PJM is taking another run at a faster interconnection route
The PJM Interconnection is reconsidering how to make better use of spare grid access at existing power plants, a move that could matter for the pace of battery storage and new generation development across the largest U.S. power market. The issue is surplus interconnection service, or SIS, a process that allows a new generator or energy storage project to connect using excess interconnection rights already tied to an existing facility.
In theory, the pathway should be attractive. It can move faster than a standard interconnection study and may reduce or avoid expensive network upgrades, because the project is not asking for a completely new point of connection. In practice, PJM’s version has delivered little. Utility Dive reports that since 2023, PJM has received eight SIS applications and approved only two of them, based on the most recent information cited from a late November presentation.
That weak showing has pushed PJM toward another round of rule changes after an earlier reform effort in early 2025 failed to generate meaningful momentum. The broader significance is straightforward: interconnection has become one of the defining bottlenecks in U.S. electricity development, and any credible shortcut that can bring batteries or generation online faster is likely to draw intense attention.
Why surplus interconnection matters now
The appeal of surplus interconnection service is tied to a structural problem in power markets. Grid operators across the United States face large queues of proposed projects awaiting review. Full interconnection studies can take years, while the need for flexible capacity, reliability support and cleaner generation is immediate. If developers can attach a battery system or another project to an existing plant’s interconnection point, they may be able to cut through some of that delay.
The article says SIS can be significantly faster than standard interconnection reviews. It also notes that using existing capacity can avoid costly upgrades. Those advantages help explain why the pathway is especially relevant for battery storage, which often benefits from being colocated near existing infrastructure and can be paired with legacy assets or hybridized with renewable generation.
PJM’s problem is that its rules have not translated those advantages into actual deployment. The source text says current rules hinder hybrid projects, a major issue in a market where storage increasingly complements solar and other generation. If the framework is too narrow, too uncertain or too administratively heavy, developers may conclude that the supposed fast track is not meaningfully faster at all.
Other grid regions are moving ahead more quickly
PJM’s slow progress stands out because other U.S. regions are processing far larger volumes of surplus interconnection requests. According to the analysis cited in the article, the Midcontinent Independent System Operator, or MISO, was studying 14.8 gigawatts of surplus interconnection requests as of June 30. The Southwest Power Pool, or SPP, was studying 14.3 gigawatts. Western utilities were reviewing 6 gigawatts, and Southeastern utilities were reviewing 1 gigawatt.
PacifiCorp offers another example of scale. As of August 13, it was reviewing 33 projects across five Western states totaling 5.2 gigawatts, according to its surplus queue. In the prior 60 days, it had filed five surplus interconnection agreements for approval by the Federal Energy Regulatory Commission.
The mix of projects is also revealing. The article says the majority of pending surplus interconnection requests in MISO, SPP and PacifiCorp involve battery storage. That suggests developers increasingly view the pathway as a practical route for storage deployment, particularly where existing power facilities already have underused interconnection rights that can be repurposed or shared more efficiently.
Operational results in those regions reinforce that point. The source reports that 44 surplus interconnection projects have come online in MISO and 22 are operating in SPP’s footprint. Since 2024, projects in MISO have taken about one year to come online under this model, according to the report cited by Utility Dive. Those figures do not prove every region can replicate the same pace, but they do show that surplus interconnection is not merely a theoretical policy tool.
What PJM may need to fix
The emerging policy question is why PJM has lagged so far behind. The source material does not provide a full diagnosis, but it points to a few likely pressure points. One is process design. If the rules do not give developers a clear, predictable path to approval, projects that look viable on paper may stall before construction.
Another is project type. Battery storage and hybrid resources do not always fit neatly into legacy interconnection frameworks designed around conventional power plants. A market that wants more flexible capacity has to make room for asset configurations that were once unusual but are quickly becoming normal. If PJM’s surplus process is still built around older assumptions, that could explain why competing regions are pulling ahead.
The article also suggests an information gap. PJM does not publicly release detailed information about surplus interconnection requests beyond periodic updates to its Interconnection Process Subcommittee. Limited visibility can make it harder for developers, policymakers and market participants to assess what is working and what is not. Greater transparency would not solve the queue problem on its own, but it could improve confidence and identify where revisions are most needed.
What happens next matters beyond PJM’s own territory. The organization serves a vast electricity market, and its interconnection policies influence how quickly new capacity reaches the grid in a region under pressure from load growth, reliability demands and changing generation economics. If PJM can make surplus interconnection service function as intended, it could create a faster on-ramp for projects that do not need entirely new transmission access.
That would be particularly important for battery storage, which can support reliability, absorb renewable output and provide operational flexibility. In a constrained grid environment, speed matters almost as much as cost. A workable SIS pathway could help bring projects online while larger transmission and queue reforms continue moving at their usual pace.
For now, the picture is one of underperformance in a market that cannot afford many avoidable delays. PJM’s second attempt at reform will be watched closely because other regions have already shown that surplus interconnection can scale. The question is whether PJM can adapt its rules quickly enough to turn a little-used option into a meaningful piece of the grid expansion toolkit.
This article is based on reporting by Utility Dive. Read the original article.
Originally published on utilitydive.com