Nameplate capacity

[7][8] For dispatchable power, this capacity depends on the internal technical capability of the plant to maintain output for a reasonable amount of time (for example, a day), neither momentarily nor permanently, and without considering external events such as lack of fuel or internal events such as maintenance.

[9][10] For non-dispatchable power, particularly renewable energy, nameplate capacity refers to generation under ideal conditions.

Output is generally limited by weather conditions, hydroelectric dam water levels, tidal variations and other outside forces.

Equipment failures and maintenance usually contribute less to capacity factor reduction than the innate variation of the power source.

In photovoltaics, capacity is rated under Standard Test Conditions usually expressed as watt-peak (Wp).