Hi Rafael,
To model a project with no debt, on the Financial Parameters page, choose the Debt percent option set the percentage to zero. Be sure to also set the debt closing costs to zero. Be sure to also consider the costs for construction financing interest and reserve accounts and adjust those as necessary for your project. (If the debt percent is zero, the debt service reserve account will come out to zero.)
I am not sure of the best way to model this $/kW payment. Aside from the capacity payment I mention above, you could also use the capacity based incentive (CBI) on the Incentives page.
I would recommend trying different approaches and carefully reviewing the cash flow on the Cash Flow tab of the Results page to see if the results are what you expect.
SAM does differentiate between the PV system capacity in kW, and the battery capacity in kW and kWh for installation and operating costs, but it does not provide options for distinguishing between PV and battery capacity or generation for revenue calculations so you will have to find a creative solution to model your situation.
Best regards,
Paul.