ABSTRACT
Energy in wind and incoming solar radiation has been observed to be complementary over time. That is, as one of these resources slackens, the other tends to increase. Considering the intermittency of wind and solar radiation, complementarity provides the potential to better exploit the two resources in combination. How well a hybrid system using both resources can improve the reliability of energy generation is partially a function of their complementarity. This study developed an approach to calculate the Complementarity Index of Wind and Solar Radiation (CIWS). Geographic analyses including principal component analysis and geographically weighted regression modeling were applied to investigate the impacts of diverse geographic factors on complementarity. Oklahoma was used as the case study area because of the availability of quality-controlled five-minute data from 127 Mesonet sites. The results indicate average CIWS (unitless) is 10.99, about 46 percent of the theoretical maximum value of 24; the standard deviation is 1.5. Approximately 57 percent of the sites have above-average CIWS values. Also, complementarity is spatially skewed, with the highest CIWS values falling in the east, where both wind and solar energy are less abundant. Geographic analysis shows three groups of geographic factors including moisture, temperature, and landscape explain 86.6 percent of variations in complementarity. Key Words: complementarity, geographically weighted regression, Oklahoma, solar energy, wind energy.
