A financial benefit-cost analysis of different community solar approaches in the Northeastern US

Abstract

Community solar farms (CSF) have the potential to expand solar access and improve financial viability compared to traditional residential and commercial solar options. The Cook County Community Solar Project created and made publicly available 26 benefit-cost analysis spreadsheets and associated white papers for 15 case study CSF locations in Illinois with proposed panel leasing financial models. We update these spreadsheets to reflect current federal incentives, fix some key errors, and compare the net present value, annual cash flow, return on investment, and simple payback period for all 26 panel leasing financial models; apply the panel leasing model to a Maine-based location; develop and apply to Maine three additional financial models: lease-to-own, panel purchase with developer, and grassroots “true ownership”; and provide a comparative analysis of the effects of federal and state incentives on CSF panel leasing in Maine and Illinois. Illinois panel lease results for subscribers, owners, and hosts, respectively, include net present values ($2019 thousands) of -$127 to $27, $6 to $450, -$490 to $473; return on investment of −53% to 295%, 8% to 117%, −44% to 474%; and simple payback period (years) of 0 to 20, 3.6 to 20, 0 to 20, (with system owner internal rate of return set at 10%). Respective Maine results include: $5 to $9, $4 to $201, $193 to $209; 84% to 262%, 26% to 207%, 116% to 309%; 0 to 8, 1 to 14, 0 to 3. Holding all else equal, higher electricity prices, a lower labor rate, and a 1:1 net metering bill credit policy yield greater subscriber and host (anchor subscriber) benefits for Maine than Illinois. Although the panel purchase model yields the greatest net present value (NPV) for subscriber and host in the Maine analysis, it yields the lowest developer NPV and requires a large upfront cost to subscribers that may limit participation to those with higher income. Therefore, we recommend the lease-to-own model for the Maine case study site, as it provides positive substantial NPV for all three stakeholder types without large upfront costs for subscribers and with a path to ownership.