In Ontario (Canada), the integration of renewable power is a priority policy goal. Since 2004, the circumstances under which the integration of renewable power is evaluated have changed due to successive changes in price as well as concerns that its over-production may add to grid congestion. This research investigates the value of increasing complementarity (both proximate and geographically dispersed) of wind and solar resources as a means by which electricity planners and researchers might advance electricity sustainability in Ontario. More specifically, this paper asks the following questions: 1) Does the combination of solar and wind resources in selected locations in Ontario serve to 'smooth out' power production, i.e., decrease instances of both high and low values, as compared to either resource producing individually? 2) Can this 'smoothness' be further improved by dispersing these resources geographically amongst locations? and 3) Does increasing the number of locations with solar and wind resources further 'smooth out' power production? Three years (2003-2005) of synchronous, hourly measurements of solar irradiance and wind speeds from Environment Canada's Canadian Weather Energy and Engineering Data Sets (CWEEDS) are used to derive dimensionless indices for four locations in Ontario (Toronto, Wiarton, Sault Ste. Marie and Ottawa). These indices are used to develop three transparent and accessible methods of analysis: (1) graphical representation; (2) percentile ranking; and (3) using a theoretical maximum as a proxy for capacity. The article concludes that the combination of solar and wind within locations and amongst two locations improves 'smoothness' in power production, as compared to when each resource is produced on its own; moreover, it is further improved once more than two resources and two locations are combined. However, there is neither further benefit, nor drawback, associated with the geographic dispersion of complementarity between solar in one location and wind in another, when compared to both resources in one location. (c) 2010 Elsevier Ltd. All rights reserved.