Utility Tariff Analysis · Updated September 2026

Arizona Public Service's XHLF Tariff: What It Means for AI Data Centre Siting in Arizona

High load factor customers identified in APS's 2025 rate review are addressed through proposed changes to the XHLF (Extremely High Load Factor) Tariff, filed as part of a larger rate review to put reasonable cost-recovery terms and risk-based conditions in place for this customer class.

Arizona Public Service's XHLF Tariff — AI data centre infrastructure

Arizona Public Service's XHLF Tariff

AZ

Arizona Public Service (Pinnacle West)

E-01345A-25-0105

Regulatory docket / filing reference

High load factor customers identified in APS's 2025 rate review

Who the tariff applies to

High load factor customers identified in APS's 2025 rate review are addressed through proposed changes to the XHLF (Extremely High Load Factor) Tariff, filed as part of a larger rate review to put reasonable cost-recovery terms and risk-based conditions in place for this customer class.

Also active in Arizona: APS is also serving a landmark manufacturing load: Taiwan Semiconductor's Phoenix fab expansion, now valued at $165 billion, ramping from 200 MW in its first phase to roughly 1,000 MW at full build-out. APS has proposed a 2,000 MW natural gas plant partially available to large-load customers under a subscription model.

Named Projects Already Underway

CustomerLocationDetails
Taiwan Semiconductor Manufacturing Company (TSMC)Phoenix, AZ$165 billion semiconductor manufacturing expansion, ramping to approximately 1,000 MW
Beale InfrastructureTucson, AZ (Tucson Electric Power)data centre project; TEP estimates a typical residential customer will save about $13/month from the 300 MW of associated load growth

Figures compiled from the Edison Electric Institute's "Large Load Projects and Tariffs" (September 2026) member-company summary and public regulatory filings. Confirm current tariff terms directly with Arizona Public Service (Pinnacle West) and the relevant state public utility commission before relying on any figure for a capital decision.

Weighing Arizona against another state or a Canadian province with a different rate and interconnection picture entirely? Run both sides of the comparison through our licensed AI data centre cost configurator — it applies each jurisdiction's actual power rate, tax treatment and large-load tariff rules to the same seven build configurations.

Model This State on Your Own Site

Every figure above comes from the same power-cost and tariff dataset behind the SCR AI Build Configurator — a licensed, embeddable widget that models seven data centre build configurations against all nine Canadian provinces and all 50 US states plus DC, returning capital expenditure by line item, energy cost, revenue by commercial structure, EBITDA and payback.

LicencePrice (CAD)Who it suits
Standard$4,000 / domain / yearAdvisors who need three lease-model configurations and a clipboard summary
Pro$10,000 / domain / yearConsultants who send CSV deliverables to clients and want all seven configurations
EnterpriseFrom $25,000 / year, up to 3 domainsDevelopers and EPC firms who want the model on their own cost basis with attribution removed

Not ready for an annual licence? A one-time Site Screening Report ($950, one site) runs the same model for a single build without embedding anything.

Frequently Asked Questions

What is Arizona Public Service's XHLF Tariff?

High load factor customers identified in APS's 2025 rate review are addressed through proposed changes to the XHLF (Extremely High Load Factor) Tariff, filed as part of a larger rate review to put reasonable cost-recovery terms and risk-based conditions in place for this customer class.

Why did Arizona Public Service (Pinnacle West) introduce this large-load structure?

To ensure the cost of new generation, transmission and distribution infrastructure built to serve very large customers, chiefly hyperscale data centres, is paid for by those customers rather than spread across the general rate base of residential and small commercial ratepayers.

What large data centre projects are already active in Arizona?

APS is also serving a landmark manufacturing load: Taiwan Semiconductor's Phoenix fab expansion, now valued at $165 billion, ramping from 200 MW in its first phase to roughly 1,000 MW at full build-out. APS has proposed a 2,000 MW natural gas plant partially available to large-load customers under a subscription model.

Does this tariff replace Arizona's standard commercial and industrial rates?

No. Arizona Public Service's XHLF Tariff sits above Arizona Public Service (Pinnacle West)'s standard commercial and industrial rate schedules and applies specifically to customers that meet or exceed the large-load threshold described above. Smaller commercial and industrial loads continue to be billed under existing rate schedules.

How can I model a Arizona data centre build against this tariff and other states?

The SCR AI Build Configurator applies Arizona's power cost, tax treatment and large-load tariff rules alongside all other US states and Canadian provinces, so a Arizona scenario can be compared line-by-line against any alternative site.