ERCOT's 91,308 MW Peak and 2027 4CP Transmission Charges for Texas Grows

The July 22, 2026 peak

Texas media reported ERCOT load reached a preliminary 91,308 MW around 5 p.m. Central on July 22, 2026, during a statewide heat wave [express-news-ercot-2026]. ERCOT's official peak demand records page lists the settled July 22, 2026 record at 91,089 MW, surpassing the prior record of 85,508 MW on August 10, 2023 [ercot-all-time-peaks].

The Texas Tribune noted the grid still held roughly 20,000 MW of reserve margin at the peak hour, with solar supplying more than 45% of generation at times and battery discharge setting records near 11,980 MW [texas-tribune-ercot-2026].

Reliability held. 4CP accounting still captured the interval for 2027 transmission bills.

How 4CP transmission charges work

Under PUC rules, ERCOT identifies the four highest system load intervals each year during June through September, typically weekday afternoon hours [tx-4cp-mechanics]. Each commercial customer's demand during those intervals determines their share of transmission cost allocation the following calendar year.

This is separate from:

Retail energy kWh charges (shoppable in competitive areas).

TDSP distribution demand charges on some tariffs.

Capacity mechanisms in ERCOT's ORDC/scarcity design.

4CP is why Texas operators watch 3-6 p.m. all summer, not only bill peak.

Why cannabis loads care

Indoor cultivation often sets facility peak when lights energize, frequently overlapping afternoon grid peak in summer when HVAC load is highest. A 600 kW grow that hits 600 kW during a 4CP interval carries 600 kW into the transmission allocation formula for 2027 [tx-4cp-mechanics].

Staggering flower rooms so not all rooms light at 2 p.m. during June through September can drop 4CP contribution without reducing total kWh. See peak demand vs peak usage.

Texas low-THC program expansions add new facilities that may underestimate 4CP on first-year pro formas [texas-tribune-ercot-2026].

July 22 as a locked 4CP candidate

Texas Commercial Plans analysis noted July 22, 2026 likely remains in the final four even if September posts a higher peak, because it exceeded prior July 4CP candidates by a wide margin [tx-4cp-mechanics].

If your interval data shows a spike on July 22 near 5 p.m., assume that hour is baked into 2027 transmission allocation unless later peaks exceed it.

Reading July 22 interval data against ERCOT's 4CP clock

ERCOT posts integrated hourly system demand for peak records; July 22, 2026 settled at 91,089 MW as the official hourly record [ercot-all-time-peaks]. Preliminary real-time operations showed 91,308 MW around 5 p.m. [express-news-ercot-2026]. Four Coincident Peak selection uses the four highest system intervals June through September, then allocates transmission based on your meter demand in those intervals [tx-4cp-mechanics].

Your TDSP records 15-minute demand. The 4CP interval may be the hour ending 5 p.m. Central even if your facility peaked in a different 15-minute block inside that hour.

Illustrative July 22 meter read for a Round Rock cultivation site:

Interval (CDT)	Facility kW	System event
4:15–4:30 p.m.	540	Ramp before full light
4:30–4:45 p.m.	620	All flower rooms on
4:45–5:00 p.m.	610	HVAC catch-up
Hour average used for 4CP	~623	Likely 4CP candidate hour [tx-4cp-mechanics]

If September produces a higher system peak but your facility ran maintenance that day at 400 kW, September may enter the 4CP set while your contribution stays low for that interval. Your allocation averages demand across the four system peaks, not your four highest hours.

At $4.50/kW-month transmission (prior illustrative rate), dropping hour-average contribution from 623 kW to 543 kW across all four peaks saves 80 kW × $4.50 × 12 ≈ $4,320/year. Document schedule changes so finance can tie savings to intentional curtailment. Texas Tribune reported solar above 45% of generation and battery discharge near 11,980 MW at the July peak [texas-tribune-ercot-2026], which kept energy prices manageable even as transmission allocation captured the interval.

Worked transmission impact (illustrative)

Assume:

Your 4CP average demand during the four system peaks: 520 kW

Transmission rate after allocation: $4.50/kW-month (illustrative TDSP tariff input)

Line	Calculation	Annual
Monthly transmission	520 × $4.50	$2,340
Annual	× 12	$28,080

Cutting 4CP contribution by 80 kW through scheduling saves about $4,320/year at the same illustrative rate. Actual TDSP tariffs and rider updates vary; pull your TDSP's current transmission cost recovery factor.

PUCT move from 4CP to 12CP

Stakeholder discussions propose shifting from four peaks to twelve coincident peaks by December 31, 2026 [energyby5-12cp]. More intervals could:

Reduce lottery risk of one bad hour dominating allocation.

Require sustained peak management across more summer afternoons.

Change ROI on automation that shifts vege lighting loads.

Monitor PUCT filings if your pro forma assumes classic 4CP through 2027.

ERCOT growth context

ERCOT CEO Pablo Vegas told lawmakers demand could reach roughly 175,000 MW within six years, driven by data centers and population growth [texas-tribune-ercot-2026]. Record peaks will recur. Transmission expansion costs flow partly through 4CP allocation.

Cannabis is not driving the headline forecast, but every new grow adds afternoon load in competitive retail zones.

Actions for Texas operators rest of summer 2026

Download interval data from your TDSP portal weekly through September.

Track ERCOT system load forecasts on peak days; curtail nonessential load 2-6 p.m.

Avoid maintenance tests that energize all rooms simultaneously during heat events.

Compare Texas commercial supply quotes separately from transmission; a cheap energy rate does not fix 4CP.

Document light schedules if you stagger; prove intentional peak reduction to ownership.

Winter note

4CP uses June through September only. Winter peaks matter for energy pricing on index contracts but not this specific transmission allocator. Texas operators still separate seasons in budgeting.

ERCOT's record July 2026 peak proved the grid could serve load [express-news-ercot-2026]. Your 2027 job is ensuring your meter was not at its maximum during the wrong four hours.

TDSP differences: Oncor, CenterPoint, and AEP Texas

Four Coincident Peak allocation uses ERCOT system peaks, but transmission cost recovery factors differ by TDSP [tx-4cp-mechanics]. A 500 kW 4CP average contribution hits your bill through your TDSP's tariff riders, not through your retail energy supplier [tx-4cp-mechanics].

Shopping a cheap ¢/kWh energy contract in Oncor territory does not change 4CP math if your meter still peaks during system coincident hours [express-news-ercot-2026]. Texas Tribune reported solar above 45% of generation and battery discharge near 11,980 MW at the July 22 peak [texas-tribune-ercot-2026]. Energy prices stayed manageable while transmission allocation still captured the interval for 2027 bills [tx-4cp-mechanics].

Automation that shifts vege room light start from 2 p.m. to 8 p.m. June through September reduces the odds all flower rooms align with a 4CP candidate hour [tx-4cp-mechanics]. Document schedule changes so ownership can tie lower 2027 transmission lines to intentional operations, not luck.

PUCT discussions propose moving from four peaks to twelve coincident peaks by December 31, 2026 [energyby5-12cp]. If adopted, sustained afternoon management across more days could matter more than avoiding one bad hour [energyby5-12cp]. ERCOT CEO Pablo Vegas told lawmakers demand could reach roughly 175,000 MW within six years [texas-tribune-ercot-2026]. Transmission expansion costs will keep flowing through allocation mechanics cultivators cannot shop away [ercot-all-time-peaks].

Pull weekly interval exports from your TDSP portal through September 30. Mark hours when ERCOT publishes system load above 88,000 MW and compare to your facility kW. That overlay tells you whether 2027 transmission is already locked or still in play [ercot-all-time-peaks] [tx-4cp-mechanics].

Energy rate vs transmission: separate shops, separate peaks

San Antonio Express-News reported preliminary load near 91,308 MW around 5 p.m. Central on July 22, 2026, during a statewide heat wave [express-news-ercot-2026]. ERCOT's settled hourly record lists 91,089 MW for that date [ercot-all-time-peaks]. Retail energy prices can stay moderate when solar and batteries cover a large share of generation, as The Texas Tribune reported for the same event [texas-tribune-ercot-2026]. 4CP transmission still records your meter demand during system peak intervals regardless of energy rate [tx-4cp-mechanics].

Texas operators routinely shop energy at 4 to 6 ¢/kWh while paying transmission allocated from four summer afternoons [tx-4cp-mechanics]. A cultivation CFO should budget two workflows: procurement for kWh, and operations for kW June through September [ercot-all-time-peaks]. Switching retail providers does not reset 4CP history on the TDSP meter [express-news-ercot-2026].

If PUCT moves to twelve coincident peaks, the same separation applies with more afternoons in scope [energyby5-12cp]. Automation that staggers vege lighting becomes a transmission strategy, not an energy shopping strategy [energyby5-12cp] [tx-4cp-mechanics].

Texas Commercial Plans analysis noted July 22, 2026 likely remains in the final four even if September posts a higher peak, because it exceeded prior July candidates by a wide margin [tx-4cp-mechanics]. If your interval log shows full lighting load during that hour, treat 2027 transmission as largely set and focus September on avoiding a second spike that could replace a milder interval in the set of four [ercot-all-time-peaks] [tx-4cp-mechanics]. Winter peaks affect index energy but not this June through September allocator [ercot-all-time-peaks]. Compare Texas commercial supply quotes separately from transmission; a lower energy rate does not fix 4CP contribution [tx-4cp-mechanics] [express-news-ercot-2026].