FERC Finalizes Rule Mandating Interregional Electric Transmission Capacity Standards

WASHINGTON — Federal Energy Regulatory Commission (FERC) Chairman Willie Phillips announced on Monday the final adoption of a transformative federal rule requiring regional transmission organizations (RTOs) and independent system operators (ISOs) to establish mandatory minimum interregional power transfer capacities between adjacent power grids.

The landmark order requires neighboring grid operators—such as PJM Interconnection, Midcontinent ISO (MISO), and the Southwest Power Pool (SPP)—to jointly plan and construct high-voltage direct current (HVDC) transmission lines capable of transferring at least 30 percent of peak seasonal electric load between regional markets during extreme weather emergencies.

Preventing Catastrophic Grid Failures During Extreme Weather Events Historical winter storms (such as Winter Storm Uri and Winter Storm Elliott) triggered deadly localized blackouts because regional grids operate in isolated silos, unable to import surplus electricity from sunny or windy neighboring states that possessed excess generating reserves.

"The American power grid is an interconnected machine, yet outdated regulatory barriers have prevented our regional grids from sharing power when extreme weather strikes," FERC Chairman Willie Phillips said in Washington. "Today's historic rule breaks down regional silos and mandates minimum interregional transfer capacity. By building strong high-voltage transmission interties between regions, we are ensuring that when a winter freeze or heatwave strikes one part of the country, neighboring regions can instantly send life-saving electricity across state lines."

Key Provisions of the FERC Final Rule Under the enacted federal standard:

• 30 Percent Minimum Interregional Capacity: Regional grid operators must submit joint 20-year transmission plans establishing minimum 30 percent power transfer capabilities by 2030.
• Shared Cost Allocation Framework: Establishing clear statutory cost-sharing formulas based on multi-value economic benefits, reliability metrics, and extreme weather risk reductions.
• Fast-Track Interconnection Protocols: Eliminating duplicate environmental reviews for interstate HVDC lines utilizing existing railroad and highway rights-of-way.

Clean energy developers, industrial electricity consumers, and state utility commissioners praised the commission's decisive action, highlighting that interregional transmission unlocks vast renewable energy reserves while ensuring grid resilience.