Bring in the Solar Batteries

By Russell Lowes, Rincon Group Energy Subcommittee Chair, April 2, 2017

Have you ever wanted to get off the electricity grid? You might have a number of reasons to do so. What about saving money? The economic breakeven may be here sooner than you think. There’s an interesting and eye-opening thing you can do with energy usage and cost numbers (step 4, below) to make your own cost estimates.

Let’s say that you have decided there are four things you want to do at your house. One, you want to reduce your energy use. Two, you want to buy solar. Three, you want to buy a battery system to back up your solar when the sun is not shining. Four, you want to go off the electricity grid.

This is how the process of battery-backed solar might work in the near future. However, you can get started with step 1 & 2 right now, and later with steps 3 & 4.

1) Reducing Energy Consumption

  • Let’s say you use 575 kilowatt hours (kWhe) of energy per month, a typical usage rate in southern Arizona;
  • 200 kWhe is a typical reduction per month by using energy efficiency techniques like insulating shades for your windows, weatherization, insulation for your attic, or getting a an evaporative cooler “piggyback system” added to your air conditioning system.

This translates into:

  • Your usage has been 575 kWhe X 11¢/kWhe, a typical energy cost in So. AZ, which equals $63.25 plus basic service charge, and other charges per month, going down to:
  • Your new usage, with a 200 kWhe reduction, would be 375 X 11¢/kWhe, or $41.25/month + other base utility charges.
  • If you were to leave it at that and not do the next steps, you savings would be $22.00/month, $264/year, $5280/20 years.

2) Adding Solar to Your House

Now that you have reduced your energy consumption, when you add solar, you won’t have to buy as many panels. Instead of paying for maybe 5.6 kilowatts of capacity (the average used by the National Renewable Energy Lab, at, you now would buy around 3.9 kWe.

Your new solar panel array would deliver energy at about 7.0¢ per kilowatt-hour to your home, plus financing, so maybe 8.5¢.

Solar Prices Continuing to Fall

Solar Prices Continuing to Fall “NREL Report Shows U.S. Solar Photovoltaic Costs Continuing to Fall in 2016” September 28, 2016 *
Solar Prices Continuing to Fall “NREL Report Shows U.S. Solar Photovoltaic Costs Continuing to Fall in 2016” September 28, 2016 *

3) Adding Battery Backup to Your Rooftop Solar

Batteries are the big unknown in this process. Costs are falling quickly, and there is a goal by the industry to bring them down to 14¢/kWhe, when combined with solar. This is a bit more costly, when compared to the roughly 11¢ average cost of electricity by the utilities of southern Arizona. However, you only have to get a portion of your energy from batteries, and with lower solar costs here in the Southwest, the deal gets sweeter. For example, you can get 35% of your energy needs met with energy efficiency, from step 1 above, and 45% from solar, from step 2, and 20% from battery energy, from step 3, well that leads us to that point I opened with. . .

4) Going Off-Grid . . . “There’s an interesting and eye-opening thing you can do with energy usage and cost numbers.”

First, you have to boost the number of solar panels a bit to power the batteries, so your cost of solar would go up from 8.5¢ to roughly 10¢/solar kWhe, fully financed. Let’s project that future battery costs are 20¢/kWhe, fully financed.

Take a look at the following table and if you copy these values and formulas onto a spreadsheet (or ask me for a copy at, you can change the percentages in column D, and as long as the total equals 100% at the bottom of that column, all the figures will automatically and accurately update! Likewise, if you change any of the projected costs/kWhe in column E, the spreadsheet will auto-self-adjust. But, you math wizards out there already knew that!

This has been about the process of going off the grid, but there are reasons to stay on the grid. The main one is so you can share your electrons with others so they don’t have to use coal, gas or nuclear energy from the grid. However, if the utilities resist the solar revolution, we may not have much choice. If the utilities keep fighting solar rooftop and keep putting onerous charges on our bills, the best choice for you and your family, and for you and your business, might be to go off-grid.


*A side note about the above NREL chart: One interesting thing about the residential-size solar (rooftop solar) versus centralized utility scale is that with rooftop there is much less non-power-generation cost. With centralized solar there are new transmission requirements, more distribution costs, land acquisition costs, switch yard and substation and a myriad of other costs that are not required, as much, as with rooftop solar. Right now, rooftop solar is cheaper when you consider these non-generation costs. I believe that rooftop solar will widen the gap of cost benefit over large utility-scale centralized solar in coming years.


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

Re-Think Nuclear

Presented as a one-page primer for the Sustainable Tucson Newsletter

By Russell Lowes, February 27, 2010

The real choice is not nuclear versus coal, but nukes & coal versus the reasonable alternatives. 

There is massive opposition to coal now, which comprises about 45% of U.S. electricity. You can see smoke from the stacks or read about its CO2 emissions.

Opposition to nuclear energy is also amassing. Nuclear also produces CO2 emissions, which are growing ever-greater. It emits invisible radioactivity, uses even more water, and is much pricier. Here are some of the problems with nuclear energy.

Safety Issues Persist: The world has 436 reactors. In order to have a significant contribution to world energy, 1000 reactors are projected. Even if future reactor accidents improve by a factor of 10, the chance of a reactor meltdown would be roughly one more Chernobyl-like “sacrifice zone” by 2050.

Terrorist Issues: Shortly after the 9/11 New York jetliner crashes, the NRC corrected itself saying that airliners could destroy U.S. reactors. There is an even greater threat at the adjacent spent fuel cooling pools, housed in non-hardened buildings which, if breached, could create a meltdown.

Poor Economics/Subsidies Required: Nuclear electricity would run about 25 cents per kilowatt-hour to your meter. Current Tucson electricity is about 11 cents. New coal would be about 16 cents, wind at 12, solar photovoltaic at 24, gas at 13. The best option, however, is reducing energy with better lighting, architecture, insulation, A/C efficiency, etc.  Energy efficiency averages about 3 cents. Numerous nuclear industry officials have said they will build no new reactors without taxpayer loan guarantees.

Two Ways to Worsen Global Warming: Investing 1 dollar in nuclear rather than energy efficiency, you forgo saving 8 times the electricity. In other words, you can invest 1 dollar in nuclear and get 4 kilowatt-hours – or you can invest in energy savings and get 33 KWH. Investing in nuclear energy will dominate energy dollars, setting back the real options.

Second, nukes produce about 110 grams of CO2 per kilowatt-hour. This is 11 times the CO2 of wind, double that of solar, and many times that of energy savings/efficiency. It gets worse if you include 1 million years of waste storage.

Water Consumption Is Highest: Water lost to the environment at Palo Verde is about 0.8 gallons per kilowatt-hour. Coal consumes 0.5 gallons. With solar PV, wind and energy savings, water use is negligible.

National Security Is Diminished: We import 80-92% of our U.S. nuclear fuel. Energy independence is set back with nuclear.

Waste Legacy: The U.S. courts have ruled that nuclear waste much be safeguarded for 1 million years, 25,000 times the 40-year operating life of a reactor.

Russell Lowes is Research Director for He was the primary author of a book on the Palo Verde Nuclear Power Plant, the largest U.S. nuclear plant upwind of Tucson about 125 miles. This book was used in a campaign to successfully stop two reactors at this now three-reactor complex. You can contact Russell Lowes for presentations or for questions at  Documentation to this article can be found at