What is a Transmission Security Agreement?

A Transmission Security Agreement is a contract that ties grid upgrade costs to actual usage. Developers post financial security and agree to milestones. If the project delivers the promised load, costs flow through normal rates. If it underdelivers, the developer covers certain transmission costs, reducing the chance that existing customers pay for underused infrastructure.

Will these agreements lower Illinois electricity rates?

They do not directly cut bills, but they help keep rates from rising due to projects that fall short. By shifting risk to developers when load underdelivers, the agreements protect customers from paying for transmission built for megawatts that never arrive. The result is steadier bills and more confidence in cost causation.

How big is the data center power demand behind this move?

ComEd linked the agreements to 6.5 GW of proposed large loads. A single large data center can require 100 to 300 MW in phases, so multiple sites can quickly add gigawatts of demand. TSAs help align long transmission timelines with that growth so spending matches actual, metered usage over time.

What should investors watch next?

Watch for additional TSA signings, interconnection milestones, and regulatory feedback in Illinois. Track timing of transmission approvals, material lead times, and any rate case commentary about cost recovery. For developers, monitor security requirements, phasing plans, and tenant commitments, which can determine whether projects meet load targets and avoid penalties.

Global Market Insights

January 10: ComEd Locks In TSAs to Shield Customers from Data-Center Costs

ByHuzaifa Zahoor January 10, 2026January 10, 2026

ComEd locked in eight Transmission Security Agreements tied to 6.5 GW of proposed large loads, a direct response to accelerating data center power demand. The deals shift more than $2 billion in 10-year transmission costs away from existing customers if projects underdeliver. For Illinois electricity rates, this approach helps limit bill impacts while keeping growth on track. For investors, it clarifies risk, capex timing, and regulatory posture as AI computing reshapes grid planning in the Midwest and beyond.