Public Service Commission of Wisconsin Issues New Application Filing Requirements for Energy Storage Projects

On April 7, 2026, the Public Service Commission of Wisconsin (“Commission”) issued a new order establishing detailed Application Filing Requirements (“AFRs”) for energy storage projects in Wisconsin. These new AFRs apply to:

1. Standalone energy storage projects, including battery energy storage systems (“BESS”).
2. Energy storage projects proposed in combination with generation or transmission projects; and
3. Energy storage projects developed by Wisconsin public utilities and independent power producers.

The Commission will expect any application for an energy storage project requiring either a Certificate of Authority (“CA”) or a Certificate of Public Convenience and Necessity (“CPCN”) to follow these requirements. If an energy storage project is part of a larger generation or transmission project, the Commission recommends that applicants combine their energy storage project application materials into the relevant sections of the generation or transmission application “in the most logical manner possible.”

The newly adopted AFRs require applicants to address a comprehensive set of environmental, safety, and community-impact topics. Many of these requirements are similar to existing generation AFRs. For example, Section 2.7 of both the wind and solar generation AFRs covers co-located BESS. The energy storage project AFRs expand upon existing requirements, as they are technology-neutral (not just BESS), apply to stand-alone energy storage projects (not just co-located), and expand the scope of required disclosures for energy storage projects.

Below is a summary of the major components of the AFRs.

1. Project Area and Site Alternatives

The Commission is required to evaluate alternatives for projects that require either a CPCN or a CA. Like with generation projects, the AFRs require energy storage project applicants to present this analysis in a structured and transparent way. Applicants must describe where the project is proposed to be built and why the site was selected; this includes the proposed alternative sites and an explanation as to why the proposed site is preferable to alternatives.

2. Project Overview

The Commission uses the project overview section to obtain foundational project information. The overview should detail the project’s facilities and sites, the process for selecting those sites, a list of agency permits and approvals the applicant believes may be necessary to properly site and operate the project, project area mapping, and GIS data.

3. Project Need and Market Context

For utility-owned projects, applicants must explain the need for the project and how the energy storage system fits into long-term resource planning. Utility-owned projects must also describe the non-energy storage supply alternatives and discuss why no-build alternatives are insufficient. This requirement does not apply to independent power producers.

The Commission expanded the requirement to evaluate an energy storage project’s effect on wholesale market competition. The AFRs require an applicant in certain circumstances to provide “an analysis of the Herfindahl-Hirschman Index market concentration impact of the proposed project.” This analysis measures whether a project will increase or decrease wholesale electricity market competition. The Commission’s solar and wind generation AFRs do not contain this requirement.

4. Project Engineering and Technical Description

The AFRs require energy storage project applicants to provide similarly detailed engineering information to the existing large generation facility AFRs.

Applicants must provide detailed technical information on the energy storage system’s performance characteristics, operating profiles and usage, equipment layout and physical dimensions, and interconnection approach and grid interaction.

Applicants must also provide relevant information on any transmission interconnections, substations, and operations and maintenance buildings required for the project.

5. Project Costs

All utility applicants must detail the project’s costs. This includes capital and construction costs, the proposed method for financing the project, forecasted costs, and, if applicable, transmission costs. This requirement does not apply to independent power producers.

6. Safety, Fire Protection, and Emergency Response

The AFRs require applicants to address a variety of compliance standards, including the adequacy of the project’s fire detection and suppression systems. Applicants must also detail the project’s compliance with recognized testing protocols, emergency response planning, and coordination and training with local first responders.

7. Site Construction and Information

Applicants must also provide details on access routes, the construction workforce, duration of construction, and erosion control measures. This information allows regulators to distinguish short-term construction impacts from long-term operations.

8. Natural Resource Impacts

The AFRs require a natural resource impacts analysis that the applicant conducts in coordination with the Wisconsin Department of Natural Resources (“DNR”). Applicants must describe how forested and grasslands are impacted by the project. The application must also include details on invasive species that may concern the project and how the applicants will re-vegetate and restore land post-construction.

9. Community Impacts and Land Use Compatibility

The AFRs require significant information on the energy storage project’s community impacts and outreach done by the developer. This includes discussions of zoning ordinances affecting the project area, setback distances for residential areas, and impacts to the area’s aesthetics, parks, and recreation areas. Applicants must also discuss the existing infrastructure of the area and prepare noise evaluations to assess expected operational noise levels.

10. Wetland and Waterway Permitting (DNR Coordination)

The AFRs provide guidance for applicants on preparing information required by DNR for wetland and waterway permits. Where applicable, applications must include detailed wetland and waterway delineations, GIS mapping, impact tables, and endangered-resources screenings and surveys.

11. Endangered Resources and Species Protection

The AFRs provide guidance on how applicants should perform an Endangered Resources screening, if required. The Endangered Resources screening should provide an evaluation of the project’s impacts to federally and locally threatened or endangered species.

Applicants developing energy storage systems in Wisconsin should prepare themselves for the new requirements and take the time to thoroughly address all requirements prior to applying to the Commission. Complying with the AFRs will likely lessen the amount of subsequent data requests and expedite a completeness determination once the application is filed.

Our energy regulatory team is actively assisting clients with strategic compliance planning, application preparation, and regulatory risk management for energy storage projects in Wisconsin and across the Midwest. If you have questions about how these new requirements affect your current or planned projects, please contact us.