Utilities are increasingly writing large load tariffs that require upfront payment for system impact studies, set a fixed schedule for ramping to full load, and impose an exit fee for early termination, according to a technical brief from Lawrence Berkeley National Laboratory and the Brattle Group.
These practices have grown more common in the 18 months since the researchers conducted a survey in January 2025. The analysis draws on the Halcyon large load tariff tracker, which as of August 17, 2026 cataloged 264 tariff filings covering data centers, advanced manufacturing and other large industrial customers. Active and proposed large load tariffs have risen sharply since early 2025, as has the average qualifying demand threshold.
Researchers examined 55 tariffs and isolated 18 distinct elements across four categories. Eight established elements appear in more than two thirds of large load tariffs, and five of those impose a minimum commitment measured in duration or dollars. Minimum demand thresholds ranged from under 1 megawatt to 150 megawatts.
Natalie Mims Frick, who leads the energy markets and planning department at Lawrence Berkeley National Laboratory, said some tariffs measure thresholds in aggregate across sites while others apply them site by site. The Entergy Louisiana Large Power, High Load Factor Power Service Rate carries a five year minimum, and the El Paso Electric proposed High Load Factor Power Service carries a 20 year minimum. Tariffs proposed before 2025 averaged five year minimums, while those filed after 2025 averaged 12 years.
Emerging elements include nonrefundable study deposits, ramp schedules, hold harmless cost shortfall provisions, load resizing conditions and substantial exit fees. The one element in decline restricts which customer types may take service under the tariff.
Source: Utility Dive - https://www.utilitydive.com/news/large-load-tariffs-lbnl-brattle/829796/