The Illinois Third District Appellate Court recently issued a landmark decision in Equity Solar Illinois v. County of Grundy, 2026 IL App (3d) 250289, marking the state’s first appellate ruling to clarify the limits of local government authority over renewable energy siting. The court affirmed that under the state’s 2023 "Solar Amendments" to the Counties Code, local counties are legally required to issue special use permits to commercial solar energy facilities that meet the state’s uniform standards, effectively stripping counties of the discretionary power they once held to deny such projects based on subjective local preferences.
The dispute began in 2023 when Equity Solar Illinois submitted applications to build two commercial solar farms on agricultural land in unincorporated Grundy County. Despite the applications complying with the rigorous technical and safety requirements established by the state legislature, the Grundy County Board followed the recommendations of its Zoning Board of Appeals and Land Use Committee to deny the permits. The county’s reasoning rested on traditional zoning considerations, including claims that the projects were incompatible with the surrounding area, potentially harmful to future airport expansion in the nearby City of Morris, and not in the best interest of the county's future commercial development.
Equity Solar challenged this denial through a mandamus action, arguing that the 2023 Solar Amendments created a nondiscretionary duty for the county. The developers contended that if a project meets the specific setbacks, height restrictions, and environmental protections outlined in Section 5-12020 of the Counties Code, the county "shall" approve the request. The circuit court agreed, issuing a writ of mandamus that ordered Grundy County to green-light the projects. The county appealed, seeking to retain its historical authority to balance solar development against other local planning priorities.
In its ruling, the Appellate Court emphasized that the Solar Amendments were passed against a clear public policy backdrop: Illinois intends to transition to 100% clean energy by 2050. The court found that the state legislature intentionally moved away from a "home rule" or local-control approach for large-scale solar and wind projects to prevent a patchwork of inconsistent local regulations from stalling the state’s green energy goals. By establishing a comprehensive state-wide framework, the legislature limited a county's role to verifying compliance with those specific standards rather than exercising broad "special use" discretion.
The court's decision clarifies that while counties can still hold public hearings and regulate certain aspects like vegetative screening or drainage, they cannot use those proceedings to veto a project that otherwise satisfies state criteria.
This decision is now a binding rule of law for all lower courts within the Third District Appellate Court jurisdiction.