Capacity credit of wind power in the Netherlands

Abstract

The Dutch Government has stated that by the year 2000 a total amount of 1000 MW wind power should be installed in the Netherlands. The penetration of wind power into the electricity supply system poses questions about the costs and benefits of wind power. One of the parameters affecting the benefits is the amount of conventional capacity that can be saved by wind power, the so-called ‘capacity credit’. In this study the capacity credit of wind power in the Netherlands is analysed. The capacity credit is calculated using a probabilistic method which evaluates the loss of load expectation (LOLE) of the total electricity generating system. In these evaluations the available wind power is treated as ‘negative load’. The capacity credit is evaluated with respect to the Dutch electricity generating system and the electricity demand that is projected for the year 2000 by the Dutch utilities. Special attention is given to modelling the hourly wind power production. The model incorporates detailed siting information, wind speed data for several meteorological stations and the power curves of five different types of wind turbines. The average amount of electricity produced by wind power can be expressed by the capacity factor. For the set of assumptions and for the meteorological conditions for the years investigated the capacity factor has a value of 22%. The mean value of the capacity credit of 1000 MW of wind power is calculated to be 184 MW or 18.4% of the installed wind turbine capacity. This value depends on several parameters, the influence of which is investigated. It is shown that there is a strong correlation between the capacity factor of wind power and the related capacity credit. The capacity credit is also influenced by the penetration level of wind power. The capacity credit, expressed as a percentage of installed wind turbine capacity, decreases with increasing wind turbine capacity. When 100 MW of wind turbine capacity has been installed the capacity credit is 28%. For 2000 MW of wind power this value is 13.6%. Furthermore, it is shown that geographical dispersal of the wind turbines over the Netherlands has a positive effect on the capacity credit. The capacity credit of 1000 MW dispersed over the Netherlands is 34 MW higher than the capacity credit of 1000 MW imaginarily installed at one location.