137-CE-212

Key events and submissions in the Mill Rd to Granville Rebuild project proceeding (Docket 137-CE-212) include:

- The CPCN (Certificate of Public Convenience and Necessity) application was determined complete by the Public Service Commission of Wisconsin (PSCW), triggering a statutory 180-day review period. This initial 180-day deadline to take final action was set to expire on May 21, 2025. However, due to the project’s size and complexity, the PSCW requested and received an extension, moving the final action deadline to November 17, 2025 1, 1.
- A prehearing conference was held on February 17, 2025, setting out participation and filing requirements for all parties and intervenors 2.
- Evidence and testimony schedule:
- February 28, 2025: Direct testimony from the applicant
- April 11, 2025: Direct testimony from intervenors and commission staff
- May 12, 2025: Rebuttal testimony from parties and commission staff
- May 27, 2025: Surrebuttal testimony from parties and commission staff
- May 28–June 3, 2025: Additional evidence, errata, witness affidavits, and revised testimony submitted and hearings conducted
- June 5–9, 2025: Transcript corrections and objections
- June 19, 2025: Initial brief due
- July 3, 2025: Reply brief due 3.

Further events will depend on the commission’s review process and any extensions or additional hearings as required by the proceeding schedule.

Docket 137-CE-212 concerns the application by American Transmission Company LLC (ATC) for a Certificate of Public Convenience and Necessity to construct and operate the Mill Road–Granville transmission line project in Wisconsin. The primary scope includes:

- Constructing a new greenfield Mill Road substation with 345 kV and 138 kV ring buses and an autotransformer.
- Rebuilding the existing double-circuit 345/138 kV transmission lines as double-circuit 345 kV lines (W-42/W-43) between Mill Road and Granville substations (7.5 miles).
- Constructing new 138 kV transmission lines from Mill Road to Tamarack (X-196, 1.5 miles) and Tamarack to Butler (X-197, 5 miles).
- Modifying and expanding the Granville, Butler, and Tamarack substations.
- Reconductoring and uprating additional 138 kV and 345 kV circuits and modifying some existing lines and substations to accommodate the new configuration.
- Minor remote end work at other substations in the region 1, 2.

Environmental review concluded that the project will not result in significant impacts to the human or natural environment and that preparation of an Environmental Impact Statement (EIS) is not required. Impacts include temporary visual and noise disturbance, limited permanent wetland fill, tree clearing, and construction-related disruptions, but these are not expected to be significant if proposed mitigation measures are followed 2.

The project addresses reliability issues in the western Milwaukee transmission system, as identified in MISO’s 2023 and 2024 Transmission Expansion Plan reports. Engineering analysis confirmed that without these upgrades, the system would not comply with NERC reliability standards, particularly regarding thermal overloads during contingency events. The proposed alternatives effectively mitigate these violations 3.

The docket includes requirements and recommendations for mitigation, competitive bidding transparency, vegetation management, and coordination with federal and state agencies regarding environmental and wetland impacts 4, 5, 6. Public hearings and opportunities for public comment were provided as part of the regulatory process 7.

Financial and timeline risks and concerns discussed in the Mill Road–Granville transmission line project docket include:

Timeline Risks and Concerns:
- The statutory timeline for the Public Service Commission (PSC) to take final action on the Certificate of Public Convenience and Necessity (CPCN) application is 180 days from the application being deemed complete. However, due to the project's size, the need for an environmental assessment, preparation of testimony, public hearings, and commission staff workloads, an extension of an additional 180 days was requested. If granted, this would move the final decision deadline to November 17, 2025. The need for the extension itself is identified as a timeline risk, with commission staff noting they are working diligently but acknowledging the complexity and volume of tasks required for review 1.

Financial Risks and Concerns:
- There is a concern regarding visibility into project construction costs. Commission staff recommended an order condition requiring the applicant to provide a summary of competitive bids received for work and equipment procurement. This recommendation comes from a recognition that not all contracts are competitively bid, and increased transparency is needed to better monitor and manage construction costs 2.
- The potential for increased project costs is also referenced in the context of possible order conditions and construction adjustments, though specific cost figures or overruns are not detailed in the provided excerpts 2.

These risks reflect both potential schedule delays due to procedural and regulatory requirements, and concerns about cost control and transparency during the bidding and construction process.

The docket identifies several areas of growth, each with specific key considerations:

1. New Large Load Additions (Data Center in Southeast Wisconsin)
- A significant new data center load in the EITM zone, scheduled to come online between 2025 and 2027, is a major driver of growth. This load is described as significantly larger than those in Madison or Milwaukee, operating 24/7/365.
- Key considerations: The new load will further stress the existing transmission facilities, exacerbate existing reliability issues, and requires transmission system upgrades to ensure compliance with NERC reliability standards and reliable service delivery 1, 2.

2. New Generator Interconnections (Primarily Renewable Generation)
- Numerous requests for new generator interconnections, especially renewable generators north and west of the study area, have been submitted. MISO’s planning studies have identified system limitations that necessitate network upgrades to support these new generators.
- Key considerations: The project is required to accommodate these new interconnections, address limitations caused by increased north-to-south power flow, and is listed as a required network upgrade for multiple executed Generator Interconnection Agreements 1, 1.

3. Asset Renewal
- Many existing transmission facilities in the area are aging (1960s–1970s vintage) and approaching the end of their useful life.
- Key considerations: While not the primary driver, asset renewal is incorporated where it can optimize project scope and efficiency. Replacement is guided by both age and condition, and coordinated with other ongoing asset renewal projects in the area 1, 1.

4. Transfer Capability and Congestion
- Historical congestion due to limited transfer capability in the western Milwaukee area has been a focus for transmission planners.
- Key considerations: Enhancing transfer capability through system reinforcement will reduce congestion, improve local and regional reliability, and support economic and operational flexibility 1, 1.

In summary, the primary areas of growth are large new load interconnections (such as data centers), new generator (especially renewable) interconnections, the need for asset renewal of aging infrastructure, and increased transfer capability to reduce congestion. Each area requires upgrades to maintain reliability, accommodate expansion, and ensure efficient operation of the regional grid.

Stakeholders in this docket (137-ce-212) for the Mill Road–Granville transmission line project include:

- American Transmission Company LLC (ATC): The applicant proposing the project, which includes constructing two new 138 kV transmission lines, rebuilding two existing double-circuit 345/138 kV transmission lines, and constructing the 345 kV Mill Road Substation. ATC supports the project as proposed and asserts it is in the public interest 1.

- Wisconsin Public Service Commission (PSC): The regulatory body reviewing, holding hearings, and issuing orders about the project. PSC staff provide testimony, data requests, and recommendations, but do not advocate for or against the project itself.

- Local landowners and businesses: Several landowners and business owners along the proposed and alternate routes are stakeholders. For example:
- Paul and Jennifer Todd, business owners on the preferred proposed route, oppose aspects of the proposal that would add towers to their property, reduce usable space, and require additional easements limiting their future growth plans 2.
- The Dominski Revocable Living Trust, Gregg and Jennifer Weymiers, and the Fleisner Living Trust have raised specific concerns about route alignments and impacts to their properties, seeking alternate routes or adjustments to minimize impacts (e.g., tree clearing) 3.

- Municipalities and local officials: Notification was sent to relevant county and municipal officials and staff. Their official positions are not detailed in the excerpts, but they are recipients of project communications and may participate in the process 1.

- General public: Public hearings have been held, with opportunities for comments both in person and online. Individual comments for or against the project are not summarized in detail in the excerpts, but public involvement is documented 4, 5.

- Environmental and regulatory agencies: Agencies involved in permitting, environmental review, and avian protection consultations are stakeholders but no specific positions are stated in the excerpts.

- Pipeline operators: ATC has had initial discussions with them about right-of-way and safety issues; their positions on the project overall are not specified 6.

Positions for or against specific proposals:

- ATC supports the proposed route as being in the public interest 1.
- Some landowners and businesses along the route oppose aspects that impact their property or business operations and advocate for alternate routing or modifications 3, 2.
- PSC staff provide analysis and recommend order conditions for cost reporting and environmental mitigation but do not explicitly support or oppose the project as a whole 7, 8.

No excerpts document organized opposition or support from municipal governments or environmental organizations. Detailed positions of individual public commenters are not included in the provided excerpts.