An Update on the War on Solar at the Arizona Corporation Commission

by Russell Lowes and Keith Bagwell

            Two utilities, Tucson Electric Power and its sister subsidiary UNS Electric, are applying for rate hikes with the Arizona Corporation Commission. Included in these rate cases is a troubling and unprecedented restructuring of how rates are applied. These proposed rate reshufflings are bad for the families and businesses in these monopoly areas. Additionally, these proposals are assaults on family and business-owned rooftop solar energy installations.

            TEP and UNS have engaged in a public relations campaign to promote the inaccurate idea that rooftop solar energy is costing non-solar customers more than if there was no additional rooftop solar installed.

            Tucson Electric Power has recently made a number of erroneous statements about rooftop solar costs. However, we will focus here on the most glaring blunder, in what has NOT been said. The utility company does not consider the “opportunity lost cost” for not going with rooftop solar. TEP again made this error of omission in a recent exchange with our County Board of Supervisors, who are opposing the proposed rate shuffle. That is, what happens if families and business owners, schools and local governments in the TEP service area do not install solar panels? TEP is installing centralized utility-owned solar energy plants, and this solar is costing non-solar customers much more than the customer-owned rooftop solar. See the table below, which further explains this.

Examples of Typical Un-Subsidized Energy Costs for New Power Capacity in Southern Arizona, in Cost Per Kilowatt-Hour

Energy Production & Efficiency Options

Initial Un-Subsidized Cost

Trans-mission & Distribution Component

Total Cost

Cost Covered by  Rooftop Solar Families & Business-Owners

Maximum Cost Borne by Ratepayers


Homeowner Rooftop Solar Financed with Homeowners Equity Line of Credit, 5%






Homeowner Rooftop Solar Financed with Lease






Medium-Size Business Rooftop Solar Financed with Commercial Loan, 6%






Utility-Owned Rooftop Solar, Financed with Blend of 50/50 Rate of Return and Corporate Bonds, 9% (per IRP)*






Utility-Owned Centralized Solar, Financed with Blend of 50/50 Rate of Return and Corporate Bonds, 9%






Utility Solar via Power Purchase Agreement (Subsidized Fixed Contract)






Utility-Owned Centralized Gas Plant Financed with Same Finance Mix






Energy Efficiency**







 * The vast majority of this cost will be borne by the ratepayer directly benefitting from this installation.

**Energy efficiency comes in many forms and at many different costs and benefits. The ratepayer-

   borne portion of this, on average is likely under 1¢ per kilowatt-hour saved.


            Recently TEP just secured more fossil fuel power capacity. This will cost much more for non-solar customers in total dollars, and in cents per kilowatt-hour.

            TEP claims that family-owned solar energy increases costs for its non-solar ratepayers. In this claim TEP is probably really talking about what the utility company losses will be. The company financial losses to customer energy efficiency and solar investments are real, if you do not count the gains to the company in terms of grid diversification, performance fees TEP earns on customer energy efficiency investments, etc. However, these gross costs (before these other offsetting benefits) are very minor, at this point of grid penetration, well under 5 percent.   

            What TEP and UNS Electric ignore, in this “solar costs non-solar customers argument,” is that all the other options of electricity generation expansion are more expensive than customer-installed rooftop solar. Centralized solar built by the utilities costs non-solar customers far more than rooftop solar. Fossil-fuel generation is even more expensive, as well as polluting and climate-changing. In addition, the 0.5¢/kilowatt-hour cost that is purported to be shifted to non-solar customers, is actually returned to customers numerous times, by diversification of the grid, reduction in peak gas-generated electricity, and by many other benefits that solar provides to all families and businesses.

            Consequently, it is in the best interest of our families and business-owners that customer-owned rooftop solar continues to be installed, under the current net-metering system. This is not best for the utilities only under the current business models that are now outdated. These models need to change. The Commission needs to require that TEP and UNS update their business models to mesh with the new technologies, the new ways in which people are living, and the improving costs of options customers did not have until recently. Additionally, the business models need to be changed to reflect the far lower impact the newer technologies have on the environment and on human health.

            When a rooftop-solar customer invests in solar, that family or business pays all of the construction cost, all of the interest and all of the maintenance costs. These costs add up to about 11¢ per kilowatt-hour if financed through a home equity loan, or a business loan. When a utility builds solar, it pays for these three categories and more (land acquisition, transmission lines, etc.), but then passes it on to the ratepayers. Similarly, when TEP acquires more natural & fracked gas capacity, it pays for these components of overall cost and passes them on to the ratepayers.

            TEP and UNS should not be allowed to ignore the fact that if solar rooftop is not invested in by families and businesses, the utilities will have to invest in other more expensive power-generation options and pass those costs on to their customers. To ignore this is deceitful and only works to further undermine the trust of ratepayers in the TEP and UNS Electric monopolies.

>>>      Action to take! For anyone wanting to comment before these cases close, you could address your comment as follows. Nobody knows when these two rate cases will close, but it will probably be open through July or August of 2016.

Re: Rate Cases E-04204A-15, E01933A-15-0322 and E-00000J-14-0023

Dear Commissioners Little, Burns, Stump, Forese and Tobin,


Methodology and References  

  1. a) This is calculated based on typical sale price of $3000/kilowatt of D/C electrical capacity, .8431 conversion rate to A/C electricity, a lifetime average degradation rate of 13.2% over the 30 year minimum life span, with a capacity factor (average output, compared to A/C rating) of 20.85% with 5% APR financing for a home equity line of credit (HELOC).
  2. b) Based on reviews of leases for solar homes in Tucson, Arizona, by one of the authors, Russell Lowes.
  3. c) Based on lower cost per kilowatt installed but higher loan rate, 6% APR.
  4. d) Based on $2800/kW D/C, 0.8431 conversion rate to A/C, a 13.2% average degradation rate for a 30 years, with a capacity factor of 20.85%, with 9% average financing, per Tucson Electric Power Integrated Resource Plan, which lists 8% as the average corporate bond rate, 10% as the average rate of return on equity and a typical 50/50% blend of the two financing options.
  5. e) Based on $2200/kW D/C, 0.86 conversion rate to A/C, a lower 9.5% average degradation rate for a 30 years, with a lower capacity factor of 18.3%, with X% average financing, based on the Tucson Electric Power Integrated Resource Plan, which lists X% as the average corporate bond rate, X% as the average rate of return on equity and a typical 50/50% blend of the two financing options.
  6. f) Based on what TEP is typically getting for Power Purchase Agreements and what it uses as the basis for its proposal to reimburse solar rooftop owners.
  7. g) Gas-produced power from Lazard’s Levelized Cost of Energy Analysis—Version 9.0, at:, p. 2 (click on “View the Study”). This is at the lower end of the two combined Gas Peaking and IGCC (more toward baseload) options. The average of these two is 16.6¢/kWhe. Additionally, see table below for similar approach to gas-generated electricity costs. This has to take into consideration more peaking energy costs for electricity that rooftop solar would displace. These costs can be as high as 21.8¢/kWh, according to Lazard, p. 2.
  8. h) , p. 2, energy efficiency is taken from the top of the range from Lazard’s (see g).

Cost for Conventional Combustion Turbine Gas Electrical Generating Plant

Using O&M & Fuel Costs from Table 8.4*, 2012 Dollars



kWe capacity scenario


cost per kWe**


Capitalization Rate (including principal, interest, taxes and fees)


Cost Per kWe Per Year



Cost Per kWhe for Capital


Hours Per Year


kWhe/Yr Generated



Cost Per kWhe for Capital








Subtotal O&M & Fuel


Total Cost Per kWhe


Non-Generation Utility Costs (incl. transmission, distribution, etc.)


Total Cost Per kWhe Delivered





Solar Under Siege | Alert: Three Arizona Electric Utilities Trying to Stop Solar Energy Rooftop Installations

UNS Electric, Inc., is the first of three utilities in Arizona to file a rate case to kill off the booming residential and business solar industry.  The utilities, UNS, Tucson Electric Power and Arizona Public Service, are undertaking a coordinated effort to increase rates, increase basic fees and wipe out family-owned solar energy rooftop installations. They hope to achieve this by implementing a new rate structure for consumers that includes three nasty components. These tactics are particularly detrimental to families and businesses in Arizona.  UNS is the first to propose it, but if the Arizona Corporation Commission (ACC) approves UNS’s proposal, the other two utilities are sure to follow.  The ACC is the regulatory commission for Arizona energy utilities.

First, UNS Electric wants to virtually eliminate a long-standing Arizona policy to put solar on parity with other energy options. This policy, called “net metering,” has been adopted by almost all states in the U.S.  Now UNS wants to reverse it in Arizona. Currently under this policy, your electric utility pays you the same rate for the excess solar electricity that you produce as you pay to buy energy from the grid when you need it. In other words, under the current system, if you have solar panels, the utility buys and sells energy from and to you at the same retail rate. UNS Electric wants to cut what they pay you in half. And then they would turnaround and sell the power that they buy from you to your neighbors for twice the price.
    Second, UNS  wants to increase the basic fee from $10 to $15 per month. This is bad in so many ways. It means a much bigger (50% bigger) portion of your bill would be beyond your control. When you reduce energy consumption, a move better for your pocketbook and for the planet, the fee would not go down. When you put solar on your house, which is better for your pocketbook and better for the planet, your fee would not go down. It is a disincentive to using your energy more wisely. And, because UNS gets the vast majority of their energy from coal and gas, it is a penalty to families that do the right thing by reducing their coal and gas-produced energy.
Finally, UNS wants to implement a demand charge for residential customers—something that no other major Arizona utility has imposed on residential users and is typically only used for commercial customers who are better able to control and track their usage. The “demand charge” would be a rate (cost per kilowatt-hour) calculation that would be assessed by UNS, and without notice to the customer, based on each customer’s highest energy peak usage over the worst 15 minute period in each month. So if your overall usage for a given month is lower than usual, if during that same month someone ran a number of appliances while the A/C was on over a 15 minute period, the cost per kilowatt-hour for the entire month would go up based on those brief 15 minutes. This would happen even if your peak was of no consequence to UNS.
    Not only have TEP and APS intervened in the UNS rate case on the side of UNS, all three companies have recently put forth the supposition that rooftop solar energy installed by one family is the cause of increased costs to other families. UNS and the other two utilities have been throwing out this concept, without referring to the other alternatives. Statements of costs of solar rooftop without comparing it to the other options are meaningless in the bigger picture. Energy costs for most other UNS options are much more expensive to these families without the participation of rooftop solar.
    If for example, UNS purchases solar energy at a large centralized solar facility, the cost per kilowatt-hour is currently about 6¢ for production, and going down each year, plus 6¢ for transmission and distribution, totaling 12¢/kilowatt-hour. This is after taking out about 2¢ from subsidies. New gas plants are about 13¢/ kilowatt-hour, with a likelihood of increasing fuel costs. This gas plant price is also is after subsidies are subtracted. New coal plants are about the same cost per kilowatt-hour.
    When UNS buys solar, or for that matter, gas or coal, the cost of construction is entirely passed on to the ratepayers, which includes families with and without solar. With utility solar, all ratepayers pay all the utility-solar-plant land acquisition costs, the environmental permit costs, the siting costs, equipment maintenance costs, increased transmission and distribution (T&D) costs, grounds cost, insurance, switch yard costs and more.  
    When a family or business decides to go rooftop solar, there are also system costs. However, instead of passing on these costs to other families, that solar family pays all the construction cost, all the interest costs, all of the other costs except a small portion of the normal transmission and distribution cost. The non-solar family would only pay a small added transmission and distribution cost. But this cost is very small compared to centralized plant T&D costs. The rooftop solar energy does not have to be transported on long-distance high voltage transmission lines. Rooftop solar largely uses existing lines. Under the UNS proposal, rooftop solar gets sold locally by UNS at a virtually 100% profit over a time span that is in an instant, not even the normal measurement of a year for return – that is price-gouging.
    In sum, the non-solar family pays much less for system expansion when the neighbor next door expands the system by 5 kilowatts, for example, compared to when the utility expands the system by that same 5 kilowatt of capacity.  Thus, the message that the Arizona utilities are crafting, that rooftop solar is costly, is false.  The much higher costs are with the other options of utility power plant construction and acquisition.  Moreover, solar energy offers substantial environmental benefits.  However, even without addressing these important advantages, solar rooftop costs less to all families, families with and without rooftop solar energy, than the alternative utility power plant expansion.
    I am hoping that many many ratepayers will submit comments to the ACC on this rate case. Please look over the action section below and at the URL in this section.


TAKE ACTION to keep the solar rooftop option thriving in Arizona! Send your comments to the ACC to the Sierra Club Chapter Director, Sandy Bahr (, as she has offered to get the 13 copies of our testimonies to the Arizona Corporation Commission, so that they will be a permanent part of the “docket,” or rate hearing case. Put at the top of your comments:
Regarding: UNS Electric Rate Case Docket # E-04204A-15-0142
You might address it with something like: “Dear Chairman Little and Members of the Arizona Corporation Commission:”
You can also find out more and comment at the Sierra Club’s