Energizing a data center in PJM increasingly means understanding a large-load utility tariff or a related service agreement. Despite the numerous approaches across utility territories, modeled delivered costs fall within a narrow range of each other.

A tariff is the rate applying to all customers of a certain class that a utility files with its state commission. Once approved it becomes public and applies to every customer meeting its eligibility test. A large-load tariff carves a new customer class out above a size threshold, generally 25 to 100 MW. All customers in that class are then billed for usage in tariff-prescribed terms.

There are some common approaches for stabilizing utility revenue, including:

• Firm-service commitments that require a customer pays for ten years or longer,
• Minimum-payment requirements that generally range from 50% to 85% of a defined billing quantity, and
• Collateral, direct facility charges, or other protections against a project failing to materialize.

Minimum bills, collateral, and contract terms limit the revenue risk if the project arrives late, is smaller than planned, or does not materialize.

The utilities that have the most active data center capacity are also the utilities with the most developed large load tariffs. These include Dominion, ComEd, AEP, and PPL, which together account for 84% of the projected buildout.

Tariff coverage extends across most of the projected data center buildout.

Of PJM's 38.8 GW of projected 2030 data-center demand, 32.7 GW sits in a zone with a large-load tariff or a requirement to develop one. Another 5.2 GW sits in ComEd, which secures large loads through transmission security agreements rather than a filed rate class. The remaining 0.9 GW sits in PECO, Met-Ed, and Duquesne, which have no comparable framework. These sorts of agreements take place on a case-by-case basis and are specific to the network impact of a project, so they cannot be generalized.