The disclosure and our analysis
Evidence dates
Evidence: California ISO news release, October 28, 2026; California ISO stakeholder presentation with the compliance schedule, October 19, 2026. Read November 2, 2026. Status is as of October 28, 2026.
What the board approved
According to the ISO, the board approved a proposal responding to FERC's June show cause order, which directed the California ISO and five other grid operators and their transmission owners to show they have rules for connecting large loads quickly without compromising reliability or shifting costs to other customers. The order instituting the proceeding was issued June 18, 2026. [Source 1] [Source 2]
The ISO describes these elements: [Source 1]
1. **Flexible interim load interconnection:** large loads could interconnect to the transmission system with enforceable flexibility, determined by grid conditions and constraints, until the associated network upgrades are complete.
2. **Faster study review:** a new monthly window for the ISO to review transmission additions or upgrades tied to large loads that fall outside the usual planning cycle, to fit FERC's 60 to 90 day requirement for transmission owners' load interconnection studies.
3. **Cost shifting:** a framework to prevent cost shifting to other customers. The release does not describe its terms.
4. **Co-located load and generation:** parallel information and application requirements for co-located arrangements, so the ISO has full visibility.
5. **Future policy work:** consideration of studying generation for loads located at separate but nearby sites.
The ISO also proposes technical requirements: hourly forecasts, telemetry and other operational data; communication protocols so the ISO and the transmission owner can remotely disconnect large loads when necessary to maintain reliability; and maintained communication channels with transmission customers serving large loads. The ISO says it will keep working with NERC on reliability standards for computational loads. [Source 1]
Timeline
The ISO's compliance schedule lists the October 28 board consideration and Section 205 tariff filings from the ISO and its participating transmission owners on November 16, 2026. FERC will then decide whether the proposal satisfies its show cause order. [Source 1] [Source 2]
Status
On our status vocabulary, as of October 28, 2026: the proposal is Approved by the California ISO Board of Governors for filing at FERC. It is not yet filed or accepted by FERC, and the reviewed sources give no effective date. The release does not give a megawatt threshold for what counts as a large load.
Buyer analysis
This is our analysis. The flexible interim service is the part that matters most for timing. If FERC accepts it, a California data center could take transmission service before its network upgrades are finished, but on terms that let the grid limit its load. Capacity delivered that way is not the same as firm power, and buyers should ask providers whether a site's early service is interim and flexible, and when firm service is expected.
The remote disconnect and hourly forecast requirements also flow down to tenants. Operators connecting under these rules will need curtailment plans and backup arrangements. Tenants in Silicon Valley, Los Angeles and other California markets should ask how a provider would handle a grid directed reduction, and whether their contract covers it.
