The Economics of Residential Solar Panels: A Comparison of Energy Charges for Different Load Profiles, Rate Plans, and Panel Orientations

This paper examines the effect of different residential electrical load profiles (electrical energy consumption patterns within a day) on energy charges for customers with solar panels under different Southern California Edison time-of-use (TOU) rate plans. We identify the TOU plan which would be the most cost effective for solar customers with each load profile. The impact of the orientation of the solar panel array (whether it faces south or west or east) and shading patterns on electricity charges are examined. We also determine the ideal usage offset (the percentage of electricity consumption provided by the solar array) for the various scenarios presented in this paper. We perform these analyses using actual data for the average sized residential customer of Southern California Edison. While the data we examine are based on solar panel production estimates for southern California, the issues we address, and the methods we use, are applicable to virtually any locality. And our analysis reveals how myriad factors impact the economics of residential solar panel systems regardless of location.