Fossil fill for CSP systems

I just wanted to confirm that the fossil backup system for CSP in SAM is configured to allow fossil back-up of up to 100% of nameplate capacity if necessary. In other words a 50 MW solar plant can run entirely on fossil backup and still produce 46-50 MW of energy to the grid if there are no solar resources available.
Yes. Although the fossil fill model in SAM is intended to model a backup system that supplements solar energy with natural gas, it is possible to model a system that generates power at the system's nameplate capacity using only fossil backup during times when there is no solar energy.
For example, if you start with the default physical trough system, and on the Thermal Storage page, change the Fossil Fill fraction to 1 for Period 1, and then assign Period 1 to all hours in the weekday and weekend schedules as in the screenshot below, in the Results you will see that the hourly power generated by system is constant over the year. The small variation in power output that you see is due to parasitic and other operating losses.

Best regards,

Paul.