Capacity is the amount of electricity a generator can produce when it's running at full blast. This maximum amount of power is typically measured in megawatts and helps utilities project just how big of an electricity load a generator can handle. Wind energy is harnessed directly from the flow of air through the use of onshore and offshore wind energy technologies.Onshore wind power refers to turbines that are located on land and use wind to generate electricity. Offshore wind power is the generation of electricity through wind farms in bodies of water, usually at sea.