Fuel cells are electrochemical cells that generate electrical energy from fuel via an electrochemical reaction. They are similar to electrochemical cells, consisting of a cathode, an anode, and an electrolyte. The electrolyte enables the movement of the protons. Fuel cells are unique in terms of the variety of their potential applications; they can use a wide range of fuels and feedstocks and can provide power for systems as large as a utility power station and as small as a laptop computer. Some types of fuel cells include:

• Polymer Electrolyte Membrane (PEM) Fuel Cell: These cells are also known as proton exchange membrane fuel cells (or PEMFCs). They operate in a temperature range between 50oC to 100oC and use a polymer electrolyte that can conduct protons. They are highly efficient and produce heat and water along with electricity.

• Solid Oxide Fuel Cell: These cells involve the use of a solid oxide or a ceramic electrolyte (such as yttria-stabilized zirconia). They are highly efficient and have a relatively low cost (theoretical efficiency can even approach 85%). They have a relatively high operating temperature.

Fuel cells have several benefits over conventional combustion-based technologies currently used in many power plants and vehicles. Fuel cells can operate at higher efficiencies than combustion engines and can convert the chemical energy in the fuel directly to electrical energy with efficiencies capable of exceeding 60%. Fuel cells have lower or zero emissions compared to combustion engines.

Fuel cells have a wide range of applications, providing power for applications across multiple sectors, including transportation, industrial/commercial/residential buildings, and long-term energy storage for the grid in reversible systems.