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 https://www.nrel.gov/news/press/2016/37745.html), 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 russlowes@gmail.com), 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.

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*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.

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%

$0.115(a)

$0.005

$0.120

$0.115

$0.005

Homeowner Rooftop Solar Financed with Lease

$0.120(b)

$0.005

$0.125

$0.120

$0.005

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

$0.095(c)

$0.005

$0.100

$0.095

$0.005

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

$0.110(d)

$0.005

$0.115

$0.110

$0.115

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

$0.090(e)

$0.060

$0.150

$0.000

$0.150

Utility Solar via Power Purchase Agreement (Subsidized Fixed Contract)

$0.062(f)

$0.060

$0.122

$0.000

$0.122

Utility-Owned Centralized Gas Plant Financed with Same Finance Mix

$0.084(g)

$0.060

$0.144

$0.000

$0.144

Energy Efficiency**

$0.050(h)

$0.000

$0.050

$0.000

            **

           

 * 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,

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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: https://www.lazard.com/perspective/levelized-cost-of-energy-analysis-90/, 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

   

1

kWe capacity scenario

$973

cost per kWe**

12%

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

$117

Cost Per kWe Per Year

   

50%

Cost Per kWhe for Capital

8760

Hours Per Year

4380

kWhe/Yr Generated

   

$0.02666

Cost Per kWhe for Capital

$0.00263

  Operation

$0.00290

  Maintenance

$0.03706

  Fuel

$0.04259

Subtotal O&M & Fuel

$0.06925

Total Cost Per kWhe

$0.06000

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

$0.12925

Total Cost Per kWhe Delivered

   

*

www.eia.gov/electricity/annual/html/epa_08_04.html

**

http://www.eia.gov/forecasts/capitalcost/pdf/updated_capcost.pdf