Recent Updates

  • 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 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 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 Read More
  • Federal Residential Renewable Energy Tax Credit

    (Information provided by DSIRE - Last reviewed 02/19/2009) 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: 30% Maximum Incentive: Solar-electric systems placed in service before 2009: $2,000Solar-electric systems placed in service after 2008: no maximumSolar water heaters placed in service before 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 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 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
  2. Guest Blogs
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. 

Geoff Sutton
25 November 2017

In the desert south-west the intense sunshine and long summer days result in uncomfortable and even dangerously high temperatures for about four months.

Will add Guest Blog content here


Some things to pay attention to in Arizona

Reminder- Arizona tax credit information is available here: Arizona Tax Incentives



Proposed new rules covering connecting to the utility power grids in Arizona has been posted and a notice by the Hearing Division to hold oral proceedings to receive public comment on the Notice of Proposed Rulemaking on March 28. 2019. at 10:00 am. or as soon as practicable thereafter. in Room 722 at the Commissions offices in Tucson. Arizona and on March 29, 2019. at 10:00 a.m. or as soon as practicable thereafter, in Hearing Room No. I at the Commissions offices in Phoenix. Arizona.

A somewhat complex NOTICE can be downloaded at

UPDATE 1-24-19: ACC approved new draft interconnection rules At their Jan. 16 meeting, Commissioners preliminarily approved a set of rules that could help link renewables and batteries to the grid, making it easier for customers across the state to utilize.

There is a good description of these new rules and their significance at:

SRP is proposing three new Price Plans for Rooftop Solar

SRP is proposing three new price plans for residential customers who produce their own energy with rooftop solar and other technologies. Two of these options have no demand charge associated with them. See the SRP Proposal. Be sure to open the 'View graphics'. Specific rates are not shown. The Arizona Solar Center will have further details later.

APS announces 2018 ended with 16,479 applications and 14,818 installations: 

APS 2018 PV

Note: APS applications peak in August due to deadlines to freeze APS purchase rates for 10 years.


Attorney General Warns About Deceptive “Solar Initiative” Flyers

PHOENIX – Attorney General Mark Brnovich issued a warning today about deceptive flyers appearing on residences in the Phoenix area that promote a solar energy effort.

The flyers claim to be a “Public Notice” from the “Maricopa County Solar Initiative,” and claim that “Arizona and the Federal Government ITC (26 USC § 25D) are paying to have solar energy systems installed on qualified homes in this neighborhood.” The flyers tell consumers to call to schedule their “site audits.” Consumers who call are subjected to a solar sales pitch by a private company. In addition, the Maricopa County Solar Initiative’s website improperly uses a modified version of the county seal, but the “Solar Initiative” is linked to a private business and is not associated with the county. The “Solar Initiative” is also not registered to do business in Arizona.

Similar flyers previously appeared in Clark County, Nevada, this summer, and law enforcement officials there have warned that the “Clark County Solar Initiative” notices are deceptive.

Arizona Attorney General Mark Brnovich has aggressively prosecuted businesses masquerading as government agencies, including obtaining consent judgments against “Mandatory Poster Agency” and “Compliance Filings Service,” resulting in full restitution for Arizonans totaling hundreds of thousands of dollars.

A picture of the “Public Notice” is below:
A picture of the improperly modified county seal used by the “Solar Initiative” is below:

 If you believe you are a victim of consumer fraud, you can file a complaint online at the Arizona Attorney General’s website. You can also contact the Consumer Information and Complaints Unit in Phoenix at (602) 542-5763, in Tucson at (520) 628-6648, and outside of the metro areas at (800) 352-8431.


Also covered at:



War On Solar

Solar Roots Documentary - Movie Trailer

Mandalay to build 3,000 Arizona homes with solar and Sonnen batteries

(Reuters) - German battery maker Sonnen GmbH on Thursday said it would partner with home builder Mandalay Homes to outfit 3,000 new Arizona homes with batteries to store the excess energy generated by their rooftop solar installations.

A lithium battery unit of the startup "sonnen", formerly known as Sonnenbatterie, is seen in Berlin, Germany, October 14, 2016. REUTERS/Axel Schmidt

Mandalay plans to build the homes in Prescott, Arizona with the batteries, which can cost between $10,000 and $20,000. The cost would be part of the home’s sale price and wrapped into the mortgage.

The companies want utilities to pay the homeowners to use the stored power in the 3,000 batteries, which would create a virtual power plant with 8 megawatt hours of electricity, enough to power about 5,000 average homes for a day.

For now however, the project is moving forward without buy-in from utilities. Sonnen’s U.S. arm and Mandalay have been in talks with Pinnacle West Capital Corp’s Arizona Public Service and Salt River Project for a few months, they said.

The community would be the first of its kind in the United States, the companies said, and comes as utilities have been studying the potential benefits of integrating battery storage along distribution grids and decreasing reliance on centralized fossil fuel plants. Sonnen has several such communities in Germany, but the idea is still a novelty in the United States.

Batteries are viewed as especially key in large solar energy markets like Arizona that generate more power than they need during the sunniest times of the day.

Sonnen has about 1,000 home batteries deployed in the United States currently, and aims to get to at least 20,000 by 2020, in part through more deals with homebuilders.

Arizona Public Service would not comment on talks with Sonnen and Mandalay, but said batteries “can provide benefit to both our customers and the grid.”

Salt River Project spokeswoman Kathleen Mascarenas said “no agreements are in the works.”

Summary of Residential Rate Plans for APS Customers with an On-Site Distributed Generation System

Untitled Document

Summary of Residential Rate Plans for APS Customers with an On-Site Distributed Generation System

(Interconnect applications submitted after August 31, 2017)

This is not an official APS document, it is a summary of residential rate plans for APS customers with an on-site distributed generation system put together by the Arizona Solar Center from the August 19, 2017 rate schedules posted at See the actual rates by following the links at the above APS web page link. These are the charges for energy purchased from APS, see below for backfeed credits (exports of power to the grid).

APS Rate Plan - Customers with an on-site distributed generation system

Bundled rates





(Note 2)

Basic Daily Service





Energy Charges- per kWh

On-Peak Energy Charge-Summer










Off-Peak Energy Charge-Summer










Super Off-Peak Energy Charge

(November through April)





Demand Charges per kW (Note 1)

On-Peak Demand Charge:-Summer










Off-Peak Demand Charge:-Summer





All above 5 kW






All above 5 kW

Grid Access Charge per kW-dc of generation (Monthly fee)





APS Purchase Rates- per kWh

September 1, 2018 through

August 31, 2019

(Future rates to be determined)






Rate Periods for the above:

The On-Peak time period for residential rate schedules is 3 p.m. to 8 p.m. Monday through

Friday year round. Off-Peak time period is the rest of the day and holidays.

The Super Off-Peak period is 10 a.m. to 3 p.m. and applies to those plans with a rate shown above.

Holidays for Off-Peak:

  • New Year’s Day - January 1*
  • Martin Luther King Day - Third Monday in January
  • Presidents Day - Third Monday in February
  • Cesar Chavez Day - March 31*
  • Memorial Day - Last Monday in May
  • Independence Day - July 4*
  • Labor Day - First Monday in September
  • Veterans Day - November 11*
  • Thanksgiving - Fourth Thursday in November
  • Christmas Day - December 25*

*If these holidays fall on a Saturday, the preceding Friday will be Off-peak. If they fall on a

Sunday, the following Monday will be Off-Peak.

APS Residential bills will include the following adjustments:

  1. The Renewable Energy Adjustment Charge, Adjustment Schedule REAC-1. (
  2. The Power Supply Adjustment charge, Adjustment Schedule PSA-1.
  3. The Transmission Cost Adjustment charge, Adjustment Schedule TCA-1.
  4. The Environmental Improvement Surcharge, Adjustment Schedule EIS.
  5. The Demand Side Management Adjustment charge, Adjustment Schedule DSMAC-1.
  6. The Lost Fixed Cost Recovery Adjustment charge, Adjustment Schedule LFCR.
  7. The Tax Expense Adjustor Mechanism charge, Adjustment Schedule TEAM.
  8. Direct Access customers returning to Standard Offer service may be subject to a Returning Customer Direct Access Charge, Adjustment Schedule RCDAC-1.
  9. Any applicable taxes and governmental fees that are assessed on APS’s revenues, prices, sales volume, or generation volume.

And these Rate riders:

  • CPP -(RES) Critical Peak Pricing (Residential)
  • EPR-2 - Partial Requirements
  • EPR-6 - Partial Requirements – Net Metering (Residential Non-Solar)
  • RCP - Resource Comparison Proxy (This is for solar generation exports of power to the grid)
  • E-3 - Limited income discount
  • E-4 - Limited income medical discount
  • GPS-1, GPS-2, GPS-3 Â Green Power


  1. The kW used to determine the demand charge above will be the Customer's highest amount of demand (kW) averaged in a one-hour On-Peak period for the billing month.
  2. The SAVER CHOICE TECH rate schedule is available to residential Customers with the following:
    1. 1. Two or more qualifying primary on-site technologies purchased within 90 days of the customer enrolling in the rate; or
    2. 2. One qualifying primary on-site technology purchased within 90 days of the customer enrolling in the rate and two or more qualifying secondary on-site technologies.

Eclipse Effect on Mesa PV System

This is a plot of PV system output on August 21, 2017 in Mesa, Arizona.  Note the morning dip caused by the partial eclipse. The red line is the calculated average for the date, based on historical data.

Sonnen Signs a Deal to Put Storage in New Arizona Housing Developments


  • 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
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