Utility interconnection timelines: what DTE, Consumers Energy, PG&E, SCE and SDG&E say

What the utility step is

Interconnection is the utility’s approval to connect your system to its grid and run it. It’s separate from the city’s electrical permit and from the installer’s license, and each utility sets its own forms, fees and clocks, so a system can be finished on the roof while the utility’s review is still open. Ask your installer who files the application. The utility’s clock starts when a complete one arrives, and the sections below give each utility’s own figures, state by state.

Michigan: DTE Electric

DTE’s Level 1 and Level 2 interconnection procedures, dated July 1, 2026, list the combined Rider 18 applicant cost as “Application Level 1 $50, Level 2 $50.” Other tracks cost more: a non-Rider-18 certified DER track is $100 plus $1 per kWac review, with a $1,000 supplemental review and a $300 study track. DTE’s supplemental procedures say there are no additional application fees for that program, though study or construction fees may apply if triggered.

The clock, as DTE publishes it:

1. Within 10 business days of a complete application and fee, DTE says whether the application is conforming, incomplete or non-conforming.
2. The applicant has 60 business days to fix deficiencies, with up to 2 resubmissions.
3. After approval, the installer has 180 days to install and upload an approved electrical inspection sticker signed by the local governing authority.
4. DTE’s overview says “The interconnection process takes approximately six weeks.”

The 10 and 60 business days come from the July 1, 2026 procedures. The six weeks and the 180 days come from DTE’s undated overview, so read six weeks as DTE’s general statement and not a deadline. DTE’s overview also says the customer, not the installer, signs the Parallel Operating Agreement.

Once you’re connected, DTE says the first Rider 18 bill takes one to two billing cycles. Rider 18 is for generation up to 550 kW, and a generator is eligible when expected generation does not exceed 110 percent of annual consumption.

Michigan: Consumers Energy

Consumers Energy’s distributed generation program has three levels: Level 1 up to 20 kW, Level 2 over 20 to 150 kW and Level 3 over 150 to 550 kW. Its cost table lists the distributed generation application review at $50, with the supplemental review, system impact and facilities study at $0. Other tracks cost more: a pre-application is $300, and an initial review is $100 plus $1 or $2 per kWac. Level 1 can be filed online through PowerClerk.

The steps on Consumers’ page are the application, a check that the system matches approved specs, a commissioning test and signing the Generator Interconnection Operating Agreement.

Consumers’ pages don’t print a review timeline for Level 1 applications, so ask your installer for the filing date and Consumers for the expected approval date.

Michigan: other utilities, and what the state says

The MPSC says each utility filed an updated distributed generation tariff for Public Act 235 of 2023 and that all of them were approved on March 13, 2025: Consumers Energy (U-21796), DTE Electric (U-21798), Indiana Michigan Power (U-21795), UPPCO (U-21791), Alpena (U-21794), NSP (U-21793) and UMERC (U-21790). If your electric service comes from one of the others, use that utility’s own application page. Customers must interconnect before operating.

For the credit rules that follow interconnection, see net metering and distributed generation. For the city side, the permit is pulled under the contractor’s state license number, covered in how solar permits work in Michigan. The interconnection and permits service page lists the steps in order.

California: Rule 21 and the three large utilities

In PG&E, SCE and SDG&E territory, interconnection runs under Rule 21, the CPUC tariff that describes the interconnection, operating and metering requirements for generation facilities connecting to an investor-owned utility’s system. LADWP and SMUD are municipal utilities with their own rules.

PG&E

After PG&E receives the required paperwork from the contractor, permission to operate “typically takes 5 to 10 business days, up to a maximum of 30 business days.” PG&E states a $145 interconnection application fee for NEM2 systems of 1 MW or less, and the CPUC lists $145 for PG&E. PG&E asks contractors to put customer and contractor e-mails on the application for faster approval by e-mail.

PG&E also says NEM applications submitted before April 15, 2023 had to be completed before April 15, 2026 to be eligible for NEM2; from April 15, 2026, NEM2 interconnection applications transition to the Solar Billing Plan.

SCE

SCE says simple and standard solar-only requests with all the correct information and required documents may receive permission to operate within 10 business days; paired storage or non-standard metering will need more time. Its Solar Billing Plan factsheet says most customers receive permission within 10 business days, but the current review time may take up to 30 business days. The CPUC lists $94 as SCE’s fee. First-year enrollees on the Solar Billing Plan get an extra $0.04 per kWh export credit, or $0.09 for low-income residential customers.

SDG&E

SDG&E’s generator interconnection overview of October 2024 says it issues initial review results within 15 business days of a complete and valid interconnection request, and supplemental review results within 15 business days after the review. The fee is $132 for systems of 1 MW or smaller, as of SDG&E’s 2023 page, and the CPUC table lists the same figure; larger systems are $800.

The tariff behind the application

The net billing tariff applies to customers applying for interconnection since April 15, 2023, and the date of your application matters. The CPUC says NEM tariffs are closed to new enrollments, and customers already on NEM 2.0 may remain on it for 20 years from the date they interconnected. Net metering and distributed generation explains the credits.

SMUD

SMUD’s battery page says customers must enroll within 90 days of permission to operate to get its upfront incentive. SMUD is municipal and outside the CPUC’s net billing tariff.

What to ask your installer

Ask who files the utility application, which level and fee apply, the date it was filed and the date permission to operate is expected. Keep those dates in your own notes next to the contract. If the installer’s estimate is longer than the utility’s published range, ask what’s driving it.