Wind power in Ontario: Quantifying the benefits of geographic diversity
Author:
Abstract. Integrating wind power into the Ontario electricity system requires managing its variability. Many studies and proponents of wind power claim that positioning wind farms in geographically diverse locations will mitigate variability and smooth wind power’s contribution to electricity generation. Our study analyzes the actual electricity production of wind farms in Ontario with capacities larger than 40 MW for 32 months (March 2006 to December 2008). Seasonal correlations between wind farm outputs are generated and graphed against the distances separating the wind farms. The effect on overall wind production variability of geographic diversity in the locations of wind output is then investigated. The average absolute hourly change in seasonal output is examined, as is change in standard deviation. Results confirm that correlations between wind farm outputs decay with distance. Distances of approximately 250 km are required to reduce the correlation coefficient between the hourly outputs of two wind farms to 0.5 – a representative limit for strongly synchronous outputs. To illustrate the smoothing potential of distance, the variability of output from a closely located group of wind farms was compared before and after adding the output of a farm located 364 km away from closest other farm. In this case, the change in standard deviation was only from 23.9% to 21.2% of the aggregate installed wind power capacity. This study’s results agree with European studies, but indicate that distance provides less smoothing of output in Ontario than has been found in some European countries. However, results disagree with findings of a study of Ontario’s wind potential conducted by General Electric.
(Draft version of paper presented at the Jan. 28, 2009, IESO Wind Power Standing Committee meeting, Ontario.)
