Selected properties of wind capacity contributions applications of the constant z-statistic method

The relatively complex relationship between power demand and wind generation patterns complicates estimating and communicating wind generation capacity contribution. Standard utility methods such as establishing minimum reserve margins are generally not adequate. Load carrying capability of wind projects can be assessed with probabilistic metrics using stochastic power system models. However, stochastic methods tend to be relatively expensive and cumbersome for assessing multiple projects. The constant z-statistic method provides a simple analytical estimate for incremental resource additions that can be helpful in applications with multiple wind projects where correlations among project output is also a consideration. This paper reviews the constant z-statistic method as applied to wind projects, and examines properties of wind capacity through examples.