Renewable energy: Customer owned generation (Wisconsin)

If you are installing your own generation with a capacity of up to 15 megawatts (MW), whether it is rooftop solar, a micro wind turbine or fuel cell to your home or business, you and your installer must follow the Public Service Commission of Wisconsin (PSCW) interconnection rules. In addition, you must meet all of Alliant Energy's tariff requirements.

Customers are encouraged to check with Focus on Energy, Wisconsin utilities' statewide program for energy efficiency and renewable energy, for potential grants and available incentives.

You and your installer are responsible for coordination of design, installation, operation and maintenance of any generation system you install, and for conforming to the requirements of our tariffs and rules and applicable governmental laws and regulations (local, state and federal).

These requirements are designed to protect distribution facilities; avoid electrical interference problems; ensure the safety of customers, electric provider employees and the general public; and maintain overall system reliability.

You are required by law to maintain liability insurance (equal to or greater than the amounts indicated in [IAC 199.45] for Iowa customers, [PSC 199] for Wisconsin customers) or to prove financial responsibility by another means agreeable to us. You are required to notify us if a material modification is made to your generation facility at any time during or after the installation process. A material modification is any modification that changes the maximum electrical output of your facility or changes the interconnection equipment, including:

• Changing from certified to non-certified devices.
• Replacing a component with a component of different functionality or UL listing.

You also are responsible for the proper installation, operation and maintenance of the specified protective devices. Finally, you shall obtain at your expense any and all authorizations, permits and licenses required for the construction and operation of your generation facilities.

We are responsible for promptly carrying out the steps listed below and for meeting all required steps and timelines to process your interconnection application.

To comply with the interconnection agreement, you must maintain the required liability insurance. Proof of insurance showing the appropriate liability is based on category.

category	generation capacity (ac)	minimum liability insurance coverage
1	20kW or less	$300,000
2	Greater than 20kW to 200kW	$1,000,000
3	Greater than 200kW to 1MW	$2,000,000
4	Greater than 1MW to 15MW	Negotiated

Category 2-4 will need to name Wisconsin Power and Light Company with the address shown below as an additional insured party under Additional Interest, Certificate Holder, etc. on the Certificate of Insurance.

Category 2-4 will have to note "Certificate holder is named as an additional insured" in Description of Operation, Remarks, etc. on the Certificate of Insurance.

Please use the following official Alliant Energy Wisconsin utility name and address on the Certificate of Insurance:

Wisconsin Power and Light Company
4902 North Biltmore Lane
Madison, WI 53718

We recommend reading these rules and guidelines before beginning the interconnection process.

NOTICE: As of May 1, 2024, the rules for interconnection of distributed generation systems in Wisconsin (Wisc. Admin. Code Ch. PSC119) have been updated. We are in the process of updating our systems in accordance with those updated rules. When the Public Service Commission makes the newly required Form 6031 available, we will work to incorporate that form as quickly as possible. In the meantime, you may continue to submit applications through our PowerClerk online interconnection application system using the previous Forms 6027 and 6028.

• Alliant Energy DER Technical Interconnection Requirements.pdf
• Alliant Energy Definitions, Acronyms and Abbreviations.pdf
• Alliant Energy Electric Service Rules (includes meter and label diagrams) – Chapter 5, Distributed/Customer-Owned Generation .pdf
• Alliant Energy Electric Service Equipment Manual (includes meter equipment diagrams).pdf

This should provide you a general overview of the interconnection process. Each application is handled on a case-by-case basis and may include additional requirements not mentioned here.

Step 1 – Preapplication process/research

If you are interested in generating your own power, we recommend you read through our helpful information and watch the solar energy video series. This will give you some background information to see if self-generation is right for you and your home. If you decide to pursue installation, these documents will also help you ask the right questions as you search for a reputable installer.

Before you begin your project, gather your historical electrical usage data for your property. Installers require you to provide your electric usage history before giving you an estimate. To help expedite the process, you can find your usage history within My Account or add your installer as a guest user so they can easily have access for the remainder of your project. View our Account and Billing section and click on "Update My Account" within our Help Center.

Step 2 – Submit interconnection application

Once you find an installer, work with them to start your interconnection application with Alliant Energy. They should be able to guide you through the application process or even do it for you and only require you to read over the documents, sign them and provide the applicable fees. You should complete and submit a Standard Distributed Generation Application form, proof of insurance (if required) and other facility information (i.e., one-line diagram, plot plan, and spec sheets for inverter and for solar panels/wind turbines). If any information is missing, the application will be returned as incomplete.

We recommend you and your installer use our Distributed Generation Assist tool to evaluate and refine your distributed generation system’s design. This tool provides guidance about location, size, design and equipment. You’ll get a downloadable summary report to help you avoid common issues our engineers often encounter reviewing interconnection applications.

If they do not do it for you, you can complete the online application and submit it through Power Clerk, our online portal, or mail it along with your application fee to:

Alliant Energy Renewable Hotline
GO-17
P.O. Box 351
Cedar Rapids, IA 52406-0351

Please note: Name and address under "Electric Service Provider" must be to the following on the application form:

Wisconsin Power and Light Company
4902 North Biltmore Lane
Madison, WI 53718

Additional forms (if applicable) can be found at the Public Service Commission of Wisconsin’s Customer-Owned Electrical Generation website.

Step 3 – Application review

If the Standard Distribution Application is incomplete or the fee is not received, Alliant Energy will notify you to resubmit with the needed corrections.

Within 10 working days of receiving a new or revised application, we notify you whether the application is complete. All applications must be signed by you and by us prior to commencing parallel generation. To stay updated on the status of your project, monitor the email you provided on the application (this is the email you gave to your installer).

Step 4 – Engineering review and determination

When your application is complete, we determine whether an engineering review is needed. If an engineering review is necessary, we notify you within 10 business days and state the cost we will charge for that review. Please consider utility input when specifying components to ensure that your components will work on the Alliant Energy distribution system.

Note: If an engineering review is not needed, your application will be deemed “approved” and moved to the next step.

A. Engineering review: After you notify us in writing (email is acceptable) to proceed and submit applicable payment, we will complete the engineering review and notify you of the results.

B. Distribution system study determination: If the engineering review determines that a distribution system study is necessary, we will include a written cost estimate in the review summary.

C. Completion of distribution system study: After you send us written notification to proceed and pay the applicable fee, we conduct the distribution system study. This study assesses the impact your generating system will have once connected to our grid. We provide you with the study results.

D. Notification of construction or modification costs: We notify you of distribution system study results and costs associated with any construction or modifications to our grid. You provide a written agreement to pay for work related to the interconnection modifications and submit payment for required upgrade of our distribution system. After we receive payment, we perform all work needed to upgrade our distribution system to accommodate your generating equipment.

Step 5 – Installation of customer generation

If approved, Alliant Energy will provide you with an Interconnection Approval Memorandum. This Memorandum has terms and conditions for interconnection of your system, as well as a copy of the standard Interconnection Agreement that will be executed upon completion of all requirements.

You now have permission to install your generating equipment within a mutually agreed-upon timeframe. 

Step 6 – System testing and acceptance

Once your construction is complete, you are required to notify us, pay the appropriate commissioning fee, provide us with any test results and give us an opportunity to witness or verify system testing. When we get your notification and payment, we do one (or more) of the following:

• Witness commissioning tests.
• Perform an anti-islanding test or verify protective equipment settings, or
• Waive our right, in writing, to witness or verify commissioning tests.

Please note:  You may be charged for additional commissioning fees if any retesting is required.

We then notify you of our approval or rejection of the interconnection. If approved, we provide a written statement of final acceptance and reconciliation of costs from the engineering review, distribution system study and any required distribution system upgrades or modifications.

If we do not approve the interconnection, you may take corrective action and ask that we re-examine your interconnection request.

Step 7 – Interconnection agreement and completion

After your installation is reviewed and approved, an Interconnection Agreement must be signed by you and us before parallel generation operation commences. If you did not sign and return the draft Interconnection Agreement provided with your interconnection approval memorandum, or if changes were made since that time, you will be provided with a new version of the Interconnection Agreement to sign.

Once all requirements are met and the Interconnection Agreement is fully executed (signed by both you and Alliant Energy), you will receive a Permission to Operate notice.

Your generating equipment should not be in operation prior to receiving Permission to Operate.

While our online PowerClerk application is the fastest and most convenient method, you can also find the standard Interconnection Agreement forms at the Public Service Commission of Wisconsin’s Customer-Owned Electrical Generation website. You can mail the completed Interconnection agreement to:

Mail the completed Interconnection agreement to:

Alliant Energy Renewable Hotline 
GO-17
P.O. Box 351
Cedar Rapids, IA 52406-0351

Please note: If submitting by mail, the name and address under "Electric Service Provider" must be the following on the Interconnection Agreement form:

Wisconsin Power and Light Company
4902 North Biltmore Lane
Madison, WI 53718

Applications and processing times are classified by the size and type of system being installed. Remember if you’ve hired a solar contractor to perform your installation, the contractor will work with Alliant Energy on your behalf, so you must be in constant communication with your installer through every step. To stay updated on the status of your project, monitor the email you provided on the application.

Note: Numbers and types of technical reviews may vary by levels. To help expedite the process, complete and return necessary documents. If documents are incomplete or payment is not received, project duration may be delayed.

Tariff and power purchase information

• Parallel Generation (In Excess of 20kW) – Sheet 7.75, Schedule PgS-1.pdf
• Parallel Generation (20kW or less) – Sheet 7.80, Schedule PgS-3.pdf
• Parallel Generation – Specifications – Sheet 7.90, Schedule PgS-4.pdf

Billing

• Solar energy billing: Your questions answered.pdf
• Understanding your parallel generation bill (sample).pdf
• Wisconsin bill charge example
• Wisconsin bill credit example
• Wisconsin cash out example