In fuel cells hydrogen, in the molecules of which chemical energy is stored, is burned and energy heat and water is produced.
Fuel cells do not store energy inside them as it happens to batteries. The fuel, that means the hydrogen is stored in an external tank, waiting to be used (as petrol is store in the car's tank or the wood is stored in the cellar waiting to be used in the fireplace). Fuel cells generate electricity and heat for as long as hydrogen is provided. The fuel cells are compact, efficient, and does not pollute the area where the hydrogen is burned.
Though energy is required in order to produce hydrogen (extract it from water)
In the future fuel cells will be installed in cars, or for producing electricity and heat.
Research in fuel cells is an ongoing research.
The first fuel cell was built in 1839 by William Grove.