SB 1309 Arizona Senate · 57th Legislature - First Regular Session

public utilities; electric grid improvements

SB 1309 requires Arizona's utility commission to ensure grid modifications can reliably meet summer and winter electricity demand while preventing non-weather-related outages and power quality issues. It mandates that the "generation resource mix" (the combination of energy sources like solar, gas, or nuclear) avoids service interruptions and power quality incidents. The bill also requires replacement power plants for retired facilities to provide equally "dispatchable load following generation" - meaning power sources that quickly adjust to changing electricity demand. The bill passed the legislature in April 2025 but was vetoed by the governor on April 18, 2025.

Bill status vetoed 4 of 5 stages cleared

Introduction

Jan 2025

Committee Review

Mar 2025

Senate Passage

Apr 2025

House Passage

Mar 2025

Vetoed

Apr 2025

Introduced Jan 30, 2025 Vetoed Apr 18, 2025

Maddy AI version diff · 2 comparisons

What changed between versions

House Engrossed Version → Senate Engrossed Version · 4 edits · Apr 15, 2025

MODERATE

The bill was amended to clarify requirements for electric power grid modifications and the replacement of retired generation plants. The Senate version adds specific definitions for 'dispatchable load following generation' and 'generation resource mix,' and changes the reliability standard from a general requirement to produce enough electricity throughout the year to a more specific mandate to meet summer and winter demand. It also shifts the focus for replacement plants from ensuring equal or more reliable service to requiring equally dispatchable load-following generation.

Scope change

The bill's scope was expanded to include new definitions for key terms and more specific performance standards for electric generation plants, particularly regarding seasonal demand and the type of generation required when replacing retired plants.

DEFINITION

Added new definitions for 'dispatchable load following generation' and 'generation resource mix' to clarify what types of power sources and combinations are acceptable.

REQUIREMENT

Changed the requirement for grid modifications from a general standard of providing safe, adequate, and reliable service throughout the year to a specific mandate to meet demand during summer and winter months.

Modified the requirement for replacement generation plants from ensuring equal or more reliable service to requiring equally dispatchable load-following generation capabilities.

Added new criteria for generation resource mix that must avoid nonmomentary electric service interruptions unrelated to severe weather and power quality incidents.

Floor votes · House Mar 31, 2025

How they voted

This bill passed the Senate by voice vote (no roll call recorded).

Full legislative history

Actions timeline

Total actions

Key actions

Committee

Amendments

Apr 18, 2025

Vetoed

Vetoed by Governor

executive

Apr 15, 2025

Upper · Passed

PASSED

upper

Mar 31, 2025

Lower · Passed

PASSED

lower

Mar 19, 2025

Lower · Passed

DPA

lower

Mar 11, 2025

Lower · Passed

lower

Feb 26, 2025

Upper · Passed

PASSED

upper

Feb 25, 2025

Upper · Passed

upper

Feb 11, 2025

Upper · Passed

upper

1 primary · 1 co-sponsor