ISO/RTO Market Fundamentals
Market structure, governance, and stakeholder committees for the ISOs/RTOs that matter for hyperscale interconnection.
Lessons
PJM market structure — RTO governance + capacity market mechanics
PJM serves 65M people across 13 states + DC. Governance: Members Committee (MC), Markets & Reliability Committee (MRC), Operating Committee (OC), Transmission Expansion Advisory Committee (TEAC). Markets: Day-Ahead Energy (DAM) + Real-Time Energy (RTM, 5-min) + Capacity (RPM, three-year-forward Base Residual Auction) + Ancillary Services (regulation, synchronized reserves, primary reserves, frequency response). RPM clears MW commitments at the Variable Resource Requirement (VRR) curve intersection with supply.
ERCOT market structure — energy-only ISO, no capacity market
ERCOT covers ~90% of Texas load — ~30M Texans, 85.5 GW summer peak (Aug 2024). Texas-only intrastate ISO; minimal FERC role — PUCT and TX Legislature regulate. Energy-only design: no capacity auction; revenue adequacy via Operating Reserve Demand Curve (ORDC) scarcity adder. System-wide offer cap = $5,000/MWh (lowered from $9,000 by SB 3 / SB 7 post-Uri 2021). Markets: hourly DAM + 5-min RTM SCED + 5 ancillary products (Reg Up/Down, RRS, Non-Spin, ECRS new in 2023). Governance: ERCOT Board + PUCT + stakeholder stack TAC → ROS / WMS / PRS. Large-load framework: PUCT §25.494 Batch Zero (≥75 MW).
MISO / SPP / CAISO overview — secondary hyperscale targets
Tier-2 RTOs after PJM + ERCOT. MISO: 15 states + Manitoba, ~45M people, ~125 GW peak. Seasonal Planning Resource Auction (PRA, 4 seasons since 2023) with ELCC accreditation; OMS coordinates state regulators; LRTP1+LRTP2 ~$30B planning. SPP: 14 states, ~21M people, ~50 GW peak. Integrated Marketplace (2014) combines DAM/RTM/A.S.; 12% reserve margin (no capacity auction); Markets+ initiative (formerly Western RTO) expanding into the West 2026-27. CAISO: ~32M Californians, ~45 GW peak; hourly DAM + 15-min FMM + 5-min RTD; Resource Adequacy administered by CPUC (System / Local / Flexible); EIM (2014, 22 BAAs) + EDAM (2025-26) extend market into West; >13 GW BESS deployed; SB 100 drives 100% zero-emission by 2045.