12CP

12CP allocates transmission costs using the highest system-demand interval of every month, not just the four summer months. The PUCT is considering moving ERCOT from 4CP toward a 12CP-style methodology; a final rule is mandated by the end of 2026. The practical effect: peak-chasing spreads across the whole year, winter peaks start to matter, and the response strategy that worked under 4CP needs rethinking. WattMarkets ships a 12CP preview program so you can see the new exposure before the rule lands.