Why a Standard Large-Power Tariff Isn’t Enough for Large Load Customers
Every utility has a large-power tariff. It might be called the General Service—Extra Large tariff, or the Industrial Power tariff, or some similar designation. It typically applies to customers above a certain demand threshold—often 1,000 kW or 5,000 kW or higher—and it establishes the rates, terms, and service conditions for the utility’s biggest customers.
These tariffs have served utilities and their large industrial customers well for decades. They were designed for foundries, chemical plants, paper mills, and other large manufacturers whose load characteristics—predictable, continuous, shaped by production cycles—the tariff writers understood well.
Today’s large load customers — large load customers, crypto mining facilities, hydrogen electrolyzers, large EV charging hubs, and large industrial electrification projects — are structurally different from the industrial loads these tariffs were designed for. Not just bigger, but different in load profile, infrastructure requirements, and financial risk. Utilities that serve these customers under standard tariffs without supplemental agreement terms are accepting risks those tariffs were never designed to address.
What Standard Large-Power Tariffs Were Designed For
Standard large-power tariffs share a set of design assumptions that reflect the industrial load profile they were built around:
- Relatively stable load: Industrial plants typically run continuous processes that produce predictable monthly demand peaks
- Long-term operational commitment: A steel mill or chemical plant has high switching costs and is unlikely to disconnect without substantial advance notice
- General-purpose infrastructure: The distribution infrastructure serving a large industrial customer is typically part of the general distribution system and can serve other loads if the industrial customer leaves
- Commodity-like service: Power is power—the industrial customer needs electricity for its process, and the tariff provides it
These assumptions produce tariff structures built around monthly demand billing, energy charges, power factor requirements, and curtailment provisions. They are adequate for the loads they were designed for. They are inadequate for large load customers.
Five Gaps in Standard Large-Power Tariff Coverage
Gap 1: Scale and Infrastructure Dedication
A standard large-power tariff typically does not distinguish between load served by general-purpose distribution infrastructure and load served by dedicated, single-customer infrastructure. When a utility builds a dedicated 230-kV substation for a large load customer, that infrastructure does not fit the tariff’s assumption of general-purpose service.
Standard tariffs do not include provisions for dedicated infrastructure cost assignment, dedicated rider charges, or the special termination obligations that dedicated infrastructure creates. Serving a large load customer under a standard tariff leaves the utility with no mechanism to assign dedicated infrastructure costs to the customer who caused them.
Gap 2: No Minimum Bill Tied to Infrastructure Costs
Standard large-power tariffs typically include some form of minimum bill or demand charge, but those minimums are designed around the economics of shared system capacity, not dedicated infrastructure. A ratchet clause that bills 85% of the maximum demand in the previous 12 months provides meaningful cost recovery for shared infrastructure. It does not provide adequate cost recovery for a substation built exclusively for the large load customer.
When a large load customer reduces its load—because it has consolidated operations, shifted workloads to another facility, or is in the process of exiting the agreement—a standard tariff minimum bill does not recover the carrying costs of the dedicated infrastructure that remains in service and on the books.
Gap 3: No Early Termination Protection
Standard large-power tariffs typically allow large customers to terminate service with 30 to 90 days’ notice. That notice period is adequate when the utility’s investment in serving the customer is recoverable through general rates and the infrastructure can serve other loads.
It is completely inadequate when the utility has built hundreds of millions of dollars in dedicated infrastructure. A 90-day termination notice from a large load customer customer served under a standard tariff would leave the utility holding stranded infrastructure with no contractual recourse beyond the standard tariff provisions.
Gap 4: Load Profile and Power Quality Mismatches
Standard tariffs typically address power quality through a power factor clause and technical service specifications that reflect the load characteristics of traditional industrial customers. Large load customers — particularly large load customers serving AI inference workloads, electrolyzers with variable production schedules, and crypto mining facilities that can curtail entirely — present load characteristics that standard specifications may not adequately address.
AI inference loads can exhibit sharp demand spikes and high variability that stress distribution infrastructure differently than steady-state industrial loads. The transformer sizing, switching equipment specifications, and protective relay settings appropriate for a large load customer serving AI workloads may differ significantly from those specified in a standard tariff’s service requirements.
Gap 5: No Assignment and Creditworthiness Provisions
Standard tariffs generally do not impose creditworthiness requirements or assignment restrictions beyond what is standard for any service account. A large industrial customer is typically required to pay a standard deposit, maintain a reasonable payment history, and notify the utility of ownership changes.
These provisions are not adequate for the relationship a utility enters into when it builds dedicated infrastructure for a large load customer. The utility needs to know who it is serving, assess that party’s creditworthiness throughout the agreement term, and have contractual rights that prevent the service relationship from being assigned to a weaker counterparty without utility consent.
FERC is expected to issue a ruling in June 2026 establishing a federal framework for connecting large electricity users — including large load customers exceeding approximately 20 MW — directly to the transmission grid. The proceeding (Docket RM26-4-000, Interconnection of Large Loads to the Interstate Transmission System) is expected to address standardized interconnection study requirements, deposit and readiness standards, network upgrade cost allocation, and the boundary between FERC-jurisdictional transmission matters and state authority over retail service and distribution.
The content in this article reflects current practice under existing tariff structures. Readers should monitor the June 2026 FERC order for requirements that may affect how utilities structure agreements, assign infrastructure costs, and design rates for large transmission-connected loads. This page will be updated following the ruling.
What Needs to Replace or Supplement the Standard Tariff
Utilities serving large load customers have two structural options: develop a new tariff specifically designed for hyperscale loads, or supplement the standard large-power tariff with a service agreement that addresses the gaps described above.
The Dedicated Data Center Tariff Approach
A purpose-built large load customer tariff would include, at minimum:
- Load threshold provisions identifying when the tariff applies (typically above a minimum demand threshold that distinguishes hyperscale from standard large-power customers)
- Dedicated infrastructure cost assignment mechanisms or rider provisions
- Minimum bill provisions tied to infrastructure carrying costs, not just general rate base
- Extended notice period requirements for service termination, calibrated to infrastructure depreciation timelines
- Creditworthiness and security deposit requirements appropriate to the infrastructure investment
- Assignment restrictions that require utility consent and successor creditworthiness assessment
A purpose-built tariff has the advantage of regulatory approval: once approved by the commission, its terms apply to all customers that qualify, reducing the negotiation burden on individual agreements. Its disadvantage is inflexibility—tariff terms cannot be customized for individual customers in ways that service agreements can.
The Supplemental Service Agreement Approach
Many utilities have chosen to maintain their standard large-power tariff as the baseline service vehicle while negotiating supplemental service agreements that address the gaps described above. The service agreement rides on top of the tariff and provides the contractual protections that the tariff does not.
This approach allows flexibility in structuring the protections to match the specific infrastructure investment and customer situation. It requires more negotiation effort per customer, but it allows the utility to tailor the agreement to the actual risk profile of each large load customer relationship.
For a detailed discussion of the provisions these supplemental agreements should include, see our article on Six Provisions Every Data Center Developer Agreement Should Include.
The Regulatory Dimension
Whether a utility chooses a new tariff or a service agreement approach, regulatory engagement is essential. Commissions have generally been receptive to utility requests for tariff modifications or approval of service agreement frameworks for large load customers, provided that the ratepayer protection provisions are adequate. Some states have proactively issued guidance or orders establishing requirements for large load customer service arrangements.
Utilities that serve large load customers under standard tariffs without supplemental protections—and without regulatory awareness that they are doing so—face a double exposure: the financial risk described above and the regulatory risk of being found to have failed to adequately protect ratepayers when that standard tariff proves inadequate.
Disclaimer: The material in this article is for informational purposes only and should not be taken as legal or accounting advice provided by Utility Accounting & Rates Specialists, LLC. You should seek formal advice on this topic from your accounting or legal advisor.