A data-center developer pricing a site does not need another summary of why the grid is busy. What it needs is a way to read six filings that arrive within days of each other and decide, region by region, what a megawatt of new load will cost to study, secure and energize while the wires catch up.
On June 18, 2026, the Federal Energy Regulatory Commission opened six separate show-cause proceedings under section 206 of the Federal Power Act, one for each regional grid operator. The dockets run from EL26-67 for PJM through EL26-72 for ISO New England.12 Five operators (PJM, MISO, CAISO, ISO-NE and NYISO) are due to file responses on November 16. Southwest Power Pool, which asked for a slightly longer abeyance, is due on or about November 20.34 Answers and protests are due thirty days after each filing, which puts most comment windows around December 16.3
The filings are not a single national tariff. They are six answers to the same preliminary finding: that each operator's tariff appears unjust or unreasonable without clearer rules for large loads. Until FERC acts, today's tariffs still govern. The scorecard below is for people who have to price that uncertainty.
What FERC said was missing
A show-cause order is a demand for an answer, not a final rate. In each order FERC preliminarily found that the tariff lacked adequate provisions for large loads and directed the operator and its transmission owners either to defend the status quo or to propose fixes.15 The original sixty-day clock would have put responses due August 17. Every region sought, and received, roughly ninety days of abeyance so it could run a stakeholder process and file under section 205 instead.36
Across the orders, operators were told to address application and study processes for transmission service on behalf of large loads; cost-shifting protections and upgrade transparency; co-location and behind-the-meter generation; new services for loads willing to limit withdrawals; and a way to study generating facilities that serve electrically proximate large loads.12 FERC also suggested that a large load of fifty megawatts or more at a single site, interconnecting above roughly sixty-nine kilovolts and not already in a co-location arrangement, was a reasonable starting definition.5
A working scorecard
None of the November packages is fully public yet. What is public are board memos, stakeholder summaries and, in PJM's case, a compliance matrix posted for the Members Committee. The table below treats those materials as proposals, not accepted tariffs.
| Region (docket) | Large-load threshold (proposed/accepted) | Study clock (as previewed) | Cost security / who pays upgrades | Interim or flexible service | Co-location / proximate generation |
|---|---|---|---|---|---|
| PJM (EL26-67) | 50 MW single-site definition already accepted Oct. 9 in ER26-3515; registry effective Oct. 127 | New study process targeting ≤60–90 days4 | Pro forma cost-recovery agreement left to transmission owners; financial security contemplated4 | Expanded interim NITS plus firm and non-firm contract demand services to be proposed Nov. 164 | Co-location largely handled in separate EL25-49 track; show-cause filing focused on non-co-located large loads24 |
| MISO (EL26-70) | 50 MW at a substation in Aug. reliability filing; LARS pairs ≥200 MW load with proximate generation8 | LARS: up to 120 days (filed Oct. 2)8 | Cost-recovery / anti-shifting package still expected Nov. 16; states have flagged the gap8 | Not the centerpiece of LARS; watch Nov. 16 for flexible-service language | LARS is itself a joint load–generation study with a proposed 15-year tie8 |
| CAISO (EL26-71) | End-use peak ≥50 MW at a POI on the ISO grid (board-approved)9 | PTOs: 60–90 days, with monthly ISO review of out-of-cycle upgrades9 | PTOs to write deposit/financing terms; ISO to post aggregate upgrades and cost estimates9 | Flexible Interim Load Interconnection (FILI) until upgrades finish; permanent flexible option deferred to 20279 | Onsite-only generation exempt from ISO study; injecting generation studied; co-located load metered independently for ancillary charges9 |
| ISO-NE (EL26-72) | Commercial/industrial ≥50 MW gross peak (proposal)10 | 90 days unless EMT or cluster work required; applications targeted June 1, 202710 | $50k application fee, $150k study deposit, $10k/MW readiness deposit (stakeholder materials)1011 | Firm, Interim and Non-Firm Contract Demand Service; interim up to 7 years or until upgrades/capacity arrive; $250/MWh redispatch trigger on non-firm10 | Non-firm generator arrangements for co-located / electrically proximate resources in the proposal package10 |
| NYISO (EL26-69) | Large-load track under development for Nov. 16 filing12 | Readiness deposits and withdrawal rules previewed in secondary reporting12 | Financial-reservation model already distinctive; show-cause asks for stronger study and cost clarity212 | Firm / non-firm / zero-withdrawal services reported in previews12 | Co-located aggregation treated separately rather than netted, per secondary summaries12 |
| SPP (EL26-68) | HILL already in tariff (10 MW ≤69 kV; 50 MW >69 kV)5 | HILL / HILLGA already accepted; Nov. 20 filing is completion, not invention25 | Pro forma cost-recovery agreement and posting still on the to-do list12 | CHILLS: interruptible service up to 7 years while firm supply and upgrades catch up5 | HILLGA already studies shovel-ready generation with the load5 |
Fifty megawatts and the study clock
The fifty-megawatt line is becoming the common language of the proceedings. PJM already has it in an accepted tariff definition; CAISO and ISO-NE are proposing the same peak. MISO's reliability filing uses fifty megawatts at a substation and then layers a higher two-hundred-megawatt gate for its joint study product.78910
Study timelines are where the regions diverge in ways a developer can price. FERC's orders pressed for sixty-to-ninety-day study clocks.2 CAISO is putting that obligation on participating transmission owners, with monthly ISO review of out-of-cycle upgrades.9 ISO-NE aims at ninety days for a serial study, with applications starting June 1, 2027.10 MISO's LARS runs up to one hundred twenty days but studies load and generation together.8 PJM's matrix commits to a sixty-to-ninety-day deadline inside a new study process that still has to be filed.4
A faster study is not a faster substation. It is an earlier answer. The upgrades identified still take years. What changes in November is how long a developer waits to learn which upgrades those are, and what service it can buy while it waits.
Cost security and stranded upgrades
The part of the orders that matters most to existing customers, and therefore to every state commission watching these dockets, is cost shifting. FERC asked for transparency into which network upgrades are built for which loads and for a pro forma cost-recovery agreement, backed by financial security, so that a load that shrinks, delays or disappears does not leave upgrade costs in everyone else's rate base.25
ISO-NE's materials are the most concrete on the front-end deposits: a fifty-thousand-dollar application fee, a one-hundred-fifty-thousand-dollar study deposit and a readiness deposit of ten thousand dollars per megawatt.1011 CAISO is pushing the financing and anti-shifting terms into transmission-owner tariffs while promising public posting of aggregate large-load additions, planned upgrades and cost estimates.9 PJM's matrix says the transmission owners, not PJM, are writing the cost-recovery agreement.4 MISO has already filed LARS and told stakeholders the cost-recovery package follows on November 16; state regulators and clean-energy intervenors have already told FERC they see that sequence as a problem.8
For a hyperscaler energy team, the question is practical. If the project is canceled after the study but before energization, who keeps the security, who pays for partially built upgrades, and how long does the obligation run if the load under-delivers?
Curtailable interim service as a speed-to-power trade
Every region now has, or is about to file, some version of early access in exchange for flexibility. The products are not interchangeable.
CAISO's Flexible Interim Load Interconnection lets a large load take service before its network upgrades are finished, with flexibility requirements set by local constraints and with remote disconnect available to the ISO when reliability requires it. When the upgrades are done, the load moves to firm interconnection. A permanent flexible product was deferred to a 2027 initiative.9
SPP already offers Conditional High Impact Large Load Service: non-firm, interruptible transfers for up to seven years while designated resources and upgrades are lined up. There is no tariff cap, in the materials reviewed for this article, on how often or how long curtailment can last.512
ISO-NE's menu is the most fully specified in stakeholder form. Firm Contract Demand Service requires completed upgrades and designated new capacity. Interim Contract Demand Service is temporary and non-firm, lasting up to seven years or until the upgrades and capacity arrive, whichever is longer. Non-Firm Contract Demand Service is permanent and is studied around the load's flexibility. While on interim or non-firm service, the proposal would redispatch the load when its locational price exceeds two hundred fifty dollars per megawatt-hour.10
PJM's October 9 order in a different docket, ER26-3515, is the cautionary backdrop rather than the November filing itself. FERC kept PJM's large-load registry and fifty-megawatt definition but rejected the Interim Resource Adequacy Service that would have made curtailment the default for uncovered new load, finding that the filed tariff appeared to place retail obligations on end-use customers.7 PJM's show-cause matrix now points instead to voluntary firm and non-firm contract demand services and an expanded interim network product.4 A voluntary non-firm election is a different jurisdictional animal from an involuntary curtailment backstop written onto retail customers.
What to ask for in the comment window
The thirty-day answer period is short. A developer or load-serving entity that wants the record to reflect commercial reality should read each filing against a short list of questions rather than against a wish for uniform national rules.
Does the study clock start when the application is complete, and what happens if the operator needs an electromagnetic-transient study or a cluster restudy? Are readiness deposits refundable, and on what milestones? Does the cost-recovery agreement survive cancellation, partial energization and early exit, and is the security sized to the upgrades actually triggered? For interim service, is curtailment or redispatch voluntary, how is it sequenced against existing demand response, and is there a path and a deadline to convert to firm service? For co-location, is the load metered gross for ancillary services, and can proximate generation be studied with the load without waiting in the ordinary generation queue?
PJM's separate October ruling already showed that FERC will accept a registry and reject a curtailment design that crosses into retail authority. The November filings will be judged on the same instincts: clarity for investors, protection for existing transmission customers, and respect for the line between wholesale transmission service and state retail regulation. The scorecard is a reading guide for the week the answers arrive, not a prediction of which tariff FERC will keep.
Notes
- Federal Energy Regulatory Commission, "FERC Launches Aggressive Targeted Action to Speed Large Load Integration," news release, June 18, 2026, https://www.ferc.gov/news-events/news/ferc-launches-aggressive-targeted-action-speed-large-load-integration.↩︎
- Day Pitney LLP, "FERC Issues Show Cause Orders to Six RTOs/ISOs on Large Load Integration," June 23, 2026, https://www.daypitney.com/ferc-issues-show-cause-orders-to-six-rtos/isos-on-large-load-integration (citing 195 FERC ¶¶ 61,211–61,216 and dockets EL26-67 through EL26-72).↩︎
- Federal Energy Regulatory Commission, PJM Interconnection, L.L.C., 196 FERC ¶ 61,129, Docket No. EL26-67-000 (August 14, 2026) (abeyance; responses due November 16, 2026; answers due December 16, 2026); California ISO, "Regulatory Report – Oct 2026," noting the same November 16 / December 16 calendar for EL26-71.↩︎
- PJM Interconnection, "PJM's Response Matrix to the Large Load Show Cause Order Opportunities," prepared for public posting October 29, 2026, Members Committee special session, November 5, 2026, https://www.pjm.com/-/media/DotCom/committees-groups/committees/mc/2026/20261105-special/item-01---2-large-load-compliance-matrix.pdf.↩︎
- Federal Energy Regulatory Commission, ISO New England Inc., 195 FERC ¶ 61,215, Docket No. EL26-72-000 (June 18, 2026), including the suggested large-load definition and discussion of SPP's HILL, HILLGA and CHILLS orders; PDF at https://www.ferc.gov/sites/default/files/2026-06/EL26-72-000..pdf.↩︎
- Marin Holt, "All Six Grid Operators Ask FERC for 90 More Days on Large-Load Rules, Pushing Filings to November 16," mgrid.org, August 13, 2026, https://mgrid.org/2026/08/13/all-six-grid-operators-ask-ferc-for-90-more-days-on-large-load-rules-pushing-filings-to-november-16/.↩︎
- Federal Energy Regulatory Commission, PJM Interconnection, L.L.C., 197 FERC ¶ 61,019, Docket No. ER26-3515-000 (October 9, 2026) (accepting Large Load definition and registry; rejecting IRAS and related capacity constructs). See also AIxEnergy, "Bring Your Own Capacity, Take Two: What PJM's November 16 Refiling Has to Fix" (draft), for the ER26-3515 analysis; this article does not repeat that docket.↩︎
- Utility Dive reporting on MISO's October 2, 2026 LARS filing (120-day joint study for loads above 200 MW with proximate generation) and subsequent protests raising cost-shifting concerns; MISO has stated cost-recovery terms follow in the November 16 show-cause response.↩︎
- Neil Millar, "Response to FERC Large Loads Order to Show Cause," memorandum to the ISO Board of Governors, October 22, 2026, https://www.caiso.com/documents/decision-on-large-load-enhancements-memo-oct-2026.pdf; Elena Park, "CAISO Board Approves 50-MW Large-Load Framework With a Flexible Interim Service," Data Center Feed, November 1, 2026, https://datacenterfeed.com/article/caiso-board-approves-50-mw-large-load-framework-ferc-filing-november-2026.↩︎
- ISO New England, "Large Loads Integration Proposal Information," summary dated October 9, 2026, https://www.iso-ne.com/static-assets/documents/100040/large_loads_integration_proposal_information_summary_10.09.26.pdf (50 MW threshold; FCDS/ICDS/NFCDS; 90-day study; $10,000/MW readiness deposit; $250/MWh Non-Firm Large Load Re-Dispatch Price; June 1, 2027 process start).↩︎
- ISO-NE Transmission Committee materials (September–October 2026) describing a $50,000 non-refundable application fee and $150,000 study deposit, as summarized in contemporaneous reporting of those slides.↩︎
- Mara Ellison, "Six Answers Due in Two Weeks: What FERC's Large-Load Show-Cause Filings Will Decide," Fracmoo, November 2, 2026, https://fracmoo.com/electric-grid/ferc-show-cause-responses-november-deadline/ (used for SPP November 20 calendar and NYISO preview detail not yet confirmed in a retrieved primary PDF; treat as secondary).↩︎
Bibliography
- Day Pitney LLP. "FERC Issues Show Cause Orders to Six RTOs/ISOs on Large Load Integration." June 23, 2026. https://www.daypitney.com/ferc-issues-show-cause-orders-to-six-rtos/isos-on-large-load-integration.
- Ellison, Mara. "Six Answers Due in Two Weeks: What FERC's Large-Load Show-Cause Filings Will Decide." Fracmoo, November 2, 2026. https://fracmoo.com/electric-grid/ferc-show-cause-responses-november-deadline/.
- Federal Energy Regulatory Commission. "FERC Launches Aggressive Targeted Action to Speed Large Load Integration." News release, June 18, 2026. https://www.ferc.gov/news-events/news/ferc-launches-aggressive-targeted-action-speed-large-load-integration.
- Federal Energy Regulatory Commission. ISO New England Inc., 195 FERC ¶ 61,215. Docket No. EL26-72-000. June 18, 2026. https://www.ferc.gov/sites/default/files/2026-06/EL26-72-000..pdf.
- Federal Energy Regulatory Commission. PJM Interconnection, L.L.C., 196 FERC ¶ 61,129. Docket No. EL26-67-000. August 14, 2026. https://www.pjm.com/-/media/DotCom/documents/ferc/orders/2026/20260814-el26-67-000.pdf.
- Federal Energy Regulatory Commission. PJM Interconnection, L.L.C., 197 FERC ¶ 61,019. Docket No. ER26-3515-000. October 9, 2026.
- Holt, Marin. "All Six Grid Operators Ask FERC for 90 More Days on Large-Load Rules, Pushing Filings to November 16." mgrid.org, August 13, 2026. https://mgrid.org/2026/08/13/all-six-grid-operators-ask-ferc-for-90-more-days-on-large-load-rules-pushing-filings-to-november-16/.
- ISO New England. "Large Loads Integration Proposal Information." October 9, 2026. https://www.iso-ne.com/static-assets/documents/100040/large_loads_integration_proposal_information_summary_10.09.26.pdf.
- Millar, Neil. "Response to FERC Large Loads Order to Show Cause." Memorandum to the ISO Board of Governors, October 22, 2026. https://www.caiso.com/documents/decision-on-large-load-enhancements-memo-oct-2026.pdf.
- Park, Elena. "CAISO Board Approves 50-MW Large-Load Framework With a Flexible Interim Service, With Tariff Filing Due at FERC Nov. 16." Data Center Feed, November 1, 2026. https://datacenterfeed.com/article/caiso-board-approves-50-mw-large-load-framework-ferc-filing-november-2026.
- PJM Interconnection. "PJM's Response Matrix to the Large Load Show Cause Order Opportunities." Members Committee special session, November 5, 2026. https://www.pjm.com/-/media/DotCom/committees-groups/committees/mc/2026/20261105-special/item-01---2-large-load-compliance-matrix.pdf.
