Unlike traditional combustion technologies that burn fuel, fuel cells undergo a chemical process to convert hydrogen-rich fuel into electricity. Fuel cells do not need to be periodically recharged like batteries, but instead continue to produce electricity as long as a fuel source is provided.
A fuel cell is composed of an anode, a cathode, and an electrolyte membrane. A fuel cell works by passing hydrogen through the anode of a fuel cell and oxygen through the cathode. At the anode site, the hydrogen molecules are split into electrons and protons. The protons pass through the electrolyte membrane, while the electrons are forced through a circuit, generating an electric current and excess heat. At the cathode, the protons, electrons, and oxygen combine to produce water molecules.
Due to their high efficiency, fuel cells are very clean, with their only by-products being electricity, excess heat, and water. In addition, as fuel cells do not have any moving parts, they operate near-silently.
Fuel cells are also scalable. This means that individual fuel cells can be compiled on one another to form stacks, in turn, these stacks can be combined into larger systems. Fuel cell systems vary greatly in size and power, from portable systems for smartphone battery recharging, to combustion engine replacements for electric vehicles, to large-scale, multi-megawatt installations providing electricity directly to the utility grid.