What is a fuel cell?
A fuel cell is a highly efficient and ultra clean power generation system that generates electricity and heat from the electrochemical reaction between hydrogen and oxygen. A fuel cell generates electricity directly, without undergoing an energy conversion process through fuel combustion, such as with a conventional power plant, making it highly efficient, eco-friendly, and readily available for distributed generation. A fuel cell uses hydrogen or hydrogen-rich fuel such as natural gas, and oxygen to create electricity.
Fuel cells can be used to provide propulsion or auxiliary power for transportation applications, including cars, trucks, buses, trains, ships, and submarines. They have been used to provide auxiliary power on spacecraft for decades.
Fuel cells are a versatile technology, as each fuel cell type has its own operational characteristics. This has enabled a broader range of applications than any other currently available power source, from large power plants, vehicles and residential power to mobile chargers and toys.
How Fuel Cells operate
A fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity, with water and heat as its by-product. In its simplest form, a single fuel cell consists of two electrodes – an anode and a cathode – with an electrolyte between them. At the anode, hydrogen reacts with a catalyst, creating a positively charged ion and a negatively charged electron. The proton then passes through the electrolyte, while the electron travels through a circuit, creating a current. At the cathode, oxygen reacts with the ion and electron, forming water and useful heat.
When cells are stacked in series the output increases, ranging anywhere from several watts to multiple megawatts. Since fuel cells rely on an electrochemical process and not combustion, emissions from fuel cells are significantly lower than emissions from even the cleanest fuel combustion processes. Fuel cells are also quiet, durable, and highly efficient.
Images and Case Studies
Central Park Police Station
Adobe’s San Francisco fuel cell installation. Courtesy Bloom Energy