Negatives Value for System Power Generated

Hello,

I am using SAM in order to analyze a PV+Storage system, and I find this incoherence in the results:  at some hours at night I get as a result negative Sytem Power Generated. I am attaching a image so you can see it, it is true that the value is really low so it will not really affect to the results, nevertheless, in other study that I worked on, I found this negative value much higher and I would like to fix it.

Looking forward for your help, 

Thanks,
Antonio

Hi Antonio,

For a PV system, the negative power values at night are for the inverter's night-time consumption, which is based on the Power use at night input on the Inverter page.

Best regards,
Paul.

Hi Paul,

what about nagative values for system power generated in trough model?

kind regards
Joey

Hi Joey,

For the CSP systems, negative generation represents power required by the system itself when it is not generating power. This can be power for pumps, heaters, or other equipment that work to maintain HTF temperatures and flow rates.

The Plant Energy Consumption inputs on the System Control page and the minimum HTF temperatures and mass flow rates specified on the Solar Field and Thermal Storage page determine how much energy is required by the system.

You can see some of these values in the results, for example:

Parasitic power fixed load
Parasitic power condenser operation
Parasitic power TES and Cycle HTF pump
Parasitic power generation-dependent load
Field freeze protection required
Field htf pumping power

Note that SAM applies the system availability loss from the System Control page to some of these values.

Best regards,
Paul.

Hi Paul,
understood, thank you.
kind regards
Joey