Fuel cell electric vehicles (FCEVs) are quickly becoming a commercially viable sustainable transportation option for Americans. Unlike gasoline-powered cars, these cutting-edge vehicles are fueled by hydrogen and emit only water. The latest and greatest FCEVs are on display this week at the Washington Auto Show.
Even though FCEVs are some of the most advanced vehicles on the road today, they use some of the simplest technology in their propulsion systems. Polymer exchange membranes (PEMs) are the most common fuel cells used in FCEVs and consist of three main parts: positively charged cathodes, negatively charged anodes, and membranes in between the anodes and cathodes.
When you step on the "gas" pedal, hydrogen that’s stored in a tank onboard the FCEV flows into the anode of the fuel cell. When the hydrogen reacts with the anode catalyst, it loses electrons and is converted into protons. These protons then pass through the fuel cell membrane and combine with oxygen, which is provided from outside air to the cathode. The membrane plays a unique role because it allows only protons to pass through it, not electrons (if it did, you would just have an electrical short). Instead, the electrons flow through an external circuit to power the FCEV and then recombine with the oxygen and protons at the anode to produce water. So the only emission from the tailpipe is water- no carbon emissions or other pollutants like nitrogen oxides, sulfur oxides, soot or particulates. Since a single fuel cell is flat, they can be easily stacked and combined together to produce higher voltages and greater amounts of electricity. Check out the diagram below to see how the basic process works.
Not only do FCEVs produce far fewer harmful emissions than gasoline powered vehicles, they can also help reduce the nation’s dependency on foreign oil. In addition, FCEVs are quiet since there is no combustion or mechanical gears. FCEVs can be driven up to 300 miles on one tank of hydrogen and refueling takes less than five minutes.