Fuel Cells have been around for two centuries and have been in practical use for four decades. With the advance of technology and growing interest in developing alternate sources of energy, the fuel cell is about to come into its own.
Fuel Cells have been around for almost two hundred years and have been in practical use for decades. But there have always been used in niche applications, such as in the US space program. But with interest rising in alternative energy sources which avoid pollution and dependence on foreign sources of fuel, this may be about to change.
What is a Fuel Cell?
A fuel cell uses hydrogen and oxygen as fuel, combining the two to create water, heat, and electricity. A fuel cell is for all intents and purposes a battery that does not need recharging. As long as hydrogen and oxygen fuel are available, it can continue to supply heat and an electrical current indefinitely. A fuel cell contains an electrolyte (a conductor of charged particles) between an anode (negatively charged electrode) and a cathode (a positively charged electrode). Once triggered by a catalyst, the hydrogen atoms separates into protons and electrons, and the electrons are conducted through a wire, forming an electrical current. The protons move through the electrolyte, where they combine with oxygen and other electrons to produce heat and a water byproduct.
A catalyst is defined as a substance that modifies and increases the rate of a reaction without being consumed in the processes. Fuel cells which run at low temperatures require efficient catalysts. The majority of catalysts used in fuel cells are made primarily of platinum.
The History of Fuel Cells
The fuel cell was first developed in 1838 by William Robert Grove, a British scientist. Grove discovered that by arranging two platinum electrodes with one end of each immersed in a container of sulfuric acid and the other ends separately sealed in containers of oxygen and hydrogen, a constant current would flow between the electrodes. The sealed containers held water as well as the gases, and he noted that the water level rose in both tubes as the current flowed. By combining several sets of these electrodes in a series circuit, he created what he called a "gas battery"- the first fuel cell.
Fuel cells remained a laboratory curiosity, though, for over a century, until Francis Thomas Bacon began researching fuel cells in the late 1930. During the Second World War, Bacon developed fuel cells for use in British submarines. By the late 1950s a practical fuel cell that caught the attention of Pratt and Whitney. Pratt and Whitney bough the license for the technology and used it for powering American space craft, including Gemini, Apollo, and the space shuttle.
By the 1980s, fuel cells caught the attention of private companies as a possible new energy source. Every major automobile company has fuel cell powered cars in development. Other companies, such as Fuel Cell Inc., are developing fuel cells powerful enough to power office buildings or strip centers.
Advantages of Fuel Cells
Fuel Cells do not create pollution or toxic byproducts, as do fossil fuels or nuclear energy. Fuel Cells use the most commonly available substance on Earth, hydrogen, as part of its fuel. It emits heat, which can be tapped in certain applications such as space or water heating, and water as byproducts. Fuel Cells are also more energy efficient than gasoline or diesel engines. The lack of moving parts in Fuel Cells contributes to their low maintenance cost. Fuel Cells also run very quietly compared to other sources of energy.
Problems with Fuel Cells
Fuel Cells are currently very expensive, costing about 4500 dollars per kilowatt, as opposed to 800 to 1000 dollars per kilowatt for a diesel engine. There are also problems with using hydrogen as fuel. Hydrogen is one of the most volatile substances on Earth, prone to combustion. It is also more difficult to store in a fuel tank than, say, gasoline. Also the hydrogen has to be very pure or else it would begin to damage the catalyst. Hydrogen has to be extracted from sources like water or natural gas, generating more energy costs. Finally, the most common material used as a catalyst, platinum, is rare enough on Earth that if every car on the planet were converted from internal combustion engines to fuel cells, there would not be enough platinum to build the fuel cells.
Solutions
Research and development is ongoing to decrease the cost and increase the efficiency of fuel cells. Hydrogen can be extracted from water or natural gas using nonpolluting energy sources such as solar. Fuel processors can be added to fuel cells that would extract hydrogen from natural gas—for example. This would allow cars to be powered by natural gas. One problem is that while even this technology produces less pollution than standard gasoline and diesel engines, it still produces significant amounts of carbon dioxide, which is a cause of global warming.
The shortage of platinum as a catalyst can be addressed in one of two ways. Other materials can be found to serve as a catalyst. Research is ongoing in this area. The second method is to find other sources of platinum and related metals. Aerospace engineer Dennis Wingo has suggested that there are sources of these materials on the Moon or Earth approaching asteroids that can be mined economically, if the decision is made to convert to a hydrogen economy.
A Hydrogen Economy
What would a hydrogen economy look like? Automobiles and other vehicles would be powered by fuel cells, rather than internal combustion engines, resulting in a drastic reduction of pollution and a massive decrease in dependence on foreign sources of fuel. The first fuel cells that would power vehicles would probably, because of their large size and expense, be used to power buses, large trucks, and similar vehicles.
Larger fuel cells could help power homes, office buildings and shopping malls, supplementing larger, more centralized sources of electricity. This combination would tend to alleviate the prospect of black outs, brown outs, and other power fluctuations. This in turn decreases the incidents of data losses on computers and the shut down of industrial assembly lines.
There are even tinier fuel cells that could, one day, replace the dry cell battery. They can run lap top computers, cell phones, or even CD players.
Hydrogen would be extracted by power plants, running on a number of technologies such as solar, space based solar, nuclear, or even fusion when that technology is developed.
When will fuel cells take their rightful place among other energy sources in the 21st century? While the benefits of fuel cells are undeniable, many hurdles stand in the way of their ascendance however. The high expense when compared to other energy sources, the need for time to warm-up and pressure for efficient operation, the lifetime of the cell as a whole, and the potential for the poisoning of the sensitive catalysts are all issues standing in the way of integration of fuel cell technology into the energy systems of the nation. Technological advances are addressing these problems across the board. It could be that by the second decade of this century, according to some experts, energy derived from the burning of coal or oil will start to become obsolete, revolutionizing the world’s energy infrastructure.
External Links:
Fuel Cell 2000 - A Noprofit Source for Fuel Cell Information