Simplified Approach to Assess the Capacity Credit of Wind Electric Conversion Systems

Abstract

Wind electric conversion has become one of the most promising technologies to address the various energy issues facing the United States. National initiatives such as "20% electricity from wind by 2030" and grand plans to replace some of the gas-fired electric generation by wind so that the saved gas can be used in compressed form to power automobiles leading to a decrease in importation of petroleum are manifestations of the progress made just in the past decade. Among the many issues for consideration as the penetration of wind generated electric power into conventional power systems increases, quantification of "energy credit" and "capacity credit" ranks high because of its direct economic impact. This study considers the issue of capacity credit and its assessment. Capacity credit can be assessed by detailed simulation using iterative or non-iterative methods. Considerable work has been done in these areas. However, these techniques are cumbersome and require considerable amount of data and information. The simplified approach presented in this study employs an effective forced outage rate for a wind generator and uses the classic loss of load probability calculations to estimate/assess the capacity credit. The result is a good estimate for capacity credit and it can be followed by detailed calculations as needed. Results of sensitivity analyses are presented to study the impact of penetration levels, amount of spinning reserve, wind parameters and wind turbine output characteristics.