What changed in this filing

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Item 2. Properties

2026-02-25 compared with 2025-02-25 · 28 added, 22 removed, 67 unchanged (43% of the section changed)

Generation Facilities

APS’s portfolio of owned generating facilities as of December 31, 2024 is provided in the table below:

APS’s portfolio of owned generating facilities in commercial operation as of the date of this report is provided in the table below:

Owned (a) Principal

2 unchanged sentences

Four Corners 4, 5 (c) 2 63 % Coal Base Load 970

Cholla 1,3 2 Coal Base Load 380

Total Steam 970

11 unchanged sentences

Yucca 4 1 Oil Peaking 54

Yucca 5, 6 2 Gas Peaking 90

Total Combustion Turbine 1,708

16 unchanged sentences

(b) APS’s 29.1% ownership in Palo Verde includes leased interests and is the largest capacity interest of all the participants.

See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Generation Facilities — Nuclear” in Item 1 for details regarding leased interests in Palo Verde.

See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Generation Facilities — Nuclear” in Part I, Item 1 for details regarding leased interests in Palo Verde.

The other participants are Salt River Project, SCE, El Paso Electric Company, Public Service Company of New Mexico, Southern California Public Power Authority, and Los Angeles Department of Water and Power.

1 unchanged sentence

The plant is operated by APS.

(d) See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Energy Storage” above for details related to APS’s energy storage facilities and agreements.

See “Business of Arizona Public Service Company — Environmental Matters” in Item 1 with respect to matters having a possible impact on the operation of certain of APS’s generating facilities.

See “Business of Arizona Public Service Company” in Item 1 for a map detailing the location of APS’s major power plants and principal transmission lines.

Energy Storage Facilities

APS’s portfolio of owned energy storage facilities in commercial operation as of the date of this report is provided in the table below.

Capacity amounts are approximate and represent the maximum designed MW the site can provide for three hours, unless noted otherwise.

Location Owned

Paloma Gila Bend, AZ 17

Cotton Center Gila Bend, AZ 17

Hyder I Hyder, AZ 16

Chino Valley (a) Chino Valley, AZ 19

Hyder II Hyder, AZ 14

Foothills Yuma, AZ 35

Gila Bend Gila Bend, AZ 32

Desert Star Buckeye, AZ 10

Red Rock (a) Red Rock, AZ 41

Total Energy Storage 201

(a) Capacity amounts represent the maximum designed MW the site can provide for four hours.

See “Business of Arizona Public Service Company” in Part I, Item 1 for a map detailing the location of APS’s major power plants and principal transmission lines.

Transmission and Distribution Facilities

20 unchanged sentences

Kyrene — Knox System 50.0 %

Agua Fria Switchyard 10.0 %

Each year, APS prepares and files with the ACC a Ten-Year Transmission Plan.

In APS’s 2025 Ten-Year Plan, APS projects it will develop 184 miles of new transmission lines over the next 10 years.

Additionally, APS plans to upgrade 687 miles of existing transmission lines over the same

The 2025 Ten-Year Plan includes a 28-mile 500kV line from the Jojoba substation to the Rudd substation.

The purpose of this 500kV line project is to bring in a new source to the west and southwest parts of the Phoenix metropolitan area which is experiencing rapid economic development.

This new source will provide customers in the area greater access to a diverse mix of resources from around the region.

Additionally, the 2025 Ten-Year Plan includes the rebuild of both Four Corners to Pinnacle Peak 345kV lines which span 289 miles each.

This rebuild will replace aging towers to ensure continued reliability and safety, increase important capability to the Metro Phoenix area, and improve access to a diverse mix of resources from the Four Corners region throughout the Southwest.

The 2025 Ten-Year Plan includes numerous projects with the purpose to interconnect new renewable energy resources to the transmission system.

In APS’s 2026 Ten-Year Transmission Plan, APS projects it will develop 263 miles of new transmission lines over the next 10 years.

Additionally, APS plans to upgrade 725 miles of existing transmission lines over the same horizon.

The 2026 Ten-Year Plan includes critical transmission projects that represent significant upgrades to our transmission system.

These upgrade projects, along with other projects included in the 2026 Ten Year Transmission Plan, are designed to support growing energy needs, strengthen reliability, and allow for the connection of new resources.

Plant and Transmission Line Leases and Rights-of-Way on Indian Lands

1 unchanged sentence

The Navajo Plant ceased operations in November 2019.

The co-owners and the Navajo Nation executed a lease extension on November 29, 2017, that allows for decommissioning activities to begin after the plant ceased operations.

The co-owners and the Navajo Nation executed a lease extension on November 29, 2017, that allowed for decommissioning activities to begin after the plant ceased operations.

APS, on behalf of the Four Corners participants, negotiated amendments to the Four Corners facility lease with the Navajo Nation, which extends the Four Corners leasehold interest from 2016 to 2041.

See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Generation Facilities — Coal-Fueled Generating Facilities — Four Corners” in Item 1 for additional information about the Four Corners right-of-way and lease matters.

Certain portions of our transmission lines are located on Indian lands pursuant to rights-of-way that are effective for specified periods.

Some of these rights-of-way have expired and our renewal applications have not yet been acted upon by the appropriate Indian tribes or federal agencies.

See “Business of Arizona Public Service Company — Energy Sources and Resource Planning — Generation Facilities — Coal-Fueled Generating Facilities — Four Corners” in Part I, Item 1 for additional information about the Four Corners right-of-way and lease matters.

Certain portions of APS’s transmission lines are located on Indian lands pursuant to rights-of-way that are effective for specified periods.

Some of these rights-of-way have expired and renewal applications have not yet been acted upon by the appropriate Indian tribes or federal agencies.

Other rights expire at various times in the future and renewal action by the applicable tribe or federal agencies will be required at that time.

In recent negotiations, certain of the affected Indian tribes have required payments substantially in excess of amounts that we have paid in the past for such rights-of-way.

The ultimate cost of renewal of certain of the rights-of-way for our transmission lines is therefore uncertain.

In recent negotiations, certain of the affected Indian tribes have required payments substantially in excess of historical amounts paid in the past for such rights-of-way.

The ultimate cost of renewal of certain of the rights-of-way for transmission lines is therefore uncertain.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 2. Properties