$329.17/MW-day PJM Capacity Started Hitting Bills June 1, 2026

Where $329.17 per MW-day comes from

PJM's 2026/27 Base Residual Auction cleared the entire RTO at the FERC-approved price cap of $120,147 per MW-year [enel-pjm-2026-27-auction]. Divide by 365 days and you get $329.17 per MW-day. That is the number suppliers reference when explaining the June 1, 2026 step change on invoices.

The prior delivery year cleared at $269.92 per MW-day ($98,521 per MW-year) [enel-pjm-2026-27-auction]. The 2026/27 cap is about 22 percent higher than the already record-breaking 2025/26 year. Enel noted a simulation without the cap would have cleared near $388 per MW-day [enel-pjm-2026-27-auction], meaning the collar limited but did not eliminate the increase.

What changed June 1, 2026

PJM capacity delivery years run June 1 through May 31. On June 1, 2026, supply rates tied to the 2026/27 RPM result replaced the 2025/26 capacity charge. If you were on ComEd's default supply, CUB reported the summer price to compare at 10.399 cents per kWh for June through September 2026, up sharply from prior years partly because of PJM capacity in the stack [cub-comed-summer-2026].

Third-party supply contracts behave differently depending on fine print. A fully fixed contract may have absorbed the increase until renewal. A contract with RPM pass-through showed the step immediately. An index contract floats with market components daily but still settles capacity monthly or quarterly per the supplier schedule.

Converting capacity to cents per kWh for a grow

Capacity cost depends on your load factor, not just your peak kW. The formula:

Annual capacity cost ≈ (peak load contribution in MW) × ($120,147/MW-year)

Effective capacity adder ≈ annual capacity cost ÷ annual kWh

Assume a 12,000 sq ft indoor flower facility with 600 kW peak demand and 2.4 million kWh annual use (a flat, lights-on-heavy profile).

Input	Value
Peak load contribution	0.6 MW
RPM clearing price	$120,147/MW-year [enel-pjm-2026-27-auction]
Annual capacity cost	$72,088
Annual kWh	2,400,000
Capacity-only adder	3.0 ¢/kWh

That 3 cents is capacity alone, before energy, losses, ancillaries, and supplier margin. A facility with the same peak but lower annual kWh (worse load factor) sees a higher effective adder. A facility that cuts peak without cutting energy may pay nearly the same capacity on a ratcheted delivery tariff while saving less on supply capacity if PLC is set by peak hours.

Why cultivators feel this more than office buildings

Cannabis cultivation runs long hours at high demand. Demand charges already punish coincident lighting and HVAC peaks on the delivery side. On the supply side, low load factor means each kWh carries more fixed capacity dollars.

Enel reported 100 percent of offered demand response cleared in the 2026/27 auction, about 8 GW total [enel-pjm-2026-27-auction]. DR revenue can offset part of the capacity line for participants, but enrollment for the delivery year closes at auction. If you missed the 2026/27 window, your options are contract structure and peak management for the next auction cycle.

Zone differences inside PJM

The 2026/27 auction cleared at a single RTO-wide cap [enel-pjm-2026-27-auction]. Earlier years split prices across local deliverability areas, with BGE and Dominion zones spiking above the RTO average. For 2026/27, a Chicago grow and a Philadelphia grow reference the same $120,147/MW-year clearing price, though utility default bundles and supplier margins still differ by state.

Check your bill's zone label (ComEd, PECO, BGE, etc.) when comparing to a neighbor in another state. Delivery charges and state taxes diverge even when RPM clears uniformly.

How Peak Load Contribution differs from your meter peak

PJM capacity billing uses Peak Load Contribution (PLC), not your highest random 15-minute interval. Your supplier assigns PLC from your utility's coincident peak hours during the prior delivery year. ComEd and PECO publish which hours count toward network peak. Missing those hours means you can cut facility demand all year and still carry last summer's PLC on your RPM invoice.

Suppose your meter peaked at 650 kW on a mild October morning when only HVAC ran, but PJM's five coincident peak hours last June through September hit 580 kW because you staggered flower rooms. Your PLC for capacity may track closer to 580 kW than 650 kW depending on how the utility assigns unaccounted-for load and whether your supplier uses PLC or internal peak estimates.

Worked example for supply capacity only:

Input	Value
Assigned PLC	0.58 MW
2026/27 RPM rate	$120,147/MW-year [enel-pjm-2026-27-auction]
Annual capacity	$69,685
Annual kWh	2,400,000
Effective adder	2.9 ¢/kWh

If PLC stayed at 0.65 MW because peaks aligned with PJM coincidence, capacity rises to $78,096 or 3.3 ¢/kWh. That 0.4 ¢/kWh gap is $9,600 per year at this load. Staggering matters most when it moves PLC, not only when it trims a random afternoon spike.

Pull your supplier's PLC disclosure on the June invoice. Compare it to your utility's published coincident peak calendar. If they diverge, ask which value RPM uses before you renew for 2027/28.

Contract actions for the rest of 2026/27

Pull May and June supply invoices side by side. Identify the capacity or RPM line. If your supplier cannot explain it, that is a data problem you should fix before renewal.

Ask whether your fixed rate includes capacity through May 31, 2027. If capacity is pass-through, model exposure using your PLC and $329.17 per MW-day.

Do not wait until November to shop. Winter index prices can move, but RPM for this delivery year is already set. The decision is fixed versus pass-through structure, not guessing the auction again.

Coordinate with delivery demand work. Staggering flower rooms cuts utility demand charges. It may also lower peak load contribution if your PLC is set during coincident peak hours. Review your utility's PLC assignment rules with your supplier.

Looking ahead to June 2027

The 2027/28 auction ran in December 2025 with its own capped clearing price effective June 1, 2027 [pjm-2026-27-bra]. When renewing supply this winter, specify which delivery year's capacity your quote includes. Mixing a 24-month energy fix with one-year capacity pass-through is a common way operators thought they were hedged and were not.

For fixed versus index contracts, the cultivator question is not only "lock or float energy" but "who bears RPM for each June through May period." The $329.17/MW-day figure is the 2026/27 answer. Your contract language determines whether you pay it directly or through a bundled rate.

Reading capacity on a real supplier invoice layout

Suppliers label RPM pass-through differently. Common line names include "Capacity," "UCAP," "PJM RPM," or "RTO capacity." Some utilities bury capacity inside a default energy charge; third-party contracts often break it out monthly [enel-pjm-2026-27-auction] [cub-comed-summer-2026].

Walk through a June 2026 invoice reconciliation for a 500 kW PLC facility with 2.0 million annual kWh:

Step	What to pull	Why it matters
1	PLC or UCAP assignment in MW	Drives dollar obligation [enel-pjm-2026-27-auction]
2	$/MW-day or $/MW-year rate	Should trace to $329.17/MW-day for 2026/27 [enel-pjm-2026-27-auction]
3	Billing period days	Partial months prorate
4	Total kWh in same period	Converts fixed dollars to effective ¢/kWh
5	Prior May invoice	Isolates step change at June 1 [cub-comed-summer-2026]

If PLC is 0.52 MW and the supplier bills $329.17/MW-day for 30 days: 0.52 × $329.17 × 30 ≈ $5,135 capacity-only for that month before margin. At 170,000 kWh in June, that month carries about 3.0 ¢/kWh from capacity alone. Summer kWh are often higher than average, which lowers the effective adder if capacity is flat monthly. Winter months with lower kWh but the same PLC raise the effective ¢/kWh. That is why cultivators with bad load factor feel RPM harder than warehouses running one shift.

ComEd default supply customers saw the capacity step inside the summer price to compare CUB published at 10.399 ¢/kWh for June through September 2026 [cub-comed-summer-2026]. Shopping customers should not compare that headline to a supplier energy quote unless both include the same capacity treatment. A supplier offering 8.5 ¢/kWh energy with pass-through RPM may land above default once capacity is added.

Document PLC disputes early. If your supplier uses a PLC higher than your utility's published coincident peak contribution, ask for the calculation worksheet before you renew for 2027/28 [pjm-2026-27-bra].

BGE and Dominion: same RTO cap, different delivery stacks

The 2026/27 auction cleared at a single RTO-wide cap of $120,147/MW-year [enel-pjm-2026-27-auction]. Baltimore and Virginia cultivators reference the same RPM figure as ComEd customers even though delivery tariffs and state taxes diverge [enel-pjm-2026-27-auction]. A 450 kW PLC in BGE territory carries the same annual capacity obligation math as Chicago: 0.45 × $120,147 ≈ $54,066 before supplier margin [enel-pjm-2026-27-auction].

Where mid-Atlantic operators feel pain differently is load factor. A Pennsylvania flower facility with 2.2 million kWh at 450 kW PLC sees about 2.5 ¢/kWh capacity adder. A Maryland site with identical PLC but 1.9 million kWh because of shorter veg cycles sees about 2.8 ¢/kWh. Same auction, different effective rate because kWh denominators change [enel-pjm-2026-27-auction].

Enel reported a simulation without the price cap would have cleared near $388/MW-day [enel-pjm-2026-27-auction]. That counterfactual matters for 2027/28 renewals: if future auctions continue hitting caps, suppliers may keep pass-through language wide even when headline energy rates look competitive [pjm-2026-27-bra].