogen is formed by a process completely opposite of that of the fuel cell, taking water and breaking it apart into hydrogen and oxygen with what is called an electrolyzer. An electrolyzer takes water molecules and applies electrical current to water, separating the hydrogen atoms from oxygen atoms. This requires an inexpensive source of electricity, the leading proposal being wind energy. Wind energy benefits the most because for use with an electronic grid, the electricity of wind energy must convert from direct current to alternating current and the electrolyzer requires direct current.

To form photoelectrochemical (PEC) hydrogen, one must "replace one electrode of an electrolyzer with photovoltaic (PV) semiconductor material to generate the electricity needed for the water-splitting reaction" (Hydro. Prod.). Photovoltaic semiconductor material is something that converts sunlight to electricity. NREL continues to say "the efficiency loss of separate steps is done away with, as is the cost of the other components of a solar cell. PEC is elegantly simple, but finding PV materials both strong enough to drive the water split and stable in a liquid system presents great challenges for researchers" (Hydro. Prod.).

The last technique scientists are researching is forming of hydrogen by means of nature. Some algae and bacteria use photosynthesis to make hydrogen instead of the usual sugar and oxygen. Challenges with this include the fact that the enzyme in the algae that produces hydrogen is hindered by oxygen,