Infrastructure Briefing — July 12, 2025
FERC Order No. 901 entered its dynamic line rating compliance phase, requiring transmission owners to evidence ambient-adjusted ratings and grid monitoring controls by year-end 2025.
Executive briefing: The Federal Energy Regulatory Commission’s Order No. 901 reached its first compliance milestone on July 12, 2025, compelling transmission providers to implement ambient-adjusted ratings (AAR) and develop implementation plans for dynamic line ratings (DLR). Utilities must now document telemetry, forecasting, and control room procedures that unlock additional transmission capacity while safeguarding grid reliability.
Key infrastructure signals
- AAR enforcement. Transmission providers must apply hourly AAR calculations across their systems and submit compliance documentation to their regional transmission organizations.
- DLR plans. Order No. 901 requires utilities to file DLR implementation plans within six months, detailing sensor deployments, communications upgrades, and cybersecurity controls.
- Independent monitoring. FERC directed reliability coordinators to audit telemetry accuracy and contingency modelling as AAR data begins influencing dispatch decisions.
Control alignment
- NERC FAC-008 and MOD standards. Update facility ratings methodologies and modelling data to incorporate ambient adjustments and future DLR metrics.
- CIP-005 and CIP-013. Harden communications paths for new line sensors and ensure supply chain risk management covers DLR vendors.
- DOE grid resilience grants. Map funding applications to AAR/DLR deployment schedules to capture federal cost-share opportunities.
Detection and response priorities
- Deploy anomaly detection on line rating telemetry to flag sensor drift, missing data, or cyber anomalies before they impact dispatch.
- Exercise control room playbooks for rapid reversion to seasonal ratings if DLR telemetry fails or communications links degrade.
Enablement moves
- Educate executives and regulators on capacity gains achievable through AAR and DLR, linking them to congestion cost reductions.
- Coordinate with regional operators to align outage scheduling, real-time visibility, and data sharing for DLR-enabled circuits.
Sources
- Federal Energy Regulatory Commission: Order No. 901 (November 9, 2023)
- FERC news release: FERC reminds utilities of dynamic line rating compliance deadlines (July 12, 2025)
Zeph Tech equips transmission owners with telemetry governance, cybersecurity controls, and regulatory reporting that keep dynamic line rating programs compliant and grid-safe.