Illinois Supreme Court Sets Stage to Resolve Solar Siting Split

The court’s acceptance of the Petition for Leave to Appeal signals that it will likely resolve the growing conflict among Illinois appellate courts concerning the scope of local discretion under the state’s solar siting law.

Background

As we previously detailed, Illinois’ Fourth District Appellate Court held in Tate Road Solar that counties retain discretion when reviewing solar siting applications and that courts cannot compel permit approval through mandamus, even where a project satisfies statewide standards established under Section 5-12020 of the Counties Code. The Tate Road Solar court also held that counties could consider factors and impose requirements outside of the statewide standards. 

That ruling sharply contrasted with the Third District Appellate Court’s decision in Equity Solar Illinois v. County of Grundy, which concluded that counties are required to approve qualifying projects that meet statutory standards and that mandamus is available when a county improperly refuses to issue a permit. The Equity Solar court held that counties are unable to impose requirements for solar siting beyond those permitted by Section 5-12020. 

The conflicting decisions created substantial uncertainty for developers, landowners, counties, and lenders evaluating solar projects throughout Illinois. There has been a considerable uptick in solar siting litigation across the state as courts (and litigants) grapple with the new state law and the conflicting appellate decisions. 

Supreme Court Review

While the Illinois Supreme Court also considered a petition from Grundy County in Equity Solar, the court granted only the plaintiff developers’ petition in Tate Road Solar. In doing so, the court has elected to review the Fourth District’s interpretation of Section 5-12020 and the extent of county authority over commercial solar projects.

Although the court has not yet addressed the merits of the appeal, its review presents an opportunity to resolve several significant questions, including:

• Whether counties possess discretionary authority to deny solar projects that satisfy statewide siting standards.
• Whether the statutory directive that qualifying projects “shall be approved” imposes a mandatory duty on local governments such that mandamus is an available remedy when a county denies a solar project that complies with state requirements.
• How statewide siting standards interact with local zoning and special use permit procedures.
• What types of requirements counties can impose for the siting of solar projects. 

Briefing in the case will likely run through the end of 2026, with oral argument likely in Spring 2027. The court will issue a written opinion, likely in late 2027.

The court’s decision could significantly impact pending solar development projects and future permitting disputes across Illinois.

Why It Matters

The Illinois General Assembly enacted Section 5-12020 to create a statewide framework for commercial solar siting while preserving a role for local governments. Since its enactment, counties and developers have differed sharply on the extent of local discretion permitted under the statute. The Supreme Court’s review of Tate Road Solar is widely expected to provide much-needed guidance on that issue. A definitive ruling could determine the future of solar siting in the state.

Notably, recent amendments to the Counties Code adopted similar statewide standards for battery storage facilities. Accordingly, the court’s ruling in Tate Road Solar will likely have implications well beyond solar siting. 

Until the Supreme Court issues its opinion, developers should continue to closely evaluate project-specific permitting risks, particularly in jurisdictions where local officials may seek to exercise discretion beyond the statewide standards.

Key Takeaways

• The Illinois Supreme Court granted the Petition for Leave to Appeal in Tate Road Solar on September 30.
• The appeal will allow the court to address the conflict between the Third and Fourth District Appellate Courts regarding solar siting permits.
• The court’s decision is expected to clarify the extent of county discretion under Illinois’ solar siting statute.
• The outcome could have significant implications for solar development, local government authority, and permitting litigation across Illinois.

This is a developing matter, and we will continue to monitor the appeal and provide updates as the case proceeds before the Illinois Supreme Court.