Challenges in Sustainability

Abstract: Rooftop solar photovoltaics will play a role in decarbonizing electricity generation and meeting global climate goals. Policymakers can benefit from understanding how their policy choices impact rooftop solar PV adoption. We conduct a case study of Regina, Saskatchewan to determine the extent to which solar policy changes in that Canadian province have impacted the relative desirability of rooftop solar PV. We assess financial returns that can be achieved in Regina under three policy scenarios: net metering, net billing, and net billing with a capital incentive. We use GIS analysis to identify suitable roofs in Regina and assess any shading that may occur. We calculate hourly capacity factors for these roofs using solar irradiation data, temperature data, and shading factors. We match the simulated solar output results with hourly load data to simulate over 4 million potential roof-load combinations and calculate NPV and net monthly return for each combination. We conduct a telephone survey of 451 Regina residents to assess willingness to install solar at different levels of financial return and compare these results to our solar simulations. Our results indicate that a move from net metering to net billing reduced financial returns from rooftop solar and lowered solar potential from 129 Gigawatt-hours (GWh) per year to 99 GWh/yr in Regina. The introduction of a capital incentive grant by the federal government has helped increase solar potential upwards to 120 GWh/yr. The capital incentive grant may also help overcome high discount rates by providing a larger upfront benefit to households that install solar.