Simplified methods for renewable generation capacity credit calculation: A critical review

Capacity credits are widely used to quantify the ability of different generating technologies to support demand. Most practical capacity credit calculations are based on detailed risk modelling, however a wide range of simplified approaches are also in use. This paper presents a critical review of these simplified approaches, ranging from annual peak calculations and probabilistic representations of wind, to closed-form expressions derived for small installed wind capacities. The principal themes are that simplified methods must retain the key features of the problem at hand, and that to be of interest simplified methods must either bring substantial computational advantages, or provide additional insight beyond that from a more detailed risk calculation.