A Direct Method to Calculate Capacity Value of Variable Energy Resources

Abstract

This paper proposes a direct method to calculate the capacity value of variable energy resources (VERs) in generation adequacy planning studies. The capacity value is used to measure the contribution of VERs such as wind power to the adequacy of generation systems. Iterative methods are traditionally used to calculate the capacity value of VERs. However, iterative methods are computationally demanding even for power system planning studies. The proposed method is based on augmenting the cumulative distribution function (CDF) of the generation reserve margin (prior to adding VERs) to include the output power of VERs. From the augmented CDF of the generation reserve margin, the capacity value is analytically determined without performing iterations, thereby reducing the computational burden associated with calculating the capacity value of VERs. The proposed approach considers the correlation between the output of VERs and system load, output variability, and forced outages of VERs in the evaluation process. Further, using the proposed method, the optimal penetration level of VERs in terms of their capacity values is determined with greater ease than with iterative methods. The proposed method is demonstrated on the IEEE Reliability Test System (IEEE RTS) and used to calculate the capacity value of wind power.