Natural Gas Consumption by Auxiliary Boiler

Dear Paul,
In CSP Trough plants, due to the new law (here in Spain) it is not allowed/paid to use Natural Gas from last January 2013 to produce electrical energy so that the strategy used by SAM will be not completely usefull.
Based on these comments/law it will only be possible to use Gas by:
- MAIN HEATERS (for HTF and Salts antifreeze)
- AUXILIARY HEATER (for turbine and turbogroup sealing)
Problems of model:
In first place, SAM use Gas to produce electricity (not allowed), how to avoid?Puting a fossil fill fraction of "0"?
Secondly, it doesn´t exist an Auxiliary Boiler equipment, and this will be the main Natural Gas consumption in the plant, probably around 70%. How to model this equipment and consumption?

Thank you very much for your help.

Hello,

In SAM's CSP models, "fossil backup" calculates the energy required to supplement solar energy in order to maintain the solar field outlet temperature at its design point. The financial model accounts for the cost of using natural gas to meet that energy requirement based on the LHV efficiency you specify on the Power Cycle page, and the fuel cost you specify on the O&M page.

SAM does not explicitly model the equipment that converts the gas energy into thermal energy, and it does not model gas heaters in other parts of the system that might be used to provide supplemental heat. It does model solar field antifreeze heating requirements to maintain the solar field HTF at or above the freeze protection temperature that you specify, but assumes that the heat is provided by electric heat trace equipment.

By setting the fossil fill fraction to zero for all periods (on the Thermal Storage page), you model a system with no fossil fuel consumption.

Best regards,
Paul.