Dear Mark,
I think that SAM is modeling the commercial system as you want it to.
When you model a system in SAM using either the Commercial or Residential financial model, SAM calculates the project revenue based on the quantity of electricity delivered to the grid after meeting the building or facility load defined on the Electric Load page. In the cash flow table, SAM displays the total quantity of electricity generated by the system as "Energy (kWh)" in the first row, but the value of that energy ("Energy Value" in the second row) is based on the portion of that energy that was delivered to the grid. SAM calculates the income tax amount by applying the state and federal income tax rates to the energy value.
On the Utility Rate page, "net metering" means that the buy rate is equal to the sell rate, which I think is different than your use of the terms "net metering" and "gross metering." In the U.S., "net metering" refers to a set of local laws that determine how an electric utility sets prices for electricity that it purchases from its power-generating consumers.
To model your project, on the Utility Rates page, clear the "Enable net metering" check box, and use Flat Buy Rate for the power purchase price, and Flat Sell Rate for the FiT (feed-in tariff) rate. Unless you want to model time-of-use or tiered rates, make sure all of the other check boxes are clear. Then, on the Electric Load page, specify the in-house electricity consumption that the system will meet before selling power to the grid. That should model the revenue portion of the project as you describe.
Specifying the load data in SAM can be a little tricky. I've tried to explain it in the
Electric Load topic in Help
(you can also access that topic directly from the Electric Load page in SAM), but let me know if you have questions about how to do that.
Also, you may be interested in
this newsletter announcement
from AUSTELA describing work IT Power (Australia) did with us to develop sample files and a handbook for modeling Australian CSP projects in SAM.
Best regards,
Paul.
