Dynawatt — June 29, 2026
The weekly read on AI and data-center load growth and the US grid.
This week the signal sits in two places. PJM is writing the rulebook for how data centers connect to the largest grid in the country, and the NRC cleared a major safety gate for the first US small modular reactor at scale. Both point the same way. Load is showing up faster than firm supply, and the institutions are improvising in real time.
Large load & data centers
PJM moves toward “Connect and Manage” for large loads
PJM’s Board has directed a framework that would let large loads, data centers chief among them, connect to the transmission system before the upgrades that normally support them are finished. The trade is explicit. A load that does not bring its own new generation (PJM’s “Bring Your Own New Generation,” or BYONG, test) accepts non-firm status and agrees to be curtailed during system stress, ahead of pre-emergency demand response. It began as an Exelon problem statement at the Markets and Reliability Committee in February. It’s now a Board-directed workstream under a new Senior Task Force, with tariff and operational language targeted for the back half of 2026.
The moving parts worth tracking:
Loads connecting under the framework would sit outside the capacity market’s Base Residual Auction. That’s PJM’s mechanism for keeping the cost off everyone else.
A proposed Large Load Registry (50 MW and up per delivery point) would give states and utilities real-time visibility into where demand is landing, shifting enforcement toward state retail regulators instead of PJM mandates.
A separate EDC and data-center coalition proposal floats a subscription-style backstop procurement, with a price cap near $555/MW-day and a 500 MW locational limit, deferring existing tariff backstops to the 2030/31 delivery year.
The Data Center Coalition is pushing a state opt-in version: interruptible service classes, plus manual load-shed that curtails large commercial and industrial before residential.
The through-line is that nobody disputes the loads are coming. The fight is over who gets curtailed first, who pays, and whether the state or the RTO holds the lever.
ISO: PJM · Type: large-load · Stage: rule-change · Parties: Exelon, Data Center Coalition
Why PJM is in a hurry
PJM’s February long-term forecast raised the 20-year summer growth rate from 2.0% to 2.4%, with an explicit data-center adjustment across 13 member utilities and roughly 18.6 GW of net increase penciled in by 2040. Near-term numbers actually came down. The back half of the curve jumped. Meanwhile the 2027/2028 capacity auction cleared about 6.5 GW short of the reserve-margin target, driven by new large-load submissions with no matching supply. That gap is the entire reason Connect and Manage exists.
ISO: PJM · Type: large-load · Stage: study · Capacity: 18.6 GW
Nuclear & firm power
Clinch River clears its safety review
The NRC issued the Final Safety Evaluation Report for TVA’s Clinch River Unit 1 construction permit (Docket 50-615) in June. For the GE Hitachi BWRX-300, this is the gate that matters. The FSER means the agency has finished its technical review, and it lands alongside an ACRS safety report and a Revision 1 PSAR filing. Clinch River is the closest thing the US has to a flagship SMR, and it just moved materially closer to a construction authorization.
Type: nuclear · Stage: cod · State: TN · Parties: TVA, GE Hitachi
Palisades, twice over
Two different things are happening at the Palisades site in Michigan, and they’re easy to confuse. The existing 800 MW reactor (Entergy) is being restarted with DOE backing. The Energy Dominance Financing program approved its fourth, fifth, and sixth loan disbursements this period, a steady drip that reads as federal commitment to getting baseload back online. Separately, Holtec’s Palisades SMR LLC has filed a phased construction permit for two SMR-300 units (Pioneer 1 and 2), and the NRC has opened EIS scoping plus Section 106 cultural consultations with more than a dozen tribes. The consultation volume is procedural. Read it as the EIS clock starting, not as a dozen separate milestones.
Type: nuclear · Stage: study + cod · Capacity: 800 MW + 2×300 MW · State: MI · Parties: Entergy, Holtec
The advanced-reactor pipeline keeps filling
Oklo got preliminary NRC feedback on moving Aurora from DOE authorization to full NRC licensing, completed a pre-Phase 2 audit on its combined license application, and filed approved principal design criteria. X-energy cleared a graphite core verification for the Xe-100. None of these are construction events. They’re the licensing queue stacking up, which is the leading indicator for the firm power data-center developers actually want.
Type: nuclear · Stage: study · Parties: Oklo, X-energy
DOE keeps writing checks
Beyond Palisades, the Loan Programs Office closed a guarantee to restart a Pennsylvania reactor, backed a nuclear supply-chain financing portfolio, and reaffirmed support for the Vogtle expansion (~2.2 GW) through conditional commitment and financial close. The NRC also filed its May status report under Executive Order 14156, the national energy emergency declaration that sits over most of this activity.
Type: nuclear · Stage: cod + rule-change · Parties: DOE LPO, Southern Company
Storage & interconnection
CAISO logged three grid-scale batteries. Plano Storage (350 MW, Monterey County) reached commercial operation. Bateria del Sur (350 MW, Imperial County) and Dallas Energy Storage (400 MW, Monterey County) entered the queue. Storage stays the steadiest line in CAISO’s pipeline, the fast-response capacity the grid leans on while firmer resources grind through longer queues.
ISO: CAISO · Type: storage · State: CA
The week in one line. Demand is now the thing the system plans around. PJM is drafting rules to curtail it, the NRC is licensing the reactors meant to feed it, and DOE is financing the restarts in between.
Dynawatt is an independent brief compiled from public sources: ISO/RTO interconnection queues, FERC notices (Federal Register), the ERCOT Large Load Working Group, PJM stakeholder committees, NRC ADAMS, and DOE Loan Programs Office announcements. Informational, non-advocacy, not investment advice.