Recent Updates

The following items have been recently added or updated:

Energy vs. Agriculture in Italy

Electrification of transportation sector = More Renewable Energy Needed

Tucson Electric Power (TEP) to provide 70% of its energy from solar and wind by 2035

A link to a good article on What You Need to Know to make Sure Your Solar Rooftop is Properly Valued at Time of Sale: Is Solar Sexy When You Sell Your Home?

APS- Residential Battery Pilot Program

  • New Discovery Could Improve Organic Solar Cell Performance

    While there is a growing market for organic solar cells ­­– they contain materials that are cheaper, more abundant, and more environmentally friendly than those used in typical solar panels – they also tend to be less efficient in converting sunlight to electricity than conventional solar cells. Now, scientists who are members of the Center for Computational Study of Excited-State Phenomena in Energy Materials (C2SEPEM) a new Read More
  • Know Your Rights

    Arizona law protects individual homeowners’ private property rights to solar access by dissolving any local covenant, restriction or condition attached to a property deed that restricts the use of solar energy. This law sustained a legal challenge in 2000. A Maricopa County Superior Court judge ruled in favor of homeowners in a lawsuit filed by their homeowners association seeking to force the homeowners to remove Read More
  • Home Battery Systems

    Rooftop solar panels are common in Arizona thanks to abundant sunshine, but to get even more use from the technology, homeowners are beginning to pair them with large home batteries. Batteries allow homeowners to store their surplus electricity, rather than send it to the grid in exchange for credit from their electric company. Read More
  • Solar Hot Water

    There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don't. The typical solar water heater is comprised of solar collectors and a well-insulated storage tank. The solar collector is a network of pipes that gathers the sun's energy, transforms its radiation into heat, and then transfers that heat to either water or a heat-transfer fluid. Read More
  • Federal Residential Renewable Energy Tax Credit

    (Information provided by DSIRE - Last reviewed 02/19/2009) The information below is somewhat dated, the incentives have been extended, but reduced.  See our more up to date article. Incentive Type:   Personal Tax Credit State:   Federal Eligible Renewable/Other Technologies:   Solar Water Heat, Photovoltaics, Wind, Fuel Cells, Geothermal Heat Pumps, Other Solar Electric Technologies Applicable Sectors:   Residential Amount:   26% Maximum Incentive:   Solar-electric systems Read More
  • Solar Building Design in Arizona

    The idea of using the sun to meet the energy needs in our buildings has been with us since the time of the Greeks, with some of the design manifestations even evident in the prehistoric structures of Arizona and the Southwest. There is a great historic tradition for Arizona buildings that utilize our most abundant resource, and the current increases in The idea of using Read More
  • How Not to- Battery Connections

    Photo shows the situation after a battery discharge test at 300 amps was terminated on a 1530 AH IBE battery string when one post melted. During the discharge test all cell voltages are logged. The sum of the cell voltages was 2.73 volts lower than the 48-volt string voltage. This is an average of 118 mv per inter-cell connection, 5-10 mv is the normal range Read More
  • 1 New Discovery Could Improve Organic Solar Cell Performance
  • 2 Know Your Rights
  • 3 Home Battery Systems
  • 4 Solar Hot Water
  • 5 Federal Residential Renewable Energy Tax Credit
  • 6 Solar Building Design in Arizona
  • 7 How Not to- Battery Connections


  1. Solar Center Blog
Brian Czech
17 February 2019

What’s Really Green and What’s Really New

Ask Americans what the Green New Deal is all about, and you’ll get two basic answers. Most often you’ll hear, “It’s about moving to renewable energy in order to fight climate change.” You’ll also hear, from a camp further right, “It’s all about socialism!”

Lucy Mason
06 January 2018

Wishing you a wonderful and Happy New Year!

The year 2017 has gone by quickly, and AriSEIA has accomplished a full and active agenda to further solar and renewable energy in Arizona. 


No result.

Featured (Note- Articles below shift Left-Right)

Some things to pay attention to in Arizona

Arizona Legislature 

The Arizona Legislature's session had many energy bills to oppose (HB2248, SB1175, HB2737 in particular).  These died at the end of the session, but the concepts could be presented in the future.

Status of 2021 Session Bills:
DEAD-HB 2248: Corporation Commission; Electric Generation Resources
Alarm bells are ringing by environmentalists over HB2248 (and Senate bill 1175). These would prohibit “Arizona Corporation Commission from adopting or enforcing any policy, decision or rule that directly or indirectly regulates critical electric generation resources used or acquired by public service corporations within Arizona’s energy grid without express legislative authorization. (Sec. 1) 2.” The bill cripples the ACC from doing its job. (Kerr, Gowan, Gray and others). The House passed a Senate committee 6-4 but was caught up in committee when the Legislature adjourned.

DEAD-SB 1175: Corporation Commission; Electric Generation Resources
See above.

DEAD-HB 2737: Corporation Commission Actions; Investigation
Dead. Environment – HB2737, would allow any lawmaker to order Arizona’s Attorney General to investigate the Arizona Corporation Commission and to require 10% of the commission’s operating budget to be withheld if the AZ Supreme Court determines this agency has exceeded its statutory authority or is not executing or enforcing statute. Sponsored by Jacqueline Parker (R-16). Probably aimed at curbing the ACC environmental regulations. Passed Committee of the Whole but not voted on in time.

Thanks to all who voiced their opposition to the above bills. It is imperative that we convey the negative impact passing bills such as these will have on the regulatory certainty that companies rely on to locate, relocate and grow. We need to protect our state’s economy, our health and our future. Email your representatives.

Here is a link to find your representatives


Arizona Corporation Commission 

PHOENIX – The Arizona Corporation Commission will be holding two telephonic oral proceedings next week to solicit public comment on its proposed Energy Rules. The telephonic oral proceedings will be held on Monday August 16 and Thursday August 19 at 10 a.m. Written public comments can be filed into the docket until August 20, 2021.

At a May 26, 2021 Special Open Meeting the Corporation Commission voted 3-2 to advance an amended package of Energy Rules. Due to the substantive changes made by various amendments, the rules are now moving through a supplemental rulemaking process which provides for additional public comment opportunities. Commission Utilities Division Staff will then file a response to comments received and a revised Economic Impact Statement by September 20, 2021. Following the Staff Report, an Administrative Law Judge will prepare a new Recommended Opinion and Order which will come back before the Commission for a final vote sometime this fall.

To participate in the oral proceedings, dial 1-888-450-5996, to speak use passcode 457395#, and to listen only use passcode 4208475#. You may file written comments into docket number RU-00000A-18-0284. To watch live visit

On August 12, 2021 the Office of Arizona Corporation Commission Chairwoman Lea Márquez Peterson released an interesting summary of the average future bill impact to residential customers  up to 2050, depending on the utility and the amount of emission reductions that each utility achieves within that time.  Worth a read.

PHOENIX - Several clean energy proposals are currently pending before the Arizona Corporation Commission. After several months, the Commission has received an independent analysis of at least two of these proposals: 100 percent zero-emission energy by 2050 and 80 percent clean energy by 2050. 

Link to the full summary

On May 26th 2021, the Arizona Corporation Commission reconsidered and passed a Clean Energy Rules package. The energy rules package includes 100% carbon-free energy in Arizona by 2070. And the carbon reductions are requirements and not goals.

Revised carbon emissions reductions levels by the following:
• 50% by December 31, 2032
• 65% by December 31, 2040
• 80% by December 31, 2050
• 95% by December 31, 2060
• 100% by December 31, 2070

Most importantly, the passed rules retained all the beneficial policies and requirements around storage and distributed storage. Specifically, the rules include a 35% energy efficiency requirement, which is the nation’s first distributed storage/solar requirement, preferential treatment for energy procurement from coal-impacted communities and tribes, as well as a complete rewrite of the IRP rules that will require the Commission to approve, rather than acknowledge a preferred portfolio of resources.

This is not yet final, as a result of substantive changes made to the original Recommended Opinion and Order, the amended energy rules package will be sent back through the formal rulemaking process. An updated schedule will be implemented that will allow for written comments and public comment on the record. Interested parties can submit formal written comments to the docket beginning July 9, 2021 through August 20, 2021. Public comment sessions will be held on August 16 and 19, 2021, at 10am.

The passage of the Energy Rules as they presently stand reflects a significant win for ratepayers, for the people of Arizona and for the Solar Energy Industry.

See also Materials Presented by the Joint Stakeholders at the Commission's March 2020 Energy Rules Workshop

The Nature Conservancy has submitted their report "Arizona Thrives - A Path to a Healthy and Prosperous Future" to the ACC. Interesting.

APS has submitted their report,  The Solar Center has slightly reformatted this report by rotating the pages for easier viewing.  APS has provided two presentations to address the ACC questions. Worth a read.

Update July 30, 2020: 

When the Arizona utility regulators met to decide these issues they deadlocked over whether they should increase the state's requirements for renewable energy. It proved not possible to obtain the agreement of at least three commissioners, the meeting was adjourned.

See the Arizona Republic article on this:  Arizona utility regulators hit roadblock on clean-energy rules, abruptly end meeting.

The Arizona Corporation Commission (ACC) has released the Notice of Final Rulemaking Interconnection of Distributed Generation FacilitiesInterconnection of Distributed Generation Facilities document.

With this rulemaking, the Commission adds a new Article 26, entitled " Interconnection. of Distributed Generation Facilities" to 14 A.A.C. 2, the Chapter containing the Commission's rules for fixed utilities, with the new Article 26 including 28 new rules. The rules for Interconnection of Distributed Generation Facilities ("DGI Rules") establish mandatory technical standards, processes, and timelines for utilities to use for· interconnection and parallel operation of different types of distributed generation ("DG") facilities; customer and utility rights and responsibilities; provisions for disconnection of DG facilities from the distribution system; specific safety requirements; more flexible standards for electric cooperatives; a reporting requirement; and a requirement for each utility to create, submit for initial approval and submit for approval periodically and when revised, and implement and comply with a Commission-approved Interconnection Manual.

The first dozen pages are basically legal stuff.  The document defines how an utility must review, then accept/reject/etc. an application to connect distributed generation to the utility.  It defines both customer rights and utility procedures.  There are a lot of utility, installer and customer comments along with the ACC staff recomendations. 

 Municipality Info


PhoenixFireLogo sm

The City of Phoenix is now (January 2020) requiring a special permit from the Fire Department for most solar systems and batteries.  The fees and required plans varies with size and content.  See this link for an application and details: Photovoltaic OTC Bundle Rev 01-2020.pdf

This is in addition to a building permit from the Planning & Development Department and must be separately obtained at a different address (150 South 12th Street) or on-line via the above link. Also noted is that residential PV permits are no longer over the counter and as of March 2020 are estimated to take 29 working days to process.  Separate inspections are required.

The code requirements are contained in Phoenix-Chapter 12 BESS R-3-1.pdf

Also note: All Phoenix solar building permits are now electronic submittal only. Contact the Electronic Plan Review (EPR) Triage Team at 602-534-5933 or For more information on EPR, visit us at

Related: PV Rapid Shutdown Signage- Phoenix


 At the Federal Level

New information coming soon 

Utility Information

Arizona Public Service Co. has announced that it plans tintroduce a Residential Battery Pilot Program.

The pilot will be available to APS residential customers who install residential battery systems, enroll in a TOU (Time of Use) or TOU-plus-demand service plan and commit to discharging their batteries during on-peak periods. (Note: Rate requirements are waived for customers on grandfathered solar rates.) The pilot will help APS learn about battery performance in a variety of conditions and how batteries may create value for customers through improved management of energy demand at their residence and help reduce stress on the electric grid.

Full Article

Arizona Public Service Co. has announced that it plans to produce all of its electricity from carbon-free sources by 2050 and will get 45% of its power from renewable sources like solar and wind by the end of this decade.

This is a good improvement from the point of view of sustainable energy.  There are still a lot of details to be worked out such as the role that distributed energy will take.  Will APS APS improve its policies in regard to residential and small commercial systems.

There are several good news articles and the APS press releases on this announcement:

APS:APS sets course for 100 percent clean energy future

Arizona Republic: APS will eliminate carbon emissions by 2050 and close coal plant ahead of schedule, CEO says

The Washington Post: Arizona’s biggest utility says it will get all of its electricity from carbon-free sources by 2050


Tucson Electric Power (TEP) plans to provide more than 70 percent of its power from wind and solar resources as part of a cleaner energy portfolio that will reduce carbon emissions 80 percent by 2035.

TEP has filed its integrated resource plan (IRP) with the Arizona Corporation Commission, outlining plans for 2.5GW of new solar and wind over the next 15 years and 1.4GW of energy storage capacity as it progressively shutters its coal power stations.

See the TEP Press Release for more information:

TEP customers intending to install a new PV system now need to check that their system can be safely installed and connected to TEP’s grid.

TEP now has service areas that are saturated with PV systems where new PV systems are subject to additional review and requirements under Arizona’s Distributed Generation Interconnection Rules. TEP has prepared DG Saturation Maps showing these areas.

This further described at

This requirement stems from the recent Distributed Generation Interconnection Rules issued by the Arizona Corporation Commission.

Further information is available at:Interconnection of Distributed Generation Facilities

Update: See the related article on New state rules limit rooftop solar systems in some Tucson neighborhoods




Interesting Technology Updates;





Other Announcements

Interesting Videos

Understanding your APS Connected Photovoltaic System- Net Metering

If you have a photovoltaic (PV) system connected to APS and do not have other monitoring of the PV system such as that provided by most inverter manufacturers, it is not easy to determine the solar production that corresponds with the monthly electric bill.  APS requires a solar production meter and this data is recorded and made available to the customer, but with a little difficulty.  The following example is based on the now grandfathered 'Net Metering' (rate rider EPR-6) wherein any excess PV production, measured in kilowatt-hours (kWh) is used to offset energy delivered by APS.  This method has been replaced by a system APS calls RCP, utility speak called 'Resource Comparison Proxy' (note that the APS website was developed by utility personnel using their view of the situation, not the customer view). The Solar Center intends to repeat the following procedure later with examples based on RCP.

Look at the recent example of an APS electric bill and see if you can determine the solar production:

APS web 6m

The APS bills show only that 186 kWh in this case was net metered.  The bill does not show the solar production that was directly used, to determine this one has to have an APS web account (free) and has to go online to learn more. There is a lot of data available.  Note the 'Meter reading' dates above, this will be used later to calculate the solar production. Using a browser such as you are using to view this article, go to

There is presently a Capcha screen to prove that a person and not an automated computer is accessing the website.  Enter the requested data.  

APS web 1b

Enter your APS username/password then click login.  If you do not already have a username and password, click on 'register'. The following is typical.

APS web 1

Next select 'daily and hourly usage'.  Solar production is a subset of usage for some APS reason.

APS web 1a

There are four types of data available and a calendar to select the dates to view.  See the red instructions in the examples below.  In APS jargon 'received usage' is solar production. This screen shows the solar production graphically, good for seeing relative production that depends on the sunshine and to a lesser extent the air temperature. Clicking on the 'Day' tab will expand that day, otherwise a month (or the current month to date) is displayed.

APS web 2

This view shows the pattern of the energy drawn from APS.  Actual total usage at a specific time will be higher since PV system production will be used directly if there is enough usage at the specific instant.

APS web 3

 APS web 4

APS web 5

Note that on each of the above examples, there is a down arrow next to the 'for service at' section and that clicking on this down arrow shows a second service, the PV production Meter with an '*'. The address is blurred in this example. Select the line with the *.

APS web 11

The production data is displayed in two formats, a bar graph for the month, and a graphical format for the week.

Hal Jul 2019 PV

Hal Aug 2019 PV Hr

In order to get values for calculations, the monthly summary data needs to be downloaded as Excel files, usually for the two months that include the date range of the electric bill.  With the 'daily energy useage' tab selected, select the first month of the range (click on any date), then click on the 'download meter data' text link over the calendar.  This will download a file named 'Excel.xlsx' ( or Excel(y).xlsx where 'y' is a digit, added by your computer when 'Excel.xlsx' already exists).  A spreadsheet program is needed to open and view these files, Excel for example.  Select the 'daily energy usage' and 'delivered useage' tabs.  The Excel data will look like this:

APS web 8 The values for the billing date range, July 25 to August 23 in this example, need to be added.  This can be done with the spreadsheet program or manually.  In this example the sum is 711.5 kWh. This is not straight forward since the values shown are actually text and Excel can not directly add them.  Use the =value(cell) function in another column to convert the text to actual values.  Now that the actual solar production is known, the below  chart shows the relationship of these values.

APS web 9

The calculation of Home useage is (Solar Production) + (Purchased from APS) - (Sold or net metered to APS).


Arizona’s Salt River Project Utility Challenged On High Rooftop Solar Rates

In 2015 SRP became anti-solar when it adopted special solar rates (E27) with some high demand charges, etc.  SolarCity, later acquired by Tesla, challenged SRP’s discriminatory solar rates on antitrust grounds. SolarCity/Tesla took the case to the Supreme Court after a lower court rejected its request to dismiss the case. SRP reached a settlement with Tesla before the Supreme Court hearing, and the discriminatory fees were left in place. As part of the settlement SRP agreed to purchase a 25 megawatt/100 MW-hour battery energy storage system from Tesla. This meant that the basic reasons for the lawsuit, challenging the discriminatory rates, were not subject to court review and a chance to rule against SRP. The Center for Biological Diversity filed an Amicus brief against SRP’s motion to dismiss in order to have the Supreme Court consider the antitrust grounds.  

The SRP rates have been proven to stifle rooftop solar, reducing new installations in SRP service areas while installations in other areas of Arizona increased.  SolarCity claimed that SRP’s discriminatory solar rate structure is an obstacle to clean energy transition, because it undermines the value of homeowner investment in these systems. The solar rates were not examined by the courts, SRP basically claimed that it was exempt from regulation in this situation.

The Center for Biological Diversity is an Arizona-based non-profit environmental organization dedicated to the preservation, protection and restoration of biodiversity, ecosystems, and public health. On behalf of its more than 1.5 million members and online activists nationwide, including more than 890 members, and over 15,000 supporters, who live in SRP service territory, the Center advocates for a rapid transition to a clean and just energy system that optimizes renewable energy sources such as distributed solar in order to reduce U.S. greenhouse gas (“GHG”) emissions and combat climate change.

The Center filed an Amicus brief to present three discrete arguments against SRP’s motion to dismiss. First, SRP should not be permitted to rely on state action immunity to shield its discriminatory rate structure from antitrust liability, and certainly not at the pleading stage. Second, state-action immunity for utilities like SRP should in any event be constrained to open the door for distributed solar competition. And finally, SRP is violating the Equal Protection clause because its anti-solar electricity rates have no rational basis.

Charles W. Thurston has a good article on this subject in CleanTechnica:Arizona’s Salt River Project Utility Challenged On High Rooftop Solar Rates

Univ. of Arizona - Institute for Energy Solutions May 2019

Some interesting content from the May 2019 newsletter

UA Institute for Energy Solutions logo

June 7th
10 AM - Noon

Indige-FEWSS mobile water purification unit demonstration

Dr. Karletta Chief, Navajo Nation President, Jonathan Nez, Diné College President, Dr. Charles Roessel, and Diné College Students and Indige-FEWSS fellows will discuss and demo the water purification unit at Diné College, Tsaile Campus.

Water Purification UA

Imagine Adaptation | Finding Solutions fo the Food, Energy, Water, Nexus January 2019, British film company-One World Network, gathered UA researchers and community delegates to answer the question "What is being done to address the big issues at the energy, water, food nexus that will secure our world as we know it for the future?" Out of this exploratory emerged a documentary which takes a look at the many branches of UA's collaborative E-W-F research. We invite you to watch this exciting new video!

Path to Solar

NREL SRP Battery StudyDraft 7 11-26-19

The Arizona Solar Center is often asked the question “How do I find out if solar energy is the right choice for me now?” It seems like a simple question, but the answer really depends on the situation.

There are many ways to use solar energy on both personal and commercial levels. Some of the exciting possibilities for solar electric (photovoltaic or PV) power use are:


  • Highway, street, and sign lighting
  • Pool and home accent lighting (especially with the new high efficiency LED lights)
  • Signaling for railroad crossings
  • Gate openers
  • Power for forest or park lookout stations
  • Telemetry packages, instrumentation, weather, earthquake detectors and recorders
  • Power for control of valves in pipelines
  • Gas detection systems in refineries
  • Cathodic protection to prevent corrosion in pipelines, wells, bridges, etc.
  • Lighting in rural areas (restrooms in parks as an example)
  • Security for industrial buildings
  • Power for refrigerators, lights and communications in remote medical centers.
  • Power for water pumps -  commercial, domestic and livestock water, or swimming pools
  • RV power while parked
  • Attic ventilation
  • Security systems
  • Remote and on-grid home power systems

If the previously mentioned uses of lighting, communication, refrigeration, water pumping, etc. are combined into a single power system, renewable energy can be used to provide power for the basic needs of entire villages, encampments, and recreational areas which may be too far from power lines to ever have grid-supplied electricity.

Over the last decade it has become routine to have home solar electric systems that are connected directly to the local utility and operate without batteries. These are called grid-tied systems, and are the focus of most residential and commercial activity. In Arizona there are utility rebates (actually incentives to install, with the resulting environmental credits being assigned to the utilities) that offset a substantial portion of the costs of installing grid-tied PV systems. In some cases this can include domestic hot water systems. Refer to other parts of the Arizona Solar Center website for more information. There is also information here about tax credits and rebates.
To begin answering the question “How do I find out if solar energy is the right choice for me now?” please review the following Frequently Asked Questions. After understanding this basic information, please see our "Path to PV" below, which follows a typical but fictitious family on their journey of learning and finally making the decision to go solar.

Frequently Asked Questions- Is solar energy the right choice for me now?



Why should I be interested in solar?

  • I want to be more environmentally responsible, using sustainable resources
  • I want to lock in my cost of energy
  • I want to generate my own electricity
  • I want to make a profitable green investment



What alternatives should be considered?

  • Energy conservation- Invest in more efficient air conditioners, insulated windows, etc.
  • Conduct a home Energy Audit
  • Switch to efficient lighting such as LED bulbs




What are my solar objectives?
Some we have heard:

  • Contribute to the value of the house (tax free equity increase)
  • Make a good return on investment
  • Lock in some of my energy costs in an inflating economy
  • Take advantage of incentives, rebates, and tax credits
  • Get it right the first time
  • Do the best for my family



Do I have a good site for PV?

Your site must have clear, unobstructed access to the sun. Buildings, trees or other vegetation should not shade your site. South-facing roof exposure is best, but roofs facing east and west may be OK, there is a reduction in output - see Effect of PV Array Orientation - Phoenix AZ. If a rooftop is not available, your PV system can also be mounted on the ground.




Is solar for me?

Some points to consider:

  • Do I own my own home, or can the improvement be moved if necessary?
  • Do I have a suitable area for a solar system?
  • Do I have the cash or financing for the system?



How much mounting space do I need?

A small PV system can use as little as 50 square feet. A larger system, to meet the needs of a typical household, would use between 300 to 600 square feet. As a rule of thumb, 100 square feet of PV area produces 1 kilowatt of electricity.



What can I do as a homeowner?

  • Install a Domestic Hot Water (DHW) system
  • Install a grid-tied PV system <possible link that illustrates an example>
  • Install a non grid-tied PV system (attic fan, yard lights, shed power) <possible link>
  • Install a wind energy system (if the location is suitable)
  • Install skylights
  • Install solar pool heating
  • Install a PV Powered Pool Pump
  • Understand your energy usage by getting a summary from your utility (needed later to compare to system output estimates)



Are there any incentives and rebates available in Arizona?

In Arizona there are no longer any utility based incentives on solar systems. But there are Arizona and Federal tax credits and/or rebates that may apply to your situation. Renewable Energy Incentives

The following is specific to photovoltaic power systems



Why should I consider buying a PV system?

A PV system reduces or eliminates the amount of electricity you purchase from your utility or electric service provider. A PV system can be an excellent investment, save you money on your electricity bill and act as a hedge against future price increases.

The electricity generated by your PV system is clean, renewable and reliable. You help your community by reducing the load on the utility grid. You can provide additional electricity for the grid when you generate more than you use during the day, when electricity demand is highest.



How do I relate system size to energy produced?

You can match the size of your system to your electricity needs and budget. The average household in Arizona uses over 10,000 kilowatt-hours (kWh) per year. If your usage is typical of the average household, a system in the 5 to 8 kilowatt (kW) range would be adequate to meet most of your electricity needs. It is usually not advisable to displace your entire utility bill, since efficiency improvements and conservation could cause you to produce more energy than you use. Currently, utilities do not pay competitive rates for generation above annual usage. see Effect of PV Array Orientation - Phoenix AZ. and Considerations in sizing a PV system in Arizona



What do I need to know about connecting my PV system to the grid?

You will need to enter into an Interconnection Agreement with your utility. This agreement addresses the terms and conditions under which your system will be safely connected to the grid. The agreement also specifies the metering arrangements for any surplus electricity your system generates on the electric grid.

Excess electricity might be generated during the day when your system produces more electricity than you need. Your meter would simply run backwards to record the amount of electricity 'sold' to your utility. If you select a rate plan with Peak and Off-Peak periods, the utility will most likely account for the net metering by rate period. This is very utility specific, see the article Arizona Electric Utility Information.
Older PV systems may have qualified for net metering where in any excess production is banked with the utility for later use.



How can I estimate the best size system for my home or business?

To estimate the best system size for your home or business, please review our article on Considerations in sizing a PV system in Arizona.
There are ‘Solar calculators’ on the web. APS and SRP have links to calculators that will give ballpark cost and performance estimates. Use these with some common sense as they may not consider rate period and demand charge effects on the resulting savings.

There is also the NREL document:

If you want your PV system to meet half of your electricity needs, then you should size it to meet half of your annual electrical usage. Alternatively you can offset only a small portion of your electricity bill with a single PV panel.
First of all, do not install a system that produces more energy on an annual basis than you expect to use because the present utility tariffs generally have a low credit for the excess.
If in doubt, start small and ask the installer to plan for expansion in the future (i.e. install a larger inverter and conduits at little extra cost). However, check on your utility policy on this as any system size changes may cause loss of any favorable grandfathering of buy-back rates.



What does a typical PV grid-tied system look like?

  • Small home system <link>
  • Medium home system <link>
  • Large home system <link needed>



How much does a PV system cost?

Although many factors affect the cost, an average PV system costs from $2.50 to $4.50 a watt, including installation. This is about $10,000 to $18,000 for a 4 kW system.



Am I eligible for a rebate?

At present (2019) there are no incentive rebates. There are tax credits that may apply to your situation, see our article on Renewable Energy Incentives.



Are there any financing programs available?

The best way to finance a PV system for your home is through a mortgage loan, which includes a primary or secondary mortgage or home equity loan secured by your property. If mortgage financing is not available, look for other sources such as conventional bank loans. In August of 2008, APS announced a financing program for its customers who desired to finance systems installed under their incentive plans. A variety of “leasing” programs are becoming more common in the industry. The buyer is cautioned to do an in-depth financial analysis or consult a qualified party to determine the best approach for his or her system.



How do I find a PV retailer?

The Arizona Solar Energy Industries Association provides a list of PV retailers and installers. Retailers either can provide installation or can refer you to installation contractors in your area. Try to find a company located in the area where your system will be installed. Price is only one factor when selecting a PV company and/or contractor.

Here are some other considerations:

  • Does the company have experience installing grid-connected systems?
  • How many years has the company been in the business of installing PV systems?
  • Does the company use licensed Arizona contractors?
  • Does the company have any judgments or liens against it?
  • Will the company provide references from previous customers?
  • If you get more than one bid, make sure that the bids are for the same identical size system.



How do I know if I am being offered quality equipment?

Arizona law requires that PV modules be listed to UL1703, check the data sheet.

Inverters and charge controllers should be listed to UL1741.

PV installations are subject to the National Electrical Code and building permits. Check with your local building permit office to determine which version applies, there is no Arizona statewide policy in this area.

The Solar America Board for Codes and Standards (Solar ABCs) has some good information. See Solar America Board for Codes and Standards (Solar ABCs)




How does it work with my electric utility? How does the billing work? What if I sell the home?

This differs with the utility. Most utilities (e.g. APS, SRP, and TEP) have web sites that can help explain the procedures:(web links)

APS (see also Summary of Residential Rate Plans for APS Customers

See our article on Arizona Electric Utility Information for more specific information on utility policies.

Generally, the utility installs a bi-directional kilowatt-hour (KWh) revenue meter that measures power flow in both directions. The resulting bill will usually show how much energy you have used and how much you fed back to the utility. Any balance in your account should be listed for future use.

The utility usually requires the PV system installer to install a socket for a second KWh meter that measures the output of the inverter as well as a lockable disconnect switch in case the utility needs to work on the utility line nearby.



How do I operate the system?

Generally the systems operate automatically. They do have ON/OFF switches and a utility lockable disconnect switch. Most inverters have a digital display or indicators that show operation. The homeowner should be provided with an operations manual for the system by the installer.

Generally, the natural rain keeps the solar panels clean enough (without calcium deposits from tap water). If desired, they can be cleaned. A hose is usually suitable. Use caution, as this can be dangerous due to the height and a remote possibility of electrical shock.



What will it look like? Will it affect anything?

Most systems can be installed so that the owners are proud of their investment. <possible link>
Modern inverters must meet radio frequency non-interference specifications and as such should not interfere with radio and TV.



Can I monitor the system with my computer?

Most, but not all inverters are capable of sending data to a computer for monitoring. An accessory card may be needed. Consult the user manual or your installer for specifics.
Some inverter manufacturers offer web services if the home has internet access. Many homeowners have web pages on the manufacturer’s web site with photos, specifications, comments, and real-time performance data. 

The smart meters used now by APS and SRP (and perhaps other Arizona utilities) gather detailed data on the output of the installed PV system and make this information available to their customers. For example see this article on APS- Understanding your APS Connected Photovoltaic System



How long will it last? What is the warranty?

Modern systems are reliable and should last 10-25 years before any repair or replacement is needed.

  • Arizona law requires a full two-year warranty by the installer.
  • Most inverters have available extended warranties up to 10 years.
  • Most PV modules have a 20 or 25-year warranty.



Do I have a suitable roof or ground area?

Effect of shade on PV systems <possible link>
Roof requirements are discussed in the Solar ABCs guide to expedited permitting
What kind of roof can be used? PV mounting systems are compatible with all roof types including tile, shingle, metal and flat.



What about HOA Approval (when necessary)?

  • Always seek approval
  • State law protects your right to install
  • If you live in an area that is governed by a homeowners association, all improvements on your property must be submitted to the board or Architectural Review Committee for approval. Arizona law protects your right to install solar energy systems; in fact, the Arizona statutes are among the strongest in the nation. Your HOA cannot prevent you from installing your solar energy system, but they can have installation guidelines as long as those guidelines do not increase the cost of the system or decrease the performance or life of the system.
  • Just because the law is on your side, don't make the mistake of installing a solar energy system without approval from your HOA. Your contractor will provide you with the information that you will need to complete the HOA's application and can help you with the application process. If you encounter problems with your HOA, your contractor will also be able to give you advice on how to proceed to ensure that your HOA follows Arizona law and approves your application.



What about Building Permits?

  • Learn about city inspection & approval requirements
  • There is also utility inspection, approval and commissioning
  • Remember that a licensed contractor must do the installation of your solar energy system. Be sure to check out the record of the contractor who will be installing your system with the Arizona Registrar of Contractors (
  • Most utilities require a final inspection by the local jurisdiction before they will issue a check under their rebate programs.
  • The Solar America Board for Codes and Standards (Solar ABCs) has developed an expedited permit process for small PV systems. It contains a set of standardized application forms. publications/reports/expedited-permit/forms/index.html



How to decide on a company?

  • Look at all the factors involved.
  • Does the company have the experience and knowledge to make you feel comfortable?
  • Is the price reasonable?
  • Keep in mind that the lowest bid may “cut corners” and possibly come back with unexpected “adders” and shoddy workmanship. 



How to proceed?

See “A Path to PV,” below which follows a fictitious family through the process.


A Path to PV
One day, Sunny and Sam Brightly were driving about town when they saw a home with a large number of solar modules on the roof. It looked pretty expensive.
Later while watching tv, they saw an advertisement on a new financing plan being offered to help make the installation of solar systems more affordable. They remarked about it, but took no action at the time.
The following week their oldest child came home from school and told them how they had just learned about using sunshine to make electricity. He asked his parents, "Why don't we do something to use solar energy?" The parents said "Let's see what we can find out on the Internet." They searched "Solar Energy" and "Arizona." A top hit was the Arizona Solar Center, so they looked at it. There was a lot of information and various descriptions of programs, including a list of other organizations.
Since they had seen news about utility incentives and there were links from their utility’s webpage to solar programs, they followed a link to their utility's solar section and reviewed the basic steps.
Using their utility, the Arizona Solar Center, and other sources as references they decided to ask three different companies to make presentations and estimate the cost and performance of potential PV systems that would best fit their home.
The interactions with the prospective suppliers varied. Some asked if they already knew the size of the system they would be interested in, but the family wasn’t sure. Others asked about their local utility company, the kind of roof they had, or their typical summer electric bill.  One supplier requested that they ask their utility for a summary of their usage history (easy to get). The Brightly family had questions of their own such as “What will your system cost us after tax credits and how much will we save on our electric bill?”
All three suppliers visited the home, took measurements of the roof area, inspected the electrical service and decided on the best place for the inverters. Each approach was different; one supplier presented three basic standard kits with about a two to one range in costs and no specific options. Good looking literature, but only annual performance data.
Another supplier arrived with a copy of an aerial photo of the house (obtained from the web site) with an initial layout of an array of specific PV modules that seemed to fit well. There was a detailed quote for the illustrated layout and an offer that the size could be easily varied and a new quote printed out.
The third supplier came out, made measurements, asked some questions, answered many questions and later sent an estimate. A typical form used by suppliers to gather site data is included here as a reference. <link to be made>
All three suppliers were either Arizona licensed contractors or used a related contracting company for the installation. All asked about any Home Owner Association (HOA) restrictions, which the Brightly’s did have. All explained the legal situation in Arizona and took photos for future reference.
It was determined that the home had a south-facing main roof area with asphalt shingles at a four to twelve tilt (about 24 degrees), and with no shadows on the roof from other homes or trees.  The south side was the back of the house and the electrical service was on the east side of the house with 200-amp service and available space in the circuit breaker panel for a 2-pole breaker. Because of their HOA, the Brightly family also had the requirement of applying for permission from the Architectural Review Committee to install the system.
They were now faced with evaluating three differing bids, some with size options. All suppliers offered different brands of PV modules, different inverters, and different mounting kits. This was all very confusing. The family asked for some customer references and even looked at one system that was nearby. They checked the contractor names on the Arizona Registrar of Contractors website ( and all were in good standing with residential electric (R11 or CR11) electric licenses.
The Brightly’s used several methods to compare and rank the possible suppliers:
Calculated the cost per installed watt for each quotation. This resulted in figures running from $2.30to $4.00 per peak watt (the maximum rated output) prior to any rebates.  Small systems had the higher cost per watt.

For comparison the Brightly's calculated the estimated annual kilowatt-hours per PV array installed. This resulted in figures running from 1,680-1,825 kWh.  The supplier with the higher figure could not give a good reference for the value, while the others stated that their calculated estimate closely matched the measured performance over a few years by a local utility in Phoenix.

They then calculated the cost per estimated annual kilowatt-hour for each quotation. This resulted in figures running from $1.60 to $2.25 per annual kilowatt-hour. 
They eliminated the supplier who could not justify the high estimated annual output calculation. The decision between the other two suppliers was more subjective and they decided on the supplier who best answered their questions.
They asked the successful supplier back to settle on a specific system size and layout on their home. They asked the supplier if he could help with the HOA application and the supplier agreed and marked up a photo of the home to show the proposed changes.
With the signing of a contract and an initial payment, the supplier prepared the basic utility reservation for an incentive payment. Both parties signed the reservation and it was sent in to the utility. The utility generally acts on the reservation and sends the homeowner an Interconnection Application with their requirements identified.
The Brightly family contacted their HOA and picked up an HOA application. After asking the supplier for a few details, the application was filled out and submitted along with the requested fee. The application was approved and the Brightly’s were on their way to a clean and renewable source of energy.
Although your experience may not be exactly like the Brightly’s, there are certain steps that your contractor can do to facilitate the process. In addition to ordering the materials and scheduling the installation, the supplier usually has two related tasks:

  1. Prepare a set of drawings detailing the system installation for submittal to the local city for a building permit. The drawings and the application, along with the fee were submitted. The city building inspector required specifications of the PV modules, inverter, safety disconnect and mounting details. This was simple compared to some jurisdictions and earlier practices when photovoltaic systems were new technology.  Depending on system size and the experience of the building inspector with PV systems, the permit process can range from simple to complex. As an example, the Solar ABCs-developed standardized permit application intended to be adopted by cities and counties is linked here for reference <>.  Most counties and larger Arizona cities have blank permit applications available online, but the forms do not detail all of the submittal requirements. Experienced PV installers have expertise in this area. The permits require identification of the licensed installer and are usually applied for by the system supplier. The building permit generally requires about a 2% fee; it is recommended to call first and get an estimate.  Fees are based on the contract price. The permit is generally required to be posted on the building where inspectors can easily find it.
  2. The supplier submits the required drawings and information on the utility’s Interconnection Application form for approval of the PV system. Documents are generally signed by both the homeowner and the supplier. Requirements vary by utility, so refer to the website of the utility serving the home.

After both the permit and the Interconnection Application are approved, the system can be installed.
Installation generally requires 2-3 days depending on crew and system size.
After the system is installed, both the HOA and Building Inspector are notified of completion and the system is inspected. The Building Inspector will inspect the installation (but cannot operate the system due to the utility policy detailed in the Interconnect Agreement) and if all is good, will issue a ‘Green Tag’ and close the permit. The installer must correct any problems that arise.
The utility is then notified of the passed building permit inspection (they may want a faxed copy of the inspection tag) and will schedule the utility inspection. If all is in order (the utility is particularly interested in the grounding, cable sizes, required labels of parts, usually detailed in their Interconnect Agreement), the utility will turn on the inverter, observe proper operation, make a disconnection test, and then leave the system operating. Again, if there are any problems the installer is responsible for correcting them.
After the inspection, the utility generally requires an Installation Certification Form (name varies) along with copies of invoices and a statement of payments showing that the homeowners have paid for their portion of the system. Some utilities offer assignment of incentives to the installer. The utility generally mails the incentive payment check within a few weeks.
This might seem like the end of the path, but it is not. With the system now operating, the supplier should schedule a training visit with the homeowner and train the homeowner on system operation.
The homeowner is due a copy of all user manuals (a system manual is often prepared that contains copies of all documentation). Arizona law (see requires that the homeowner be furnished a written statement of certification and a statement of performance. This must include what general performance the purchaser can expect from the system under typical conditions in addition to a statement of warranty.
There is really no end of the path, but just like the Brightly’s, yours can begin here. Your system should operate for over 25 years with minimal attention and continue to provide benefits that the whole family can share.
A quote from a Scientific American article sums it up:
“But the upside is that homeowners with photovoltaic panels on their rooftops can rest assured that as long as the sun shines, they will have power to spare without generating emissions of carbon dioxide and other noxious pollutants.”


  • Welcome to the Arizona Solar Center

     This is your source for solar and renewable energy information in Arizona. Explore various technologies, including photovoltaics, solar water heating, solar architecture, solar cooking and wind power. Keep up to date on the latest industry news. Follow relevant lectures, expositions and tours. Whether you are a homeowner looking to become more energy efficient, a student learning the science behind the technologies or an industry professional, you will find valuable information here.
  • About The Arizona Solar Center

    About The Arizona Solar Center Arizona Solar Center Mission- The mission of the Arizona Solar Center is to enhance the utilization of renewable energy, educate Arizona's residents on solar technology developments, support commerce and industry in the development of solar and other sustainable technologies and coordinate these efforts throughout the state of Arizona. About the Arizona Solar Center- The Arizona Solar Center (AzSC) provides a broad-based understanding of solar energy, especially as it pertains to Arizona. Registered Read More
  • 1