Fuel Cell
An electrochemical device that converts hydrogen and oxygen directly into electricity, water, and heat — the reverse of electrolysis. Fuel cells are 40-60% electrically efficient with no combustion emissions.
Why It Matters
Fuel cells are used in hydrogen vehicles (Toyota Mirai), forklifts (~70,000 in U.S. warehouses), backup power, and stationary generation. They're a key hydrogen end-use technology.
Related Topics
Related Terms
Green Hydrogen
Hydrogen produced by splitting water (electrolysis) using renewable electricity. The process produces zero direct greenhouse gas emissions. Currently costs $4-$8/kg vs. $1-$2/kg for conventional (gray) hydrogen.
Electrolysis
The process of using electricity to split water (H2O) into hydrogen (H2) and oxygen (O2). The main electrolyzer types are PEM (proton exchange membrane), alkaline, and solid oxide (SOEC).