the unitless ratio of a generation source's actual electrical energy output over a given period of time to the maximum possible electrical energy output over that same period. Capacity factor = Annual MWh / (365 x 24 x nameplate MW).
Enables comparison of energy generation sources regardless of fuel type
RE sources have low capacity factors
It's important to understand the impact a low capacity factor has on our need for 24 x 7 x 365 energy.