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Answers to Key

1. Rebates and Credits
2. The Costs
3. Solar Production
4. Environmental Impact
5. Financing
6. The Solar Technology
7. Design Considerations
8. Residential Solar
9. ABC Solar News
10. The ABC Solar Team


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2. The Costs

For example, a 25,000 square foot roof at 60% coverage will accommodate 1,000 solar panels at 180 watts each which equals 180KW DC. Each panel is about 15 square feet. This system will generate 27,000 kWh a month on average.

Commercial Solar Example

System Size 180,000
No of panels 1,000
Size of Panels in DC Watts 180
Sun Hours (4.2 matches SCE calculator) 4.2
Electric Rate $0.25
Electric Rate Growth 5.45%
Total Installed Cost Estimate $1,538,117
Rebate Estimate $296,671
Fed Tax Credit (30%) $372,434
Total Before Depreciation $869,012
1st year depreciation bonus $434,506
5 year depreciation $434,506
Total After Depreciation $0.00

Estimate Tax Rate 40%
Annual Solar kWh production 275,940
Annual Solar Production Value $68,985
20 Year Solar Value $2,392,609
40 Year Solar Value $9,307,787
Internal Rate of Return (IRR) 17.17%
20 Year Return on Investment (ROI) 175%
40 Year Return on Investment (ROI) 971%

We will make a proposal specific to your company's situation.

The Solar rebate is calculated with the following information:

  • calculator says this system will produce 270,817 kWh a year
  • Step 4 of the California Rebate Program is $0.22 per kWh produced during first 5 years

    Please note that all commercial rebates require a 1% deposit paid to the Rebate Administrators. This means the 1000 panel system will require a rebate deposit of $3,472.00.

    The following is from the required SCE CSI rebate application process website at

    Please remember that ABC Solar Inc will handle turnkey all the details of your solar installation.

    Proposed Reference
    Site Specifications:
    ZIP Code 92110 92867
    City San Diego Orange
    Utility SDG&E
    Customer Type Commercial
    PV System Specifications:
    PV Module Mitsubishi Electric Corporation:PV-MF180UD4
    Number of Modules 1000 1000
    DC Rating (kW STC) 180.0000 180.0000
    DC Rating (kW PTC) 159.0000 159.0000
    Inverter SMA America:SB7000US (208V)
    Number of Inverters 30 30
    Inverter Efficiency (%) 95.50 % 95.50 %
    Shading Minimal Shading Minimal Shading
    Array Tilt (degrees) 15
    Array Azimuth (degrees) 180
    Optimal Tilt (proposed azimuth) 17
    Optimal Tilt (facing South) 17 17
    Annual kWh 267,562 (a)
    at optimal tilt 269,634 (b)
    facing south at optimal tilt 269,634 (c) 270,459 (d)
    Summer Months May-October May-October
    Summer kWh 150,339 (e)
    at optimal tilt 150,411 (f)
    facing south at optimal tilt 150,411 (g) 156,162 (h)
    CEC-AC Rating 151.845 kW
    Systems greater than or equal to 50 kW (CEC-AC rating) are ineligible for EPBB incentives.
    Design Correction1 99.952%
    Geographic Correction2 99.695%
    Design Factor3 99.647%
    Incentive Rate $1.89/Watt Eligible Incentive4 $1.90/Watt Reference Incentive
    Incentive5 $287,487
    Report Generated on 2/24/2008 1:45:17 PM
    The CSI-EPBB calculator is a tool available to the public and participants of the CSI program, whose sole purpose is to determine the EPBB Design Factor and calculate an appropriate incentive level based on a reasonable expectation of performance for an individual system. The results of the calculator should not be interpreted as a guarantee of system performance. Actual performance of an installed PV system is based on numerous factors, and may differ with the results summarized in the CSI-EPBB calculator. For this reason, contractors, participating customers, and other interested parties should only utilize the calculator to determine an appropriate incentive when applying to the CSI incentive program. Additional uses for the calculator other than its intended purpose as stated above are not endorsed or encouraged.
    Notes: Design Correction: This is the ratio of the summer output of the proposed system (e) and the summer output of the summer optimal system at the proposed location (f). Geographic Correction: This is the ratio of the annual output of the summer optimal south facing system at the proposed location (c) and the annual output of the summer optimal south facing system at the reference location (d). Design Factor: This is the product of the Design Correction and Geographic Correction. Eligible Incentive Rate: This is the product of the Design Factor and the current CSI EPBB reference incentive rate (which depends on the selected utility and customer type). Incentive: This is the total incentive for the proposed system. It is the product of the CEC-AC Rating and the Eligible Incentive Rate. As of 8/10/07, the CSI-EPBB calculator performs rounding as follows:

  • Estimated kWh production is rounded to the kWh
  • CEC-AC rating is rounded to the watt
  • Design factor is rounded to 5 significant digits
  • Incentive is rounded to the dollar

    180w Solar Panels - 24v 1000 $792,000
    SB7000US 30 $105,600
    Mounting Hardware 1 $74,415
    Product Sub Total $972,015
    Tax $80,191
    Shipping $20,000
    Product Grand Total $1,072,206
    Installation Estimate $158,400
    Total $1,230,606
    Solar Rebate estimate (step 4) Paid over five years $443,071
    FED tax credit $236,261
    5 year depreciation estimate $192,946
    Grand Total $358,329

    The LADWP rebate calculator says this system will make 263,607 kWh a year. The LADWP rebate math is $0.11 per kWh for 20 year production estimate. The math is:

    Estimated Production
    *20 years
    *0.955 inverter efficiency
    *0.80 de-rate factor
    *$0.11 rebate per kWh production


    263,607 * 20 * .955 * .8 * .11 = $443,071

    This rebate is paid in full after successful construction and rebate appliction completion.

    The LADWP calculator says this for production

    Don't touch that dial! It's time for:

    Station Identification
    Cell ID: 0174360
    State: California  
    Latitude: 34.1 ° N
    Longitude:     118.6 ° W
    PV System Specifications
    DC Rating: 180.0 kW
    DC to AC Derate Factor: 0.770
    AC Rating: 138.6 kW
    Array Type: Fixed Tilt  
    Array Tilt: 17.0 °
    Array Azimuth: 180.0 °
    Energy Specifications
    Cost of Electricity:     11.9 ¢/kWh

  • Results


    (kWh/m 2 /day)


    4.04      16185  1932.81 
    4.69      17139  2046.74 
    5.68      22877  2731.97 
    6.40      24540  2930.57 
    7.02      27761  3315.22 
    7.15      26912  3213.83 
    7.06      27164  3243.93 
    6.95      26515  3166.42 
    6.15      22757  2717.64 
    10  5.04      19659  2347.68 
    11  4.42      17054  2036.59 
    12  3.76      15045  1796.67 
    Year  5.70      263607  31479.95


    Solar Products We Carry

    Solar Panels

    Sharp Solar
    Evergreen Solar
    Mitsubishi Solar
    BP Solar
    Kyocera Solar
    Ningbo Solar


    SMA America
    PV Powered

    Mounting Hardware

    Pro Solar


    Direct Power & Water

    This page is from ABCSOLAR Archive. Information on this page may be outdated, still very helpful and educational.