Grid · Analysis
I.How the line actually works
PJM used to study projects more or less one at a time, in the order they arrived. That worked when a few large gas or coal plants joined each year. It broke down when thousands of smaller solar and battery projects lined up at once, each one waiting on the study of the project ahead. So PJM stopped taking new requests the old way and, with approval from the Federal Energy Regulatory Commission in 2022, switched to studying projects in groups, a method it calls cluster study (the grid operator analyzes a whole batch of projects together instead of one by one).
The trade is honest to state. Clustering should move more projects through at once, but to start it PJM had to pause new requests and work off the backlog first, a stretch it calls the transition period. At last public report that backlog ran to a few thousand projects, the large majority of them solar, batteries, or the two combined. Most will never get built, because a spot in the queue is a request, not a promise.
II.What the wait means for a local project
For a warehouse solar plan in the Delaware Valley, the queue is the part of the schedule nobody controls from here. A developer can line up the roof, the financing, and the buyer for the power, then wait years for PJM to finish the cluster study and hand over a cost for any grid upgrades the project triggers. That upgrade cost is the other surprise: it can be small, or it can be large enough to kill the project outright, and you often don't know which until the study is done.
This is why honest developers in the region talk in cycles, not calendar dates. PJM runs its transition studies in phases, and a project's real timeline depends on which cycle it landed in and how many neighbors share its slice of the grid. If someone tells you a local battery project will be online next year, ask whether it has cleared its PJM study or is still waiting in line. The answer usually explains the rest.
III.How to check a project yourself
Anyone can read PJM's planning queue, and it's open to the public. Each project carries a queue number, a county, a fuel type, a requested size in megawatts, and a status that tells you how far along the study is. For a project you've read about near Philadelphia, you can usually find it by county and by the developer's name, then watch its status change over the months.
Read it with care. A megawatt figure on the queue is what the developer requested, not what will get built, so treat it as roughly true at best. And a project can sit at the same status for a long time, which is normal during the transition, not a sign that something has gone wrong. The queue tells you where the line is, not when your project reaches the front.
IV.Worth watching this month
1. Watch PJM's planning committee materials, posted on its site before each monthly meeting, for updates on where the transition study cycles stand.
2. Check whether FERC has acted on any pending PJM interconnection filing, since the rules for the line can still change and that matters more than any single project.
3. Scan the public queue for new or updated entries in Philadelphia, Delaware, Chester, Montgomery, and Bucks counties, which is routine but shows what is trying to get built here.
4. Watch for any PJM announcement on when it will reopen the queue to new requests, a date that has moved before and may move again.
5. Follow PECO's own interconnection updates if your interest is rooftop or small commercial solar, since that line runs separately from PJM's and moves on its own schedule.
Frequently asked questions
- Does my rooftop solar have to wait in the PJM queue?
- Almost certainly not. Small rooftop systems connect to PECO's local distribution wires under Pennsylvania's interconnection and net metering rules. The PJM queue is for larger generation that ties into the high-voltage grid.
- How long is the wait right now?
- It depends on the cycle a project is in and the grid around it, so there is no single number. Large projects commonly wait on the order of a few years. PJM's own schedule for the transition study cycles is the best public guide.
- Does a spot in the queue mean the project will get built?
- No. Many projects in the queue drop out, often because the study turns up grid upgrade costs the developer will not pay. A queue position is a request to be studied, not a commitment to build.
- Why is PJM in charge of this, and not the state?
- PJM runs the regional high-voltage grid across many states under federal oversight from FERC. Pennsylvania regulates PECO's local wires and retail rates, but the interconnection of large generators is PJM's job.
Sources on the bench
PJM Interconnection, Planning Queue (grid operator) The public list of projects waiting to connect, searchable by county, fuel type, size, and study status. · www.pjm.com/planning/services-requests/interconnection-queues
PJM Learning Center, interconnection basics (grid operator) Plain explanation from the grid operator of how a project joins the system and why the study exists. · learn.pjm.com/three-priorities/buying-and-selling-energy/generation-interconnection.aspx
Federal Energy Regulatory Commission, generator interconnection (.gov) The federal regulator that approved PJM's move to cluster study and that rules on changes to the process. · www.ferc.gov/electric-transmission/generator-interconnection
Pennsylvania Public Utility Commission, net metering (.gov) State rules for customer-owned solar that connects to local wires, the path most rooftop systems take. · www.puc.pa.gov/consumer-info/electricity/net-metering
PECO, generation and interconnection for customers (utility) The local utility's own information for connecting rooftop and small commercial solar, separate from the PJM queue. · www.peco.com/smart-energy/innovation-technology-report/solar-and-renewable-energy