Metrics Table |  |  |  |

| This topic describes SAM 3.0 and has not been revised for SAM 2009 Beta. You may find useful information, especially if you are new to SAM, but some of the information may be inconsistent with the new version.

The variables that appear in the Metrics table depend on the system being modeled. For example, the Metrics table below on the left is for a residential system and displays fewer variables than the table on the right, which is for a utility system with IPP financing.

To export data from the table for use in a document, either right-click the Metrics table to copy its contents and paste it into the document or open the results spreadsheet and click the Metrics Table tab.

The Base column in the Metrics table displays results calculated from values of input variables as they appear on the input pages. The Slider column displays results calculated from the values of input variables shown on sliders: Moving a slider's pointer changes values in the Slider column (and graph), but not in the Base column. See Sliders for more information about setting up and using sliders.

This section describes the variables shown in the Metrics table.

Metrics Table Variables

The variables that appear in the Metrics table and on the Metrics Table tab in the Results spreadsheet depend on the type of financing defined on the Financials page. The variables followed by an asterisk (*) in the table below are input variables from the Financials page that are included in the Metrics table for reference.

Table 23. Variables that appear in the Metrics table for different financing types.

Type of Financing | Variables in Metrics Table
Residential Cash Residential Mortgage Residential Loan | LCOE Net Present Value (NPV) Simple Payback kWh / kW - Year 1 Capacity Factor Annual Output - Year 1
Commercial Cash Commercial Loan | LCOE Tax Adjusted Utility Rate Net Present Value Simple Payback kWh / kW - Year Capacity Factor Annual Output - Year 1
Utility IPP Commercial Third Party System Ownership | LCOE Actual IRR Actual Min DSCR First Year PPA PPA Escalation Rate* Debt Fraction* Min Cash Flow kWh / kW - Year Capacity Factor Annual Output - Year 1

LCOE

The levelized cost of energy is defined as the present value of the total cost of installing and operating a power project over its economic life expressed in dollars per total kWh of energy produced over the project life.

For projects financed by cash, mortgage, or loan, the levelized cost of energy LCOE is calculated using the annual project cost, where C n is the cost in Year n, and C n=0 is the cost in year 0, equivalent to the capital cost. Q n is the electric energy produced by the system in year n. N is the project life time and d is the discount rate, both of which can be found on the Financials page:

For utility projects with independent power producer financing or commercial projects with third party ownership financing, the LCOE is calculated as above, except that the annual required revenue R Required,n replaces the annual cost:

For a detailed description of LCOE, see Levelized Cost of Energy (LCOE).

Note. The LCOE for the systems in the sample files includes the effects of incentives. To see what the LCOE would be with no incentives, set the sliders for all incentives to zero, and read the LCOE value in the Slider column of the Metrics table. See Sliders for more information.

Net Present Value (NPV)

The net present value is the present value of the stream of after tax cash flows discounted to year one using the discount rate on the Financials page plus the after tax cash flow in year zero. The project cash flows are displayed on the results spreadsheets.

Simple Payback

The simple payback is the time in years starting in year one of the project that it takes for the cumulative cash flow to switch from negative to positive.

The payback cash flows for each year n are shown on the Cashflow tab of the results spreadsheets, and are calculated as follows:

The cumulative cash flow for each year is:

kWh / kW - Year 1

The kilowatt-hour per kilowatt-year metric is the annual electric output in year one E OutputYear1 divided by the system capacity P SystemCapacity. For photovoltaic systems, the system capacity is the Array Power on the Array page. For concentrating solar power systems, the system capacity is the Rated Turbine Net Capacity on the Power Block page.

Capacity Factor

The Capacity Factor CF is the first year annual electric output E OutputYear1 divided by the system capacity P SystemCapacity divided by 8,760 hours per year. The system capacity for photovoltaic systems is Array Power on the Array page, and for concentrating solar power systems is the Rated Turbine Net Capacity on the Power Block page.

Annual Output - Year 1

The annual output in year one is the number of kilowatt-hours or megawatt-hours produced by the system in its first year of operation. Note that output in subsequent years may be lower than the first year depending on the value of the degradation rate on the Array page for photovoltaic systems and on the Power Block page for concentrating solar power systems.

Note that the system's annual output is displayed on the Output graph on the Results Summary page, and on the cash flow tab in the results spreadsheet.

Tax Adjusted Utility Rate

The tax adjusted utility rate is the Utility Rate on the Utility Rates page less state and federal taxes:

The effective tax rate is a single number that includes both the federal income tax rate and state income tax rate. Solar Advisor uses the effective tax rate for several calculations requiring a total income tax value.

The effective tax rate calculation is:

The federal tax rate and state tax rate are input variables on the Financials page.

Actual IRR, Actual Min DSCR, and First Year PPA

For utility projects with IPP financing and commercial projects with third party ownership financing, Solar Advisor calculates the internal rate of return (Actual IRR), minimum debt service coverage ratio (Actual Min DSCR), and first year electricity sales price (First Year PPA) to meet a set constraints, which are inputs on the Financials page.

You can find annual values of the required revenue, after tax cash flow, interest and principal payment, and operating cost variables shown in the equations below on the Cashflow tab of the the results spreadsheet.

The actual internal rate of return is the discount rate, IRR, that corresponds to a project net present value, NPV, of zero:

The debt service coverage ratio in each analysis year (DSCR n) is the ratio of operating income to expenses in that year:

In Solar Advisor, the project's debt service coverage ratio (reported in results as the actual minimum DSCR) is the lowest value of the DSCR that occurs in the life of the project:

Solar Advisor calculates the first year sales price, FirstYearPPA, by using an iterative search algorithm to find the first year sales price that, when inflated using the user-defined escalation rate, meets the constraints defined on the Financials page. For projects with "IPP and Utility" financing, the constraints are the minimum required IRR and the minimum required DSCR constraints, and a positive cash flow requirement:

Find FirstYearPPA such that

Actual IRR ≥ Minimum Required IRR, and

Actual Min DSCR ≥ Minimum Required DSCR, and
Cash Flow in Year n > 0 (when the cash flow requirement is positive)

For projects with "Third Party System Ownership" financing, the constraint is the minimum required IRR:

Find FirstYearPPA such that

Actual IRR ≥ Minimum Required IRR, and

Note that the minimum required IRR and DSCR are user input variables on the Financials page. The positive cash flow requirement is set by a check box on the Financials page.

Min Cash Flow

The minimum cash flow is the lowest positive value in the after tax net equity cash flow, which is displayed in the both Cashflow standard graph on the Results Summary page and on the Cashflow tab of the results spreadsheet.