Image: NEC
Opposites attract
Fuel cells use hydrogen and oxygen to produce electricity and in the process create by-products of water and heat. They operate much like batteries but with an important difference -- they never go dead or need to be recharged. The basic set-up consists of two electrodes sandwiched around an electrolyte membrane. Oxygen is placed at the cathode, the positively charged electrode. Hydrogen fuel is placed at the anode, the negatively charged electrode.
Each electrode is made of a catalyst such as platinum, which causes the oxygen and hydrogen to ionize. When the hydrogen atoms touch the anode, they break down into positive protons and negative electrons. Both are naturally attracted to the cathode on the opposite side of the membrane between the two electrodes.
The membrane between the anode and cathode is created with layers of electrochemical material and only positively charged molecules can get through. The negative electrons take a different route around the membrane and are shunted through a circuit that generates electricity. These hydrogen atoms eventually reach the cathode and bind with the waiting oxygen ions. The binding of the protons creates two different waste products -- heat and water vapour. Both of these can also be harnessed into electrical energy as well.
Since there is no combustion, there are no greenhouse gas emissions or noise pollution. Fuel cells are also two to three times more efficient than burning fossil fuel like oil or coal. The voltage from a single cell is about 0.7 volts, just about enough for a light bulb, but when the cells are stacked together, the operating voltage increases by 0.7 multiplied by the number of cells, making them an attractive alternative to anything that runs on electricity or on oil.
Fuel cell applications
There are many different types of fuel cells that can be used in a variety of applications. They're a natural fit for vehicles to replace our inefficient and polluting internal combustion engines. Fuel cells for cars have come a long way since the first prototype with its short range and tedious recharging. They are also immensely suitable for speciality vehicles such as forklifts.
But they are also excellent for stationary applications like CHP (combined heat and power) or HVAC (heating, ventilation and air conditioning) because they never run out of energy nor do they have a grid system that can blow up causing a blackout. Both the Durst building in New York and The First National Bank of Omaha chose fuel cells for this very reason. During the 2003 New York blackout the fuel cell powered Central Park Police Station was the only place with electricity.
Fuel cells are also proving to be a cost-effective backup for telecommunications since they are reliable, rugged and durable. They can be left alone for long periods of time in remote places, such as the top of a mountain.
Laptops, cell phones and other portable electronics are prime candidates for fuel cells. Micro fuel cells last longer than conventional batteries, allowing a typical laptop to operate unplugged for 10 hours or more. Battery rechargers and AC adapters also become redundant.
If you're interested in learning more about fuel cells and their many applications visit Fuel Cells 2000. This is educational website was developed by the non-profit organization Breakthrough Technologies Institute (BTI) to help explain and promote this new technology. Their interactive map can also show you distributors in the United States, Canada and Europe.
Few obstacles left
Fuel cells hold a lot of promise but there are a few major issues that still need to be sorted out. The most pressing problem is the expense of the platinum used in the electrodes and membrane. Researchers must either decrease the amount of platinum needed to act as a catalyst or find an alternative. The membranes also remain sensitive to temperature but researchers have made great molten carbonate and solid oxide fuel cells that can operate at extremely high or low temperatures. The final obstacle is to create a production line and delivery system so the consumer can have access.
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