Combine Cases macro does not work for PV systems

[cpaulgilman]

The Combine Cases macro was not designed to work with lifetime simulations. As of SAM 2020.2.29 Detailed PV and Battery configurations run in lifetime mode to better model degradation effects, so the macro needs to be updated. Also need to verify that handling of DC degradation for PV performance models and AC degradation for non-PV is correct. (Older versions of SAM used AC degradation for all performance models.)

[cpaulgilman]

A workaround for now (see combine-cases-workaround-sam-2020-2-29r1.zip for an example):

1. Set up the SAM file as you usually would for the Combine Cases macro with a case for each sub-system and a Generic System case for the system's financial model. See the macro instructions for details.

2. Go to the first subsystem, and click Simulate.

3. On the Results page, click Data tables, and display the "System power generated (kW)" variable.

4. Click Save as CSV to save the data to a .csv file.

5. Use a spreadsheet program to open the .csv file.

6. In SAM, go to the case for next subsystem, run a simulation, and display the System power generated variable.

7. Click Copy to clipboard, and paste the data into the next column in the spreadsheet.

8. Repeat Steps 6 and 7 for each subsystem until you have a copy of each subsystem's output in columns in the spreadsheet. You may want to change the column headings to help you identify the subsystems.

9. Create a new column in the spreadsheet to calculate the total system output by adding the values of each subsystem's output. If your system includes a PV or battery subsystem, that subsystem will have results over the project lifetime, so 8760 * analysis_period. For this purpose, use only the data for Year 1, or the first 8760 values.

10. Select the column of 8760 values in the total column and copy it to your computer's clipboard (Ctrl-C, or Command-C on a Mac).

11. In SAM, go to the Generic System case's Power Plant page and click Import hourly or subhourly generation profile from file.

12. Click Edit array, and then Paste and verify that there are 8760 values in the table by scrolling down to the end of the table. If there are more than 8760 values, click Change time step and enter 60 to set the time step to 60 minutes, and repeat the paste process.

13. On the Generic System case's Lifetime and Degradation page, verify that the AC degradation rate is appropriate for your project. If you modeled degradation separately for each subsystem, you should set the Generic System's degradation rate to zero.

14. On the Generic System case's System Costs page, make sure the total installed cost and operation and maintenance costs are for the entire project. You can use the Plant Cost to enter the total system installed cost and set all of the other capital cost inputs to zero.

15. Click Simulate in the Generic System case. These results are the results for the combined system.

[cpaulgilman]

Fixed in fac8aec

[cpaulgilman]

Combine cases is now implemented as an option on the Generic System and Generic Battery Power Plant input page: #706