«CSI Incentive Calculator User Guide 1. Guide Overview This User Guide provides background on the California Solar Initiative (CSI) Incentive ...»
CSI Calculator v3 User Guide rev 6-3.doc
CSI Incentive Calculator
1. Guide Overview
This User Guide provides background on the California Solar Initiative (CSI) Incentive
Calculator, describes how the calculator determines the CSI incentives for a proposed
system and detailed step by step instructions on its use. The calculator is web-accessible
The CSI calculator is available to the public and participants in the CSI program. Its sole purpose is to calculate an appropriate incentive amount 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 influenced by numerous factors, and may differ from the results summarized in the CSI calculator. For this reason, contractors, participating customers, and other interested parties should utilize the calculator only to determine an appropriate incentive when applying to the CSI program. Additional uses for the calculator other than its intended purpose as stated above are not endorsed or encouraged.
The California Public Utilities Commission (CPUC) Decision 07-08-007, issued August 23, 2007, mandated modifications in the CSI calculator to include the performance of Building Integrated Photovoltaic Systems (BIPV). This User Guide provides information specific to the version of the CSI calculator that is BIPV compatible, which is identified by the header – California Solar Initiative Incentive Calculator – BIPV Compatible A detailed description of the modifications made to the CSI Calculator to accommodate BIPV performance is provided in Appendix A of this User Guide.
2. CSI Eligibility Eligible photovoltaic (PV) projects must be located within sites where the Host Customer is a Pacific Gas & Electric (PG&E), Southern California Edison (SCE) or San Diego Gas & Electric (SDG&E) retail electric customer.1 Systems between 1 kW and 5,000 kW are eligible to participate in CSI, however incentives are paid on the first 1,000 kW of installed capacity. Proposed systems that have a CEC-AC2 rating less than 50 kW3 are eligible for Expected Performance Based Buy down (EPBB) incentives. All systems are eligible for Performance Based Incentives (PBI).
Note that the California Center for Sustainable Energy (CCSE) is the Program Administrator for CSI in SDG&E’s service territory.
The CEC-AC rating is the product of the number of PV panels, the PTC rating per panel and the inverter efficiency.
The PV system capacity for eligible EPBB systems will be reduced to less than 30 kW in 2010.
May 7, 2008
All customer classes are eligible for CSI except for residential new construction systems which must apply to the New Solar Home Partnership (NSHP) program. NSHP details may be found at http://www.gosolarcalifornia.ca.gov/nshp/. The CSI calculator is currently not applicable to systems applying to the NSHP.
Program eligibility details can be found at the Go Solar California and CSI Program Administrators’ websites listed below
• Go Solar California http://www.gosolarcalifornia.ca.gov/
• PG&E http://www.pge.com/csi
• SCE http://www.sce.com/csi
• CCSE http://www.energycenter.org/ContentPage.asp?ContentID=377&SectionID=406& SectionTarget=370 Municipal electric utility customers are not eligible to receive incentives from the above designated program administrators.
3. CSI Incentive Calculator Overview The CSI calculator is an internet accessible tool (http://www.csi-epbb.com) used to determine the Design Factor and the resulting EPBB or PBI incentive for eligible CSI proposed systems.4 The calculator determines the CSI incentive for a single type of PV panel and inverter combination. The incentive for multiple units of the same type of PV panel and/or inverter can be accommodated by the calculator in a single calculation. Mixed systems that use different types of inverters, PV panels, tilts and/or azimuths require individual incentive calculations for each combination and the incentives summed. More details on mixed system CSI incentive calculation can be found in Section 6 of this guide.
When first opened, the calculator has an input page, where the user inputs the zip code location of the system, the customer’s electric utility, type of customer, incentive type, the type and number of PV modules, mounting method, the type and number of inverters, and the proposed system’s tilt and azimuth.
Once all required data is entered, the user initiates the calculator by pressing the “GO” button. The calculator then calls the National Renewable Energy Laboratory’s (NREL’s) PV Watts version 2 (PV Watts) performance calculator passing to it information on the proposed system and its location. The PV Watts model returns to the calculator the monthly electric energy production of the proposed PV system.
Note that CSI calculator PBI results are used by the Program Administrator to set-aside funds for future PBI payments. The CSI PBI results are not a guarantee of payment. PBI payments are based on the actual metered output of the proposed system.
The calculator then uses the PV Watts results to determine the resulting CSI incentive for the proposed system.
The overall process is illustrated below.
The user can press the “Recalculate” button, found at the bottom of the results screen, to return to the input page and make adjustments to their original inputs.
4. Required Calculator Inputs The CSI calculator is configured to calculate the incentive for a single PV panel type, inverter type with one tilt and azimuth. For example if a system utilizes two different inverter models, but the same type of PV panel, the calculator must be run twice. More details on mixed system EPBB incentive calculation can be found in Section 6 of this guide.
The inputs for the CSI EPBB Design Factor calculator are described below.
ZIP Code: This is the zip code of the location of the proposed PV system. Note that this zip code must be located within the specified utility’s service territory where the system is or will be located.
Utility: This is the utility in whose service territory the proposed PV system is or will be located. Note that the zip code inputted must be located within the specified utility’s service territory.
Customer Type: Select the customer classification associated with the Host Customer.
For definitions of the various customer types, refer to the latest California Solar Initiative Program Handbook.
Incentive Type: Select the incentive type, EPBB or PBI, being sought for the proposed system.5 Proposed systems that have a CEC-AC rating less than 50 kW are eligible for EPBB incentives. All systems are eligible for PBI. The incentive type changes how the calculator determines the incentive and changes the format of the results report.
PV Module: Select the module that will be used in the proposed PV system. The options in this pull-down are based on the CEC’s list of eligible photovoltaic modules, which can be found at http://www.consumerenergycenter.org/cgibin/eligible_pvmodules.cgi. If multiple module types are to be used, you must make multiple CSI calculator runs.
Number of Modules: This is the total number of PV modules of the selected type that will be connected to the inverter(s) that are selected below.
Mounting Method: This is the “average standoff” between the mounting surface and bottom of the PV module frame or mounting rack, which ever is closest to the mounting surface. The selections are – • 0" average standoff (flush mount or BIPV) – Where the PV mounting rack is in direct contact with the mounting surface or the PV modules lack outdoor air ventilation.
• 0" to 1" average standoff – The average standoff is 1” or less • 1" to 3" average standoff – The average standoff is 3” or less, but greater than 1” • 3" to 6" average standoff – The average standoff is 6” or less, but greater than 3” • 6" average standoff – The average standoff is greater than 6” “Average standoff” (SAVG) is the sum of the minimum and maximum standoff divided by two. Standoff is the distance perpendicular from the mounting surface to the bottom of the PV module frame. One minimum and maximum standoff distance must be established per array. See illustration below.
Inverter: This is the type of inverter that will be used with the proposed PV system. The options in this pull-down are based on the CEC’s list of eligible inverters found at http://www.consumerenergycenter.org/cgi-bin/eligible_inverters.cgi. If multiple inverter types are to be used, you must make multiple CSI calculator runs. Also, if the CEC-AC rating of the proposed system is greater than 125% of the inverter rating, an error is flagged which must be corrected (by reducing the number of panels, choosing a lower PTC rated panel, increasing the number of inverters or choosing a larger capacity inverter) before being allowed to proceed to the results page. See description of "CECAC Rating" in Section 5 of this guide for more discussion on oversized systems.
Number of Inverters: This is the total number of inverters of the selected type that will be installed for use with the PV modules selected above.
Minimal Shading: This criterion, if checked, indicates that no solar obstruction is closer than a distance twice the height it extends above the PV modules. If this criterion is met and Minimal Shading is checked, no derating due to shading is applied. Note that the reference optimal systems at the proposed and reference locations are always specified to meet the “Minimum Shading Criteria”.
Shading Derate Factors (%): If the proposed system does not meet the “Minimum Shading Criteria”, the user is required to input monthly non-shaded results from a shading study conducted at the proposed system site. If the Minimal Shading box is unchecked, a table form will appear where the user is to input each month’s non-shaded results from the shading study. See Section 7 for more details on obtaining and inputting the shading derate factors. The reference optimal system is specified to meet the “Minimum Shading Criteria” and thus has no derating of its monthly output due to shading.
Array Tilt (degrees): This is the proposed system tilt from horizontal. Flat (horizontal) systems have a 0º tilt.
Array Azimuth (degrees): This is the horizontal direction (“true” north-south) the proposed system is pointing; due South is 180º azimuth and due North is 0º azimuth. The optimal reference system for proposed flat (horizontal) systems is assumed to have a 180º azimuth. Magnetic direction measured by a compass can be converted to “true” direction by adding the appropriate magnetic declination for the specific location. Magnetic declination can be determined at the NOAA website (http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp).
After the inputs are set, the user can click the “GO” button and the calculations will be executed. If an input error is detected, the calculator will refresh the input page and note the error with a comment at the bottom and an asterisk next to the field containing the error. The error must be corrected before the calculator will proceed to the results output page.
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5. Description of the Outputs Once the calculator has completed its computations, it will display a results page containing inputs (Site Specifications and PV System Specifications) and outputs (Results) for the proposed and reference optimal system, as well as the Design Factor and calculated incentive. If the user wishes to apply to the CSI program, they must include a hardcopy of the CSI Calculator results screen in their application materials.
All production estimates are obtained from running NREL’s PV Watts v2 photovoltaic performance model using the proposed system parameters and weather data for the proposed and reference locations.
The outputs are described below. Note that there are differences in what results are reported for EPBB versus PBI incentives.
EPBB Incentives PV Module: Lists the specified PV module name and module DC rating per panel; STC, PTC and PTCadj. The PTCadj rating is not reported on the CEC website and is not equivalent to the PVUSA Test Conditions. It is calculated depending on the mounting method, NOCT and power temperature coefficient for that specific module. See Appendix A of this User Guide for a detailed description of the modified PTC calculation.
DC Rating (kW STC): This is the calculated total DC STC rated capacity of the PV modules and is calculated by multiplying the STC module rating by the number of panels. This capacity is used as an input to PV Watts to determine the performance of the system.
DC Rating (kW PTC): This is the calculated total DC PTC rated capacity of the PV modules and is calculated by multiplying the PTC module rating by the number of panels. This capacity is used to calculate the CEC-AC rating of the system.
Optimal Tilt (proposed azimuth): This is the system’s optimal tilt, maximizing summer output, at the proposed location. The optimal tilt also depends on the azimuth of the optimal reference system. The following illustrates how the reference system azimuth is set to equally treat south and west facing proposed systems.
Optimal Tilt (facing south): This is the tilt of summer optimal south facing systems at the proposed and reference locations.
Annual kWh: This is the estimated annual energy output of the proposed system. This value is reported for the sole purpose of transparency of the calculator and is not a guarantee of future system performance.
at optimal tilt: This is the estimated annual energy output of the summer optimized system at the proposed location. This value is reported for the sole purpose of transparency of the calculator.
facing south at optimal tilt: This is the estimated annual energy output of south facing summer optimized systems at the proposed and reference locations. These values are used to determine the Geographic Correction.