Without Compromising Speed to Power: The California ISO's Issue Paper on Large Loads

The California Independent System Operator published an issue paper on large loads on January 30, 2026. The paper calls data centers "a significant driver" of the growth in demand it expects, and names electric vehicle charging and the electrification of agricultural and industrial processes as well. The paper "describes the ISO's current role in integrating large loads on the ISO grid and identifies issues that may arise in future stakeholder discussions." It makes no specific proposal. Parts of it follow, not the whole.

Who Connects a Large Load

The current assignment of responsibilities "gives lead responsibilities for generation interconnection and transmission planning to the ISO, and load interconnections to the utilities." As such, utility federal and state tariffs and state regulations "generally govern the study, interconnection, rates, and cost recovery for serving new loads, with active participation by the ISO." A data center connects through its utility.

A footnote gives the state's word for it. The state's utility commission, the paper says, refers to load interconnection as "energization." California agencies are examining "the implications of large load planning, interconnection, and energization" in open proceedings, it adds, while federal regulators are at work on the same questions.

The paper also reports a state proceeding on a tariff. In November 2024 a utility proposed Electric Rule 30, a standardized tariff for large load customers applying for retail service at transmission-level voltages, defined as voltages between 50 kV and 230 kV. In July 2025 the commission approved interim implementation, "with the caveat that customers interconnecting under Electric Rule 30 would cover the full initial infrastructure costs" while it went on weighing cost causation, cost allocation and cost recovery.

The Forecast Behind the Plan

As of January 2026, the paper says, the California Energy Commission forecasts data center load in the ISO's area to increase by 1.8 GW by 2030 and by 4.9 GW by 2040. The ISO "also is aware that utilities are receiving an increasing number of large load interconnection and service applications."

For data centers, the energy commission "gathers information on applications for service submitted to utilities and applies adjustments to requested capacity based on utilization factors, confidence levels, and ramping assumptions." A project with a signed agreement for electric service lands in the highest confidence group. The ISO's annual transmission planning is "highly integrated with statewide load forecasts," and the paper says recent plans included approvals and changes to earlier projects "to provide increased capacity in the Bay Area to support data center load growth and position the system for additional expansion."

Speed to Power

The ISO "is considering commencement of a policy initiative to ensure maintenance of a reliable system without compromising economic development or speed to power." It also says it "anticipates additional clarity from FERC before issuing specific proposals."

Transmission service for load on the ISO's grid "is generally firm," it says. The federal regulator recently directed another grid operator to establish new transmission services that reflect that eligible customers taking service on behalf of co-located load "are willing and able to limit their energy withdrawals from the transmission system under certain conditions." The ISO, which does not have various levels of transmission service, "could face an equivalent requirement to provide load interconnection customers with interconnection timelines based on willingness to be curtailed." The ISO "understands that offering customized service to large loads (e.g. interruptible service or being the first-in-line to be curtailed) may enable faster interconnection," which it also calls speed to power, "by providing some interim, potentially reduced level of non-firm service to the large load as system reinforcements are built."

The faster connection in that passage comes, if at all, with service that is interim, possibly reduced and non-firm while the grid is reinforced.

In its section on operational requirements, the paper says that "Under evolving federal policy (e.g., FERC ANOPR concepts), large loads that agree to be curtailable or hybrid facilities that agree to be dispatchable may qualify for expedited load interconnection." Such loads, it says, must provide telemetry, planned operating schedules and outage notices, "24/7 curtailment capability for curtailable large loads," and an acceptable ramp rate.

Requirements and Costs

In October 2025 the ISO set up an informal working group of utilities with active large load interconnection requests, to study and develop a coordinated set of technical requirements for connecting data center loads to its grid. The requirements cover models, power quality, rapid ramping and ride-through, among other things. Where those requirements will be "documented and enforced" is to be decided "at a later stage." Subject to resource availability, the working group was targeting a first draft by the end of the first quarter of 2026.

On cost, the paper says that for co-located facilities with load and generation on site, "It will not be possible in many instances to distinguish between which networked facilities were triggered by the load or by the generation." Large loads co-located with generation or storage that are subject to federal jurisdiction are studied in separate interconnection processes, the load through the transmission owner and the generator through the ISO, and the ISO's tariff "currently does not have a mechanism to consider large loads in its generator interconnection study process."