The 4CP successor
ERCOT 12CP, explained
Texas is rewriting how transmission costs get allocated. The PUCT must adopt a final rule by December 31, 2026 — and the leading candidate direction replaces the four summer coincident peaks with a monthly-peak methodology. Everything you built around June–September afternoons is about to meet January mornings.
What is ERCOT 12CP?
12CP is a transmission cost allocation methodology that uses the highest system-demand interval of every month — twelve coincident peaks a year — instead of ERCOT's current four summer peaks (4CP). Your transmission charges would follow your average share of system load across all twelve intervals.
Is 12CP final?
No. The PUCT is conducting a rulemaking on transmission cost allocation and is required to adopt a final rule by December 31, 2026. The exact methodology — pure 12CP, a hybrid, or something else — is what the rulemaking will decide. This page tracks the docket.
How would 12CP change peak-chasing?
Under 4CP, response concentrates on hot summer afternoons. Under 12CP, every month has a peak that matters — including winter mornings, when Texas peaks during cold snaps. Curtailment strategies, battery schedules, and alert calendars all need to spread across the year, at roughly one-third the per-interval stakes.
When should I start planning?
Before the rule is final. The first year under a new methodology rewards whoever modeled it earliest — the data to estimate your exposure under a 12CP-style allocation already exists in your interval meter history. WattMarkets ships a 12CP preview program so you can watch both scoreboards at once.
Rule tracker
updated with each docket event- 2025Legislature directs the PUCT to review wholesale transmission cost allocation; rulemaking project opened.
- 2026 H1Comment cycles under way. Positions split along familiar lines: large industrials defend 4CP; utilities and consumer groups push broader allocation.
- Dec 31, 2026Statutory deadline for the final rule. WattMarkets ships the final-rule program config the week it lands.
See your 12CP exposure before the rules land
The ERCOT 12CP · 2027 (draft preview) program runs inside WattMarkets today — same instrument, twelve scoreboards. The Impact Estimator (enter a load profile, see the charge shift under the draft methodology) ships when the draft rule text is published.