Hi Axel,
Thank you for your comments and suggestions.
We can change the formatting of numbers on the System Costs page to display more decimal places and avoid rounding numbers. Part of our thinking was to communicate that the model makes cost estimates rather than precise predictions, but I can see where that behavior might not be desirable.
As for the $/W units for the PV models, that convention is based on the history of U.S. Department of Energy using $/Wdc in photovoltaic cost studies, such as
these NREL benchmark costs
. However, other NREL cost reports such as the
Annual Technology Baseline
use $/kW. We'd be hesitant to change the units in SAM to $/kW for those people who are used to working with $/W
The land costs are designed for projects that purchase land. I agree that solar projects often lease land. You can account for that cost as an operating cost, but we will consider adding a specific category for land lease. You could use the "land purchase" category to represent the cost of securing the land lease, and then use the fixed annual O&M cost to represent the annual lease payment.
I'm not sure we will add more complexity to SAM's loan model. We try to strike a balance: It should model enough features to be useful to a wide range of users, but not so many as to be confusing.
One way to add complexity to the financial model for your own purposes is to set things up initially in SAM, and then use the "Send to Excel with Equations" option (Windows only) to export data from SAM to a fully functional Excel workbook that replicates SAM's financial model. You can then make changes in Excel to model the details of your project.
Best regards,
Paul.
