A huge, proven ecosystem (Silicon Valley), but for a new large load it is expensive, supply-tight into the evening ramp, and queue-constrained. Momentum keeps it from falling further; access and cost keep it out of Tier 2.
See live grid data →Why: FERC's 18 June 2026 Section 206 show-cause order directs CAISO to justify or rewrite its large-load and co-location tariff terms, so the rules for connecting a data centre are formally in flux; California's high retail costs and its own cost-allocation review add friction on top.
What would change the read: The Section 206 process settling on clear large-load connection and cost-allocation rules, and California resolving who pays for the supporting build.
Constrained access: deep cluster-study queue, storage-heavy backlog.
Tight availability: the evening net-load ramp as solar fades.
High cost.
High momentum: the established Silicon Valley cluster.
Carbon moderate (~230 g), solar-and-gas with heavy storage.
ISO-ordered rotating outages during the August 2020 heat wave (about 492,000 customers cut on Aug 14) show supply-shortfall load-shedding risk at peak.
What this means: A large new load should expect genuine exposure to forced power cuts (curtailment), price spikes, and delays in getting connected, and should design in backup power or firm supply contracts.
event-based · CAISO rotating outages fact sheet
Average customer interruption (SAIDI) of 177.06 minutes per year in 2024, excluding major event days as filed. Public Safety Power Shutoffs: utilities proactively de-energize lines during wildfire-risk weather, so a load can lose grid power for reasons unrelated to its own site.
What this means: A large new load should expect genuine exposure to forced power cuts (curtailment), price spikes, and delays in getting connected, and should design in backup power or firm supply contracts.
event-based · CPUC Public Safety Power Shutoffs · EIA Form 861, Schedules 3B and 3C (annual electric power industry report) (IEEE 1366 major-event treatment, customer-weighted blend of 4 of 4 territories, 100% of customers, regional context only)
The market figure above is an average across these territories. A project sits in one of them, not in the average. Each row is that operator’s own filed record; once a candidate site is matched to a territory, that row is the evidence that applies to it.
| Territory operator | SAIDI min/yr | Customers | Major-event method |
|---|---|---|---|
| Pacific Gas & Electric Co. (CA) | 275.6 | 5,795,693 | IEEE 1366 |
| Southern California Edison Co (CA) | 100.25 | 5,316,264 | IEEE 1366 |
| San Diego Gas & Electric Co (CA) | 71.13 | 1,527,274 | IEEE 1366 |
| City of Santa Clara - (CA) (CA) | 161.73 | 60,620 | IEEE 1366 |
Filed to EIA Form 861 for 2024, excluding major event days. Territory-wide averages: see the layer note above for what they do not establish.
NERC's 2024 assessment rates California elevated-risk, with extreme heat likely to cause reserve shortfalls.
What this means: A large new load faces occasional exposure here. Monitor conditions and keep a contingency plan.
assessed · NERC 2024 Long-Term Reliability Assessment
We have not compiled what firm service actually promises here: whether it is firm, non-firm or interruptible, the conditions under which you can be curtailed, the redundancy required of you, and the transfer time behind any N-1 commitment. Treat this as an open diligence item, not as an indication that service is firm.
Utility feeds, UPS, storage, on-site generation, islanding, black start and the residual energy you still expect to lose are properties of a specific site design, not of a market. This layer only exists once there is a site, and we never assert it for you.
What this means: Supply and demand look broadly balanced; the outcome hinges on the drivers below.
The average customer loses about 177.06 minutes of power per year (2024). This is the standard regulator outage measure (SAIDI); lower means a more reliable grid.
Averaged across 4 territories. No single customer experiences this figure. The per-territory table in the reliability overlay above gives each operator’s own filed record, which is what a site-specific read needs.
191 GW
60 months
The full queue analysis for this market, which covers the share of projects that give up and leave the queue (the withdrawal rate), how much of the queue is data centers, and the sources, is available through /api/v1/queue/caiso with a paid key. These are generation and storage queue figures: they show interconnection-system congestion, not a typical large-load connection wait.
$95 to $155 per MWh
Midpoint about $120 per MWh
California's wholesale price badly understates the delivered cost. A large load carries some of the highest non-bypassable and delivery charges in the United States, so an all-in figure of roughly $95 to $155 per MWh is realistic, well above the $42 wholesale reading. On this basis California is an expensive market for a new large load, not a cheap one.
This market's band is free here; the ranked cross-market table with every market's precise midpoint is the Analyst Desk. See the ranked view.
Basis: triangulated from public sources, in US dollars per MWh delivered to a large high-load-factor load, excluding refundable taxes. Sources: CPUC on data-center cost allocation · CAISO large loads and Rule 30.
High
2 of 3 data layers measured
Full
3 of 3 dimensions: reliability, connection, cost
June 2026
per-layer vintages below
| Layer | Method | Vintage | Freshness | Source |
|---|---|---|---|---|
| PGIQ Rating opinion | opinion | June 2026 | Current | PGIQ methodology |
| Reliability | measured | 2024 | Fresh | EIA Form 861, Schedules 3B and 3C (annual electric power industry report) (IEEE 1366 major-event treatment, customer-weighted blend of 4 of 4 territories, 100% of customers, regional context only) |
| Interconnection queue | measured | end-2025 (LBNL 2026) | Fresh | LBNL Queued Up 2026 |
| Realized cost | triangulated | 2026 | Fresh | CPUC on data-center cost allocation |
Freshness reflects each layer's refresh cadence: reliability annual to three-yearly, capacity-auction and queue yearly, tariffs every year or two. The full cross-market freshness dashboard is at /data-quality.
Territories in this market, each with its own filed record: Pacific Gas & Electric Co., Southern California Edison Co, San Diego Gas & Electric Co, City of Santa Clara - (CA). Which one serves a given site depends on where that site is.
How the connection process is organised: the applicable service and connection entities depend on the candidate location and the power pathway. We have not compiled the structure for this market; that is a gap in our wayfinding, not a fact about the market.
How CAISO (California)'s reliability-adjusted score and tier have moved, month by month. Part of your Analyst Desk.
Every field above carries its own source and freshness. Price, imports and exports are modelled in every market because no feed supplies them. Carbon intensity is derived from the fuel mix.
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