11 Laptop computers, a sewage treatment plant, and vending machines powered by fuel cells are also being tested and demonstrated. 12 Pros and Cons Fuel cells have several benefits. 13 Fuel cells can also maintain their high efficiencies when run at a fraction of their rated capacity, a significant advantage over gasoline engines. Because the efficiency of a set of fuel cells is determined by the performance of the individual cells, small fuel cell power plants are as efficient as large ones. Also, waste heat from stationary fuel cell systems can be used for space and water heating, further increasing efficiency of energy use.
Fuel cells are virtually emissions-free.
When fueled by pure hydrogen, heat and pure water vapor are the only by-products. In fact, Space Shuttle astronauts drink the water generated by on-board fuel cells. 14 Other emissions depend on the source of the hydrogen supply. Using methanol results in zero emission of nitrogen oxides and carbon monoxide and very small hydrocarbon emissions. Emissions increase going from hydrogen to methanol to gasoline, yet very low emissions would still be achieved using gasoline.