Texas Regulators Would Replace ERCOT’s Four Summer Peaks With Twelve Monthly Ones

One kilowatt of demand during each of ERCOT’s four summer coincident peaks costs a Texas commercial customer roughly $68.55 over the following year. A facility that holds one megawatt off the grid across all four intervals avoids about $68,550.

The Public Utility Commission of Texas has proposed to stop measuring those four intervals.

Staff published the proposed rule in Project 58000 in the Texas Register on July 24, 2026, following a proposal for publication adopted on July 9. The comment period closed on August 11.

The count goes from four to twelve. The current method takes the single highest 15-minute system interval in each of June, July, August and September. The proposed method takes one coincident peak in every calendar month, measured across 30 minutes, on a measurement year running October 1 through September 30.

The threshold is 700 kilowatts. Facilities exceeding roughly 700 kW of peak demand in Oncor, CenterPoint, AEP Texas and TNMP territory carry the 4CP exposure that the rulemaking would restructure. The proposal governs how wholesale transmission cost is allocated across that population.

The statute set the clock. Senate Bill 6 requires the commission to amend the rule by December 31, 2026. The deadline applies to the rule text. It is a deadline to finish writing a methodology, not a date on which billing determinants under that methodology begin accumulating, and the public record of the rulemaking does not fix the latter. What exists today is a proposed rule, a closed comment period, and a statutory deadline.

That distinction matters for anyone reading the October 1 start of the measurement year as a date that has already begun governing Texas electricity bills. The measurement year is a feature of the proposed methodology. Whether the first cycle under it is the one now running, or one that starts in 2027 or later, is an implementation question the published record leaves open.

Large loads would carry a minimum billing demand. The same rulemaking would require large load customers to pay a minimum demand charge based on contracted peak demand, with billing starting when service becomes available. K&L Gates, summarizing the draft report, described the obligation as running 10 to 15 years. The commission has separately requested comment on whether the term should instead run a fixed 20 years, phase down across 20 years, or use a ratcheted mechanism with declining percentages. The provision is scoped to large load customers, which leaves ordinary commercial buildings outside it.

Thirty minutes doubles the energy requirement. What follows is interpretation rather than reporting. A battery discharging to cover a 15-minute settlement interval at one megawatt needs 250 kWh of deliverable energy. The same megawatt across a 30-minute interval needs 500 kWh. Lengthening the measurement window is the provision most directly aimed at short-duration response, and it changes the sizing math for every asset bought to shave a Texas transmission peak, whether that asset is a battery, a generator, or a curtailment agreement with a tenant.

The count of events compounds the same effect. A dispatcher does not discharge four times a year under 4CP, because the settling interval is known only after the fact. A dispatcher discharges on every candidate afternoon inside a forecast band. Under twelve monthly peaks, candidate intervals appear in months that currently generate none, including winter hours when onsite solar contributes nothing and a facilities team has the least tolerance for manual load shedding in an occupied building.

Four summer afternoons can be managed with a calendar, a weather feed, and a willingness to inconvenience people in July. Twelve monthly windows, measured over twice the duration and spread across all four seasons, sit outside what manual intervention reliably delivers. The asset class that answers a twelve-peak structure is automated and always available, which is a different procurement decision from the one a Texas facilities manager has been making for the past decade.

The seasonal spread is the part with the longest reach. Four summer intervals measure a grid under air-conditioning load. Twelve monthly intervals measure it in December and January as well, when ERCOT’s own stress profile looks nothing like an August afternoon. A cost allocation method that samples the whole year assigns cost on a different basis than one that samples a single season, and buildings whose load shape is flat across the year will fare differently from buildings whose load is summer-weighted.

None of that becomes real until the commission issues a final order. The substance of the rulemaking is on the public record and the deadline to complete it is fixed. The question of when the resulting billing determinants start accumulating is not answered there. Two separate decisions are in play: the rule text specifies how the peaks are counted, and a separate implementation decision specifies when the counting starts. Only the first currently has a date attached to it.

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