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MPSC sets public hearing on plan for new 679 area code overlay for Detroit's 313 area code

Media contact: Matt Helms 517-284-8300  

Customer Assistance: 800-292-9555  

The Detroit area’s 313 area code is projected to run out of unassigned telephone numbers in 2025, so the Michigan Public Service Commission will hold a public hearing in Detroit in March to take public comment on a proposal to add an overlay area code covering the city and several of its immediate suburbs (Case No. U-21337).

The Commission today set a public hearing for March 9, 2023, 1:30-3 p.m. at Wayne County Community College District’s downtown campus, in the Frank Hayden Community Room #236, 1001 W. Fort St in Detroit. An administrative law judge will conduct the hearing, and MPSC Staff will provide a presentation outlining the issue.

The 313 area code is projected to be exhausted during the third quarter of 2025, which means most phone numbers within the area code are in use, with few to no new numbers available to assign, aside from those returned to the numbering inventory and reassigned through standard industry practice.

That will require applying a new area code that will cover the same geographic territory of the 313 area code, without splitting the current area code boundaries or requiring a change of numbers for existing phone users by moving existing 313 phones to a new area code. Rather, current 313 numbers will remain in place while new phone customers in the same territory may be assigned numbers with the 679 area code.

The 313 area code covers Detroit, its enclaves Hamtramck and Highland Park, and the suburbs of Allen Park, Dearborn and Dearborn Heights, Ecorse, the Grosse Pointes, Inkster, Lincoln Park, Redford Township, River Rouge and Taylor.

Besides having two area codes serving these towns, adding the 679 overlay also will require phone users to include area codes for local calls within and between the two area codes — meaning everyone with a 313 or 679 phone number will have to dial at least 10 digits, even for local calls. These calls will continue to be billed as local calls. This change will require the reprogramming of some devices such as auto dialing equipment, medical devices and home security systems to accommodate the additional digits if that equipment is currently programmed to only dial 7 digits.

No changes to customer bills will occur because of this process.

The North American Numbering Plan Administrator (NANPA), the agency responsible for administering telephone numbering plans in the United States, Canada and multiple Caribbean countries, filed a petition with the MPSC in November seeking to implement the 679 overlay. While the overlay was initially sought in 2000, federal number policy changes and numbering conservation efforts delayed the need to implement it. The current NANPA petition explains that customer education, dialing plan best practices, and technical milestones have changed considerably in the past two decades since the overlay was initially sought, and requests some changes to the old plan previously approved by the Commission to bring it up to date.

The Michigan Telecommunications Act grants the MPSC, which provides regulatory support for telecommunications providers, the authority to approve or reject area code changes in Michigan. The new area code would be phased into use, with dates to be determined, should the MPSC approve the overlay.

Any person may attend the public hearing and offer comments on the overlay plan. The MPSC encourages interested parties to become involved in the proceedings, and any person may present data, views, questions and arguments regarding the plan. 

Written comments regarding the plan also may be submitted by 5 p.m. March 20, 2023, by mail to Executive Secretary, Michigan Public Service Commission, P.O. Box 30221, Lansing, MI 48909, or by email to All comments will be made part of the public case file and should reference Case No. U-21337. NANPA and members of the industry who assisted in developing the relief plan will then be given until March 30 to file responses to the substantive comments.

To accommodate the potential 19-month implementation schedule, the Commission will issue a final order by May 31, 2023. 



The Commission today approved amended power purchase agreements, or PPAs, between Consumers Energy and three solar energy providers (Case No. U-20165). The amended agreements, with Calhoun Solar Energy, Cereal City Solar, and Jackson County Solar, arise from interruptions related to supply chain challenges, inflation and interconnection delays that threatened the projects’ viability. The amendments increase the energy purchase prices in each PPA while shortening the terms of the contracts. According to Consumers, the costs to customers will decrease by $2.4 million in the Calhoun Solar PPA, $4.6 million in the Cereal City PPA, and $46.3 million in the Jackson County PPA.



The Commission denied a petition for a rehearing in DTE Electric Co.’s 2020 power supply cost recovery (PSCR) reconciliation (Case No. U-20528). The Association for Businesses Advocating Tariff Equity (ABATE) had sought a rehearing of the Commission’s rejection of ABATE’s recommendation that the utility offset capacity-related power supply costs from zonal deliverability benefit credits and zonal deliverability charges in DTE Electric’s PSCR reconciliation, related to an extended outage at Unit 3 of the Ludington Pumped Storage Plant. The Commission found that the record clearly addresses ABATE’s arguments and that the Commission committed no error in adopting the recommendation of the administrative law judge on the issue. 



As part of the MPSC’s ongoing New Technologies and Business Models workgroup in the MPSC’s MI Power Grid initiative and its examination of the development of alternative business models, the Commission today summarized comments it received from stakeholders on behind-the-meter distributed energy resources and asked commenters to address several additional questions (Case No. U-20898). Those interested in filing comments must do so by 5 p.m. Feb. 17, 2023, by mail to Executive Secretary, Michigan Public Service Commission, P.O. Box 30221, Lansing, MI 48909, or by email to All comments should reference Case No. U-20898. This MI Power Grid workgroup was established to address preparing for opportunities and challenges associated with commercialization of new technologies and business models such as electric vehicles, electric storage, microgrids, space and water heating using heat pumps, and others still under development.



The MPSC today approved Consumers Energy Co.’s power supply cost recovery plan for the 12-months period ending Dec. 31, 2022, and accepted the utility’s 5-year forecast (Case No. U-21048). Today’s order approves a 2022 PSCR factor of $0.00177 per kilowatt-hour. Intervenors in the case were the Michigan Department of Attorney General; Citizens Utility Board of Michigan; the Association of Businesses Advocating Tariff Equity; Residential Customer Group; Michigan Power LP, and Ada Cogeneration LP. MPSC Staff also participated.


To look up cases from today’s meeting, access the MPSC’s E-Dockets filing system.

Watch recordings of the MPSC’s meetings on the MPSC’s YouTube channel.


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DISCLAIMER: This document was prepared to aid the public’s understanding of certain matters before the Commission and is not intended to modify, supplement, or be a substitute for the Commission’s orders. The Commission’s orders are the official action of the Commission.


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