Advantages:

1. The hydrogen fuel cell produces water as the only waste products. No harmful gases are released to surroundings when it is used.

 2. Hydrogen is an abundant resource, if a cost effective method can be used to extract hydrogen from water.

Disadvantages:

1. There is currently no cost effective method of storing the hydrogen gas.

2. There is currently no cost effective method of extracting hydrogen from seawater.

3. The process to obtain hydrogen, either from electrolysis of water, or from cracking of hydrocarbons, produces waste gases and use up large amount of energy.