Modelling the Impact of Wind Power Fluctuations on the Load following Capability of an Isolated Thermal Power System

Abstract

Wind power is a clean and commercially competitive renewable energy technology that affords many utilities the opportunity to diversify and reduce their dependence on fossil fuels. However, the wind is also an intermittent energy source. Hence, many small and isolated utilities are concerned that, as the number and capacity of wind power plants increases, the resulting fluctuations in wind power output will impose excessive load following duty on their conventional units, leading to grid frequency control problems. This paper investigates the potential impact of wind energy development on the load following capability of a representative medium-sized, (2000 MW) thermal power system. Recorded system demand and wind power production data from the Northern Ireland system are statistically analysed, and the impact of expanded wind farm operation on net wind power and system demand fluctuations modelled and predicted for various time-scales of interest. The results demonstrate that the magnitudes of power output fluctuations from well-dispersed wind farms are small compared to system demand variations. Consequently, wind power expansion will not impose significant additional load following duty on the power system. Statistical analysis of net system demand and scaled wind farm time series data empirically verifies the validity of these findings.