Hydrogen fuel cells are devices that convert chemical energy from hydrogen into electricity through a chemical reaction with oxygen. This process produces only water and heat as byproducts, making it a clean energy source. Fuel cells can power various applications, from vehicles to stationary power systems. In a hydrogen fuel cell, hydrogen gas is fed into the anode side, while oxygen (often from air) enters the cathode side. The reaction generates electricity, which can be used immediately or stored for later use. This technology is part of the broader movement towards sustainable energy solutions, alongside other methods like solar and wind power.