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The second-largest US grid operator wants data centers to prove they won't destabilize the power grid before plugging in
The Midcontinent Independent System Operator, better known as MISO, filed a proposal with the Federal Energy Regulatory Commission on August 28 that would impose new interconnection reliability requirements on large electricity consumers. The primary target: data centers powering the AI boom that are gobbling up power at a pace the grid wasn’t designed to handle.
MISO operates the second-largest electrical grid in the US, spanning 15 states and the Canadian province of Manitoba.
What the new rules actually require #
The proposal defines “large loads” as facilities drawing more than 50 MW at a single location and connecting at voltages above 69 kV. For context, 50 MW is roughly enough to power 40,000 homes. A single hyperscale data center can consume several times that amount.
Computational loads, a category that covers data centers specifically, face even tighter scrutiny. Any facility with at least 25 MW of demand from IT equipment would need to meet additional requirements around advanced modeling, frequency ride-through capabilities, and voltage ride-through performance.
The framework covers four main areas. First, visibility requirements that force large consumers to share operational data and telemetry with grid operators. Second, ramp-rate management rules that prevent facilities from surging their power consumption too quickly. Third, ride-through performance standards for surviving grid disturbances without disconnecting. Fourth, broader operational expectations that give MISO ongoing oversight authority.
MISO has requested an effective date of December 4, 2026, with additional filings on transmission products and cost-shift protections due by November 16, 2026.
The grandfathering question #
Not every large power consumer will face the new regime. MISO included grandfathering provisions that exempt most existing large loads from the stricter requirements. The carve-out covers an estimated 30 GW of service. MISO retained the authority to monitor these grandfathered loads and intervene if reliability issues emerge.
The real impact falls on new builds and expansions. Any data center developer planning to break ground after the rules take effect will need to design their facilities with these requirements baked in from the start.
Why this is happening now #
The filing is a direct response to FERC directives issued in June 2026, which instructed grid operators to develop rules addressing reliability risks from large-load interconnections.
MISO isn’t the first grid operator to grapple with this problem. PJM Interconnection, the largest US grid operator covering much of the eastern seaboard, has been wrestling with a backlog of interconnection requests driven largely by data center demand.
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