APS Solar Programs and Rate Structures for Arizona Customers

Arizona Public Service (APS) operates as the state's largest electric utility, serving approximately 1.4 million customers across 11 of Arizona's 15 counties. This page documents APS-specific solar programs, rate plan structures, interconnection requirements, and billing mechanics that apply to residential and commercial customers with grid-tied photovoltaic systems. Understanding APS rate design is a prerequisite for accurately projecting solar economics within the APS service territory.

• Definition and Scope
• Core Mechanics or Structure
• Causal Relationships or Drivers
• Classification Boundaries
• Tradeoffs and Tensions
• Common Misconceptions
• Checklist or Steps
• Reference Table or Matrix

Definition and Scope

APS solar programs encompass the rate plans, export compensation mechanisms, interconnection standards, and demand management tools that govern how a customer's rooftop or ground-mounted photovoltaic system interacts with the APS grid. These programs are administered under tariffs filed with and approved by the Arizona Corporation Commission (ACC), the state's public utility regulator established under Article XV of the Arizona Constitution.

The scope of this page is limited to the APS service territory as mapped and filed with the ACC. It does not cover Salt River Project (SRP), Tucson Electric Power (TEP), or Arizona's rural electric cooperatives. For SRP-specific rate structures, see Salt River Project Solar Options and Rates. For a broader regulatory framework covering all Arizona utilities, see Regulatory Context for Arizona Solar Energy Systems.

APS programs do not apply to off-grid systems, to systems located outside APS certificated service territories, or to customers served under special contracts with municipal utilities. The ACC's jurisdiction over APS does not extend to federal installations or tribal utility authorities operating under separate agreements.

Core Mechanics or Structure

Net Metering and the Transition to Excess Generation Credits

APS transitioned away from traditional retail-rate net metering following ACC Docket No. E-01345A-16-0036, which established a new framework phasing in export compensation below the retail rate for new solar customers. Under the current structure, customers who install solar receive an Excess Generation Credit (EGC) for kilowatt-hours sent back to the grid, rather than a direct retail offset.

The EGC rate is set periodically by the ACC and has historically been lower than the retail energy rate. As of the ACC's determinations, the EGC is calculated based on a resource comparison proxy methodology rather than retail avoided cost, meaning solar export value is tied to the wholesale cost of equivalent generation resources rather than the full retail tariff rate.

Demand Charges and Time-of-Use Rate Plans

APS residential solar customers are required to enroll in a time-of-use (TOU) rate plan. The primary rate plans applicable to solar customers include:

• APS Saver Choice Plus — a TOU plan with an added demand charge component (measured in $/kW), where the demand charge is assessed based on the customer's peak 30-minute interval demand during on-peak hours.
• APS Saver Choice — a TOU plan without a separate demand charge, relying on energy (kWh) pricing differentiated by on-peak and off-peak periods.
• APS Saver Choice Max — a plan oriented toward customers with battery storage, featuring a higher differential between on-peak and off-peak energy rates.

On-peak hours for APS plans are typically defined as 3 PM to 8 PM on weekdays, excluding holidays, though exact hours are defined in the applicable tariff schedule and are subject to ACC approval. For a conceptual overview of how solar generation interacts with these periods, see How Arizona Solar Energy Systems Works: Conceptual Overview.

Interconnection Process

APS interconnection is governed by the ACC's Interconnection Standards and APS's filed interconnection tariff. Systems under 10 kilowatts (kW) AC capacity qualify for a simplified interconnection application track. Systems between 10 kW and 2 megawatts (MW) follow a more detailed review process including technical screens. The Arizona Utility Interconnection Process page covers submission requirements, timelines, and inspection coordination in detail.

Causal Relationships or Drivers

The structure of APS solar programs is driven by three primary regulatory and operational factors:

1. ACC Rate Cases and Docket Outcomes
APS rate design changes must be approved through formal ACC proceedings. The shift to TOU mandates for solar customers was driven by ACC findings that flat-rate net metering created cost-shifting between solar and non-solar customers — a conclusion reflected in ACC Decision No. 76295 and subsequent orders.

2. Grid Infrastructure Costs
Demand charges on solar rate plans are a direct result of APS's argument that peak demand events drive infrastructure investment regardless of a customer's average monthly consumption. A customer who exports energy midday but draws peak power during the 3–8 PM window creates grid capacity requirements that energy-only billing does not recover.

3. Solar Penetration Levels
As APS's interconnection queue grows, the ACC and APS have adjusted export compensation downward to reflect declining incremental value of solar at higher penetration levels. The resource comparison proxy methodology explicitly ties EGC rates to modeled system conditions. For more on how solar irradiance patterns affect generation timing, see Solar Irradiance and Sun Hours in Arizona.

Classification Boundaries

APS solar customers fall into distinct program categories based on system size, customer class, and installation date:

Customers who interconnected before the ACC's 2017 rate restructuring were grandfathered under legacy net metering terms for a defined period per ACC order. New customers do not qualify for grandfathered terms regardless of system design. For distinctions between residential and commercial solar arrangements, see Residential Solar vs. Commercial Solar Arizona.

Tradeoffs and Tensions

Export Value vs. Self-Consumption
Under the EGC structure, each kilowatt-hour consumed directly from rooftop solar is worth the full avoided retail rate, while each kilowatt-hour exported earns only the lower EGC rate. This creates a strong economic incentive to size systems for self-consumption rather than maximum generation — a fundamentally different optimization than under traditional net metering. Battery storage becomes economically relevant precisely because it shifts export to self-consumption, which is documented in the Arizona Solar Battery Storage Overview.

Demand Charges and System Sizing
On the Saver Choice Plus plan, a customer's demand charge is determined by their single highest 30-minute interval during on-peak hours. A solar system does not reduce this charge unless it can guarantee generation exactly at the moment of peak demand — which conflicts with the 3–8 PM on-peak window occurring after peak solar production hours in Arizona summers. This misalignment means larger solar arrays do not proportionally reduce demand charges.

Rate Plan Selection Complexity
No single APS solar rate plan is optimal for all consumption patterns. High daytime-use customers may benefit from demand-free TOU plans, while high evening-use customers face compounding charges under plans that impose demand fees. The Arizona Corporation Commission requires APS to provide customers with bill impact disclosures, but the complexity of demand charge mathematics creates genuine informational barriers.

Common Misconceptions

Misconception: Solar eliminates the APS bill entirely under net metering.
APS no longer offers retail-rate net metering to new customers. Even customers who generate more electricity than they consume annually receive only the EGC rate for exported kilowatt-hours, which is less than the retail rate they pay for consumption. A fixed monthly customer charge also applies regardless of generation levels.

Misconception: A larger solar system always produces more savings under APS rates.
System oversizing can increase export without increasing savings proportionally, since exported energy earns the lower EGC rate. Under demand-charge plans, oversizing a system without addressing peak demand timing does not reduce the demand charge component. Arizona Solar Energy System Sizing Concepts covers this optimization problem in technical detail.

Misconception: APS interconnection approval is the same as a building permit.
APS interconnection authorization is a utility-level approval confirming that a system meets grid connection requirements. It is separate from and does not substitute for municipal or county building permits, electrical permits, or fire department inspections required under applicable building codes. See Arizona Solar Installation Timeline: What to Expect for a sequenced view of these parallel processes.

Misconception: The Excess Generation Credit rate is stable year to year.
EGC rates are subject to ACC review and can change. Rates set at the time of interconnection may not remain constant over a system's 25-year operational life. ACC dockets governing APS rate cases are publicly accessible at the ACC eDocket portal.

Checklist or Steps

The following sequence describes the structural phases a new APS customer with a solar system moves through, based on APS filed interconnection procedures and ACC requirements:

1. Confirm APS Service Territory — Verify the property falls within APS's certificated service area before any design work begins. APS territory maps are available through the ACC's certificated territory filings.
2. Submit Interconnection Application — Complete APS's online interconnection application with system specifications (inverter type, AC capacity, single-line diagram). Applications under 10 kW AC use the simplified track.
3. Receive Conditional Approval — APS issues a conditional interconnection approval, typically before installation, confirming the proposed system meets technical requirements.
4. Obtain Building and Electrical Permits — Secure applicable permits from the local authority having jurisdiction (AHJ), which may be a city, county, or town building department. This step is independent of APS approval.
5. Complete Installation — Installation must conform to the National Electrical Code (NEC), Arizona fire code setback requirements, and APS interconnection technical specifications.
6. Pass Inspections — Local AHJ inspection and, in some cases, APS field verification must be completed and documented.
7. Submit Permission to Operate (PTO) Request — After inspection sign-off, submit final documentation to APS requesting Permission to Operate.
8. Receive PTO and Select Rate Plan — APS issues PTO and the customer is enrolled in an eligible solar rate plan. Rate plan selection occurs at this stage.
9. Enroll in Monitoring (Optional) — Customers may enroll in APS's online portal for consumption and generation tracking. See Arizona Solar Energy System Monitoring Concepts for broader monitoring options.

For context on the full Arizona solar landscape accessible from the Arizona Solar Authority home page, this checklist represents only the APS-specific portion of a broader installation and regulatory process.

Reference Table or Matrix

APS Residential Solar Rate Plan Comparison

EGC = Excess Generation Credit, set by ACC order and subject to revision.

References

• Arizona Corporation Commission (ACC) — State regulator with jurisdiction over APS rates, interconnection standards, and solar program approvals.
• ACC eDocket Portal — Public access to APS rate case filings, docket records, and ACC decisions including Decision No. 76295 and Docket No. E-01345A-16-0036.
• Arizona Public Service (APS) — Tariff Schedules — Filed rate plan documents and interconnection application portal.
• Federal Energy Regulatory Commission (FERC) — Federal authority over wholesale electricity markets; APS retail rates fall under ACC jurisdiction, but FERC rules govern wholesale export compensation methodologies.
• National Electrical Code (NEC), NFPA 70 — The electrical installation standard referenced in APS interconnection technical requirements and Arizona building codes.
• Arizona Revised Statutes, Title 40 (Public Utilities) — Statutory framework governing ACC authority over APS and utility solar program requirements.