The SAM web site will be upgrading Monday, May 23 from 4:00-5:00pm (Denver/mountain time). 

After doing a major change to our infrastructure, we have found a minor issue that we have corrected but will need to reboot the web site for it to take affect.

To make it as convenient as possible, we have scheduled it for Monday, May 23rd at 4:00pm (mountain). The process takes 15-20 minutes, but the site will only be unavailable for a short time. However, your session information will be lost (eg if you're writing a post, what you have written could be lost). 

SAM's two Third Party Ownership financial models allow you to investigate a system installed on a residential or commercial building that is owned by a third party under either a power purchase agreement or lease agreement with the building owner.

For an overview of third party ownership financing, see the Solar Energy Industries Association Issues and Policies page on the topic.

Third Party Ownership - Host

The Third Party Ownership - Host model calculates the net present value of a renewable energy system installed on a residential or commercial property. The property owner, or host, makes an agreement with a third party who installs, operates, and owns the system. The system reduces the host's electricity bill, and the host makes payments to the owner.

In a power purchase agreement (PPA), the customer pays for the power generated by the system at a fixed rate called the PPA price. In a lease agreement, the host makes monthly lease payments on the system.

You can use the Third Party Ownership - Host model to:

  • Compare the benefit of a lease agreement to a PPA from the host's perspective.
  • Compare the Third Party Ownership - Host model to the Residential or Commercial model to compare third party ownership with direct ownership.
  • Investigate the value of different electricity rate structures and load profiles under a third party ownership agreement.

SAM's Third Party Ownership - Host model makes the following assumptions:

  • Project costs and benefits are from the host (residential or commercial property owner) perspective.
  • For a lease agreement, the host makes monthly lease payments with an optional annual escalation rate. Inflation does not apply to lease payments.
  • For a PPA, the host makes monthly payments for electricity generated by the system at the rate defined in the PPA with an optional annual escalation rate.
  • Inflation does not apply to monthly payments for either the lease agreement or PPA.

In the following video from a 2015 webinar, Nate Blair introduces and demonstrates SAM's Third Party Ownership - Host financial model.

Supporting materials:

Third Party Ownership - Host / Developer

The Third Party Ownership - Host / Developer model calculates financial metrics a renewable energy system installed on a residential or commercial property. The property owner, or host, makes an agreement with a third party, or developer, who installs, operates, and owns the system. The system reduces the host's electricity bill, and the host makes payments to the developer for the power generated by the system at a fixed rate negotiated through a power purchase agreement or PPA.

You can use the Third Party Ownership - Host model to:

  • Determine the PPA price that covers the developer's costs.
  • Investigate the value of different electricity rate structures and load profiles under a third party ownership agreement.

Sample Spreadsheet

This sample spreadsheets are intended to help you understand how SAM's Third Party Ownership - Host / Developer financial model calculates financial metrics such as the host and developer net present value (NPV) and the host indifference point.

The following Excel file was generated in SAM 2020.2.29 by clicking Send to Excel with equations from the Cash Flow tab on the Results page for the default PV - TPO Host/Developer case. It replicates SAM's calculations with Excel formulas using inputs from the SAM files. You can generate similar workbooks yourself from the Windows version SAM, or use these sample workbooks if you are using the Mac or Linux version of SAM, or not using SAM at all.

  • Third Party Host / Developer cash flow model (XLSX 264 KB)