Document Fervo_Project_Cape-4 use of SAM-EM

Author: softwareengineerprogrammer

docs/Fervo_Project_Cape-4.md

@@ -3,7 +3,9 @@
 This case study – example name: `Fervo_Project_Cape-4` – is a 500 MWe EGS Project modeled
 on Fervo Cape Station with its April 2025-announced
 [upsizing from 400 MW to 500 MW](https://fervoenergy.com/fervo-energy-announces-31-mw-power-purchase-agreement-with-shell-energy/),
-using a combination of publicly available data, extrapolations, and estimates.
+using a combination of publicly available data, extrapolations, and estimates. Financial results are calculated
+using
+the [SAM Single Owner PPA Economic Model](https://softwareengineerprogrammer.github.io/GEOPHIRES/SAM-Economic-Models.html#sam-single-owner-ppa).
 
 [Click here to go to the case study in the web interface](https://gtp.scientificwebservices.com/geophires/?geophires-example-id=Fervo_Project_Cape-4).
 
@@ -32,6 +34,7 @@ the [web interface](https://gtp.scientificwebservices.com/geophires/?geophires-e
 
 | Parameter                                                 | Input Value(s)                                                                                                         | Source                                                                                                                                                                                                                                                                                                                                                                                                  |
 |-----------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Economic Model                                            | SAM Single Owner PPA                                                                                                   | The SAM Single Owner PPA economic model is used to calculate financial results including LCOE, NPV, IRR, and pro-forma cash flow analysis. See [GEOPHIRES documentation of SAM Economic Models](https://softwareengineerprogrammer.github.io/GEOPHIRES/SAM-Economic-Models.html) for details on how System Advisor Model financial models are integrated into GEOPHIRES.                                |
 | Well diameter                                             | 9⅝ inches                                                                                                              | Next standard size up from 7", implied by announcement of "increasing casing diameter"                                                                                                                                                                                                                                                                                                                  |
 | Flow Rate per Production Well                             | 107 kg/s                                                                                                               | Maximum flow rate achieved at Cape Station per https://www.businesswire.com/news/home/20240910997008/en/Fervo-Energys-Record-Breaking-Production-Results-Showcase-Rapid-Scale-Up-of-Enhanced-Geothermal. The announced increased casing diameter implies higher flow rates.                                                                                                                             |
 | Number of doublets                                        | 59                                                                                                                     | Estimate based on extrapolation from previous case studies including [Project Red](https://gtp.scientificwebservices.com/geophires/?geophires-example-id=Fervo_Norbeck_Latimer_2023) and [Fervo_Project_Cape-3](https://gtp.scientificwebservices.com/geophires/?geophires-example-id=Fervo_Project_Cape-3)                                                                                             |