A fuel cell is an electrochemical energy converter. It converts the chemical energy of fuel (H2) directly into electricity. A fuel cell is like a battery but with constant fuel and oxidant supply (Fig. 7.12).
Fuel cells are preferred for the following reasons (Barbir 2005):
1. Promise of high efficiency
2. Promise of low or zero emissions
3. Run on hydrogen/fuel may be produced from indigenous sources/issue of national security
4. Simple/promise of low cost
5. No moving parts/promise of long life