PJM proposes cluster-based method to replace serial interim deliverability studies starting 2027/28
The Manual 14-H redline would prioritize projects already provisionally operational for deliverable-megawatt allocation, with PJM reverting to a single-cluster study if stakeholder support falls short.
PJM proposes to transition the Interim Deliverability Study methodology from serial to a cycle-based (cluster) methodology starting with the 2027/28 Interim Deliverability Study.1
The proposed manual change affects Manual 14-H Section 4.10.1.3.2
The document lists an effective date of September 15, 2026 for the manual changes.3
Under the proposed methodology, Subcluster 1 includes projects already provisionally operational based on the prior Delivery Year's Interim Deliverability Study results.4
Under the proposed methodology, PJM first evaluates and assigns deliverable megawatts to Subcluster 1 projects, allocated proportionally by each project's MW impact to the flowgate and distribution factor.5
Under the proposed methodology, Subcluster 2 projects are assigned deliverable megawatts only to the extent megawatts remain available after Subcluster 1's allocation is complete.6
PJM says that if stakeholder support for the proposed cluster-based methodology is insufficient, it will instead run the 2027/28 Interim Deliverability Study with all requests in a single cluster.7
Under the status quo, if the proposed cluster-based methodology lacks sufficient stakeholder support, PJM will perform the 2027/28 Interim Deliverability Study on a single-cluster basis, under which projects that are provisionally operational based on IDS results may face a higher likelihood of curtailment, including possible cessation of generation.8
Project developers have expressed concern about the operational and financial impacts of being required to cease generation after previously being deemed deliverable.9
The application window for the 2027/2028 Interim Deliverability Study closed June 30, 2026, and PJM must complete that study by October 2026.10
PJM says that if the proposed Manual 14-H revisions are approved, no additional action will be required from project developers who already submitted 2027/28 IDS requests.11
Gridlight analysis
Interpretation by Gridlight, resting on the documents in Sources.
Whether stakeholder support for the proposed cluster-based methodology proves sufficient is not resolved by these materials, and that determination decides which of the two methodologies described above governs the 2027/28 Interim Deliverability Study.■■■■■■■■■■■
Coverage notes
Gridlight’s notes on what we looked for and did not find; these statements are Gridlight’s own and are not claim-checked against archived sources.
- Whether the Markets and Reliability Committee approves the redline is not established in these materials.
- What recourse, if any, Subcluster 2 projects have if Subcluster 1's allocation exhausts the available deliverable megawatts is not addressed beyond the allocation order itself.