Fuel cells, like batteries, convert chemical reactions into electricity but differ in the way they consume fuel. Sir William Grove's 1838 design paved the way for modern fuel cells, including the Bacon fuel cell used by NASA. Fuel cells come in various types such as alkaline, solid acid, phosphoric acid, molten carbonate, and solid oxide, each with specific fuel sources and byproducts. The use of fuel cells in stationary power grids is favored due to their lack of moving parts, offering an efficient power generation alternative. In space exploration, fuel cells have a long-standing history, with NASA utilizing different cell types over the years. While fuel cell cars face challenges in hydrogen delivery and infrastructure, buses and a few trains have successfully incorporated fuel cells for cleaner energy. Despite obstacles, fuel cells continue to be a promising technology for sustainable energy solutions.