Dear Amirsaman,
Thank you for the message.
When you create a project in SAM, you choose a performance model and a financial model. For example, to model a residential project like a roof-top system on a house, you could choose the Detailed Photovoltaic model and the Residential Financial model. To model a ground-mounted PV system on a farm or a roof-top system on a factory, you could choose the Detailed Photovoltaic model and the Commercial Financial model.
The residential and commercial projects use the same performance model, but different financial models. In general, PV systems for residential projects tend to be smaller than commercial ones, and those tend to be smaller than utility-scale (or industrial) projects. However, SAM does not prevent you from modeling a large PV system with the Residential financial model, or a small system with the Commercial model or one of the PPA financial models for utility-scale projects. It is up to you to design a system that is appropriate for your analysis.
The different financial models allow for different debt and other financial features. For example, the residential model has options for a standard or mortgage loan. The commercial model has options for depreciation that is not available in the residential model. Both the residential and commercial models assume that the PV system is used to reduce the building or facility electricity bill. The PPA models, on the other hand, are for power generation projects that earn revenue by selling electricity at a price determined by a power purchase agreement (PPA). Those models have more sophisticated financial features appropriate for a power generation project like reserve accounts, internal rate of return requirements, sculpted debt, etc.
Best regards,
Paul.
