Arizona is one of the highest-value solar markets in the United States by potential, driven by abundant sunshine (among the highest solar irradiance in the country), rapid population growth particularly in the Phoenix metro, favorable climate for PV production, and increasing residential and commercial solar adoption. Solar panels in Arizona have scaled significantly across residential rooftops, commercial buildings, and utility-scale solar farms. But installing solar panels in Arizona requires understanding a utility landscape divided among two major utilities in different territories, several smaller utilities and cooperatives, and specific design considerations driven by extreme summer heat. This guide walks solar EPCs, installers, developers, and property owners through the Arizona solar market landscape.
Arizona solar market context
Solar energy in Arizona has grown substantially over the past decade, driven by multiple factors:
- Among the highest solar irradiance in the United States, producing more kWh per installed kW than most other states
- Rapid population growth in the Phoenix metropolitan area (one of the fastest-growing US metros)
- High summer electricity demand from air conditioning creating strong solar-friendly load profiles
- Substantial utility-scale solar development across the state driven by favorable land and irradiance economics
- Growing commercial and industrial rooftop solar segment
- Federal Investment Tax Credit supporting residential and commercial project economics
Solar companies operating in Arizona serve residential, commercial, industrial, and utility-scale segments, though Phoenix metro concentrates the majority of distributed solar activity.
Arizona utility landscape
Solar interconnection in Arizona flows through several distribution utilities with distinctly different territories, structures, and policies:
- Arizona Public Service (APS): the largest investor-owned electric utility in Arizona, serving most of the state including parts of the Phoenix metro (Chandler, Gilbert, Peoria, Surprise, and portions of Phoenix itself), plus territories across northern Arizona, western Arizona, and elsewhere. APS is regulated by the Arizona Corporation Commission (ACC).
- Salt River Project (SRP): a political subdivision of the state (not an investor-owned utility, not regulated by the ACC), serving central Arizona including a substantial portion of the Phoenix metro (Tempe, Mesa, Scottsdale, portions of Phoenix, and other areas). SRP has its own solar programs, interconnection processes, and rate structures.
- Tucson Electric Power (TEP): serves the Tucson metropolitan area and surrounding Southern Arizona.
- UniSource Energy Services (UES): serves specific areas of northern and southern Arizona.
- Rural electric cooperatives serving various rural Arizona territories
The APS vs SRP distinction is particularly important in the Phoenix metro. Two adjacent homes on the same street can be served by different utilities with completely different solar programs and interconnection processes. Solar EPCs must identify the correct utility for each project address.
Solar programs and rate structures
Solar programs and rate structures vary significantly between Arizona utilities:
APS solar programs
APS solar customers participate under specific solar tariffs approved by the Arizona Corporation Commission. Tariffs have evolved over time; current tariff structures for new solar customers should be verified directly with APS or the ACC. Historically, tariff changes have significantly affected solar economics for new APS customers.
SRP solar programs
SRP as a political subdivision sets its own solar programs and rate structures independently of the ACC. SRP has offered various solar programs over the years with distinct compensation structures for new solar customers. Current SRP solar programs should be verified directly with SRP.
TEP and other utilities
TEP and other Arizona utilities have their own solar programs with distinct compensation structures. Program terms have evolved over time and current program status should be verified with the specific utility.
Solar panels Arizona: design considerations
Installing solar panels in Arizona requires design attention to extreme conditions that differentiate Arizona from most other US solar markets:
Extreme summer heat
Phoenix and other lowland Arizona locations experience summer ambient temperatures regularly exceeding 110 F (43 C) with rooftop temperatures substantially higher. Design implications include:
- Aggressive conductor derating for ambient temperature per NEC 310.15 and manufacturer specifications
- Equipment operating temperature margins verified against manufacturer ratings
- Consideration for module operating temperature reducing output during peak heat
- Roof surface temperatures affecting inverter and combiner box siting decisions
- Attic and rooftop workspace safety considerations for installers
UV exposure
Intense UV exposure across Arizona affects material selection: UV-rated conductor jacketing, UV-rated racking coatings, and consideration of module encapsulant degradation over system lifetime.
Monsoon and wind considerations
Arizona monsoon storms bring dust, high winds, and occasional severe weather. Structural analysis must account for design wind conditions per ASCE 7-22 for the specific Arizona location.
Dust accumulation
Dust accumulation on modules affects long-term production. System designs may include consideration for periodic cleaning access.
Arizona building codes and electrical codes
Arizona jurisdictions adopt varying editions of the International Building Code, International Residential Code, and National Electrical Code with local amendments. Some Arizona jurisdictions have not adopted current code editions and enforce older editions. Always verify the currently enforced editions with the AHJ where the project is located.
PE stamping in Arizona
Commercial and larger residential solar projects in Arizona generally require Arizona-licensed Professional Engineer stamps. Smaller residential projects may not require PE stamping depending on the AHJ and project size. Structural PE stamp is required for structural analysis and racking design; electrical PE stamp is required for electrical design in many jurisdictions. Arizona Board of Technical Registration handles PE licensing.
Key Arizona solar AHJs
Arizona solar permit issuance is at the municipal level in incorporated cities and at the county level in unincorporated areas. Solar EPCs and installers should maintain AHJ-specific workflows for their most active jurisdictions:
- City of Phoenix Development Services Department
- City of Tucson Development Services
- City of Mesa Development Services
- City of Chandler Development Services
- City of Scottsdale Planning and Development
- City of Tempe Community Development
- City of Glendale Development Services
- City of Gilbert Development Services
- Maricopa County (unincorporated areas)
- Pima County (unincorporated areas)
Utility-scale solar in Arizona
Arizona hosts substantial utility-scale solar capacity driven by favorable irradiance and land economics. Utility-scale solar concentrates in areas outside major metro centers where large land parcels are available. APS and SRP procure utility-scale solar through various power purchase agreements and other structures. Utility-scale solar EPCs and developers actively deploy in Arizona.
Solar energy in Arizona: incentives
Solar customers in Arizona benefit from:
- Federal Investment Tax Credit (ITC) at 30 percent for qualifying residential and commercial projects
- Arizona sales tax exemption on solar equipment for residential customers
- Arizona property tax exemption for the added value of residential solar
- Utility-specific rebates and programs where offered
State-level Arizona solar tax credits and rebates have been reduced or eliminated over time as the market has matured. Federal ITC and property/sales tax exemptions remain the primary state-level incentive framework.
Common Arizona solar permit rejection reasons
- Conductor sizing not adjusted for Arizona ambient temperature derating
- Structural analysis inadequate for local wind conditions
- Utility SLD format not matching APS or SRP conventions (submitting APS format to SRP or vice versa is a common error in Phoenix metro projects)
- PE stamping missing where required (must be Arizona-licensed)
- Fire code pathway and setback requirements not clearly documented
- Rapid shutdown boundary and initiation devices not correctly documented
- Equipment operating temperature ratings not verified for Arizona conditions
- Wrong AHJ format submitted (city plan set filed to county, or vice versa)
Where outsourced solar design fits into the Arizona market
The Arizona solar market rewards design teams with familiarity across the APS and SRP utility formats, extreme heat design considerations, and Phoenix metro's multi-jurisdictional AHJ patterns. Solar EPCs and installers benefit from outsourced design partners fluent in Arizona utility formats, Arizona structural and electrical design conditions, and Arizona municipal AHJ workflows.
RIH Engineering provides outsourced solar PV design for EPCs, installers, and developers operating across Arizona including Phoenix metro, Tucson metro, and utility-scale project locations. Our plan sets are prepared with Arizona utility-specific interconnection formats, extreme-heat design calculations, and formatted for each AHJ across the state. If you want to talk through how outsourced design fits your Arizona pipeline, get in touch.
Frequently asked questions
Which utilities serve Arizona for solar interconnection?
Arizona solar interconnects through Arizona Public Service (APS) for most of the state and parts of Phoenix metro, Salt River Project (SRP) for a substantial portion of Phoenix metro including Tempe, Mesa, and Scottsdale, Tucson Electric Power (TEP) for the Tucson area, UniSource Energy Services (UES) for specific territories, and various rural electric cooperatives. The APS vs SRP distinction is critical in Phoenix metro where adjacent homes may be on different utilities.
What is the difference between APS and SRP for solar customers?
APS is an investor-owned utility regulated by the Arizona Corporation Commission (ACC). SRP is a political subdivision of Arizona that sets its own solar programs and rate structures independently of the ACC. This means solar programs, compensation structures, and interconnection processes differ between APS and SRP even for adjacent properties in Phoenix metro. Solar EPCs must identify the correct utility for each project address.
How does Arizona extreme heat affect solar design?
Extreme summer heat in Arizona (regularly over 110 F ambient in Phoenix and lowland areas) requires aggressive conductor derating for ambient temperature per NEC 310.15, verification of equipment operating temperature margins, consideration of module operating temperature reducing output during peak heat, and rooftop workspace safety planning. UV exposure also affects material selection including UV-rated conductor jacketing and UV-rated racking coatings.
Do Arizona solar projects need PE stamps?
Commercial and larger residential solar projects in Arizona generally require Arizona-licensed Professional Engineer stamps. Smaller residential projects may not require PE stamping depending on the AHJ and project size. Structural PE stamp is required for structural analysis and racking design; electrical PE stamp is required for electrical design in many jurisdictions. Arizona Board of Technical Registration handles PE licensing.
Are there state-level solar incentives in Arizona?
Arizona solar customers benefit from the federal Investment Tax Credit (30 percent), Arizona sales tax exemption on solar equipment for residential customers, and Arizona property tax exemption for the added value of residential solar. State-level Arizona solar tax credits and rebates have been reduced or eliminated over time as the market has matured. Federal ITC and property/sales tax exemptions remain the primary state-level incentive framework.