PJM's first cycle under the reformed interconnection process is now in study. PJM Cycle 1 Phase I began on September 28, 2026 and is expected to conclude on March 26, 2027. The Interconnection Process Subcommittee met on October 23. PJM said updated models and case files would post in mid-November. For a Pennsylvania solar developer with a project in the cycle, the next five months are not a waiting room. They are the stretch where a drawing change is most expensive.
In August, PJM said 715 new generation projects totaling more than 200 GW qualified to be studied in Cycle 1. Solar accounted for 117 of them. Our earlier post on the 715 projects accepted into PJM Cycle 1 covered the intake. This one is about what to stop editing now that study has started.
PJM Cycle 1 Phase I dates to put on the wall
These are the dates from PJM's October subcommittee material, as summarized publicly after the October 23 meeting.
- September 28, 2026. Cycle 1 Phase I began.
- Mid-November 2026. Updated models and case files posting for Cycle 1 and for Transition Cycle 2.
- November 23 and December 21, 2026. The next Interconnection Process Subcommittee meetings.
- March 26, 2027. Expected end of Cycle 1 Phase I.
Transition Cycle 2 is on its own clock. Its Phase III began July 8, 2026 and is expected to finish March 5, 2027, with Decision Point III from March 8 to April 6, 2027. If your company has projects in both tracks, keep them in separate folders. The deadlines are close enough to confuse and far enough apart to miss.
What should be frozen during Phase I
PJM is studying the project you submitted. The engineering package that supports it should describe that same project until a decision point gives you a sanctioned way to change it. In practice that means these items stop moving:
- Point of interconnection. The substation or line and the description used in the application.
- Maximum facility output. The MW that PJM is studying, written the same on the one-line, the site plan, and the application.
- Collector and step-up design. The transformer rating and configuration on the one-line.
- Storage. If the project is a solar and battery hybrid, the battery rating and how it charges.
Storage deserves a second look this cycle. PJM's winter deliverability methodology for solar and battery hybrids applies to Transition Cycle 2 Phase III models and beyond, and to the 2027 RTEP studies. A hybrid that is drawn one way and described another way in the model is a hybrid that will get questions.
The local permit runs in parallel, not after
A PJM queue position does not zone the land. Pennsylvania townships still control zoning and land development, and a project that disturbs an acre or more needs an NPDES permit for stormwater from construction activity. Those reviews read a site plan. That site plan should show the same array, the same equipment pad, and the same collector route as the package PJM is modeling.
Athol Energy prepares commercial and utility plan sets and the electrical drawings that sit behind a transmission-level application. We do not represent projects at PJM. Our job is the drawing side, so the site plan a township reviews and the one-line PJM studies are the same project.
The commercial utility solar plan set post explains how those sets break when a civil sheet and an electrical sheet are revised by different people. Phase I is the time to prevent that. Put the studied MW in the revision block. Any sheet that states a different number is wrong.
Distribution projects are a different filing
Not every Pennsylvania solar project goes to PJM. A rooftop or small ground-mount that connects to PPL, PECO, or FirstEnergy Pennsylvania distribution goes through the utility's Chapter 75 process instead. Our post on York Pennsylvania solar interconnection covers that path. If a project could go either way, decide which one it is before anyone draws a one-line. The Pennsylvania commercial solar interconnection post covers the middle ground.
Questions about PJM Cycle 1 Phase I
When does PJM Cycle 1 Phase I end?
Phase I began September 28, 2026 and is expected to conclude March 26, 2027.
How many solar projects are in Cycle 1?
PJM said in August 2026 that 715 projects qualified for Cycle 1. Solar made up 117 of them.
Does the winter deliverability method affect hybrid projects?
Yes. PJM's winter deliverability methodology for solar and battery hybrids applies to Transition Cycle 2 Phase III models and beyond, and to the 2027 RTEP studies.
If a Pennsylvania project is in Cycle 1 and the drawings are still being edited, freeze them now. Pennsylvania solar design from Athol Energy keeps the one-line, the site plan, and the township set on one MW figure. Contact us.