Trough system power estimates

Struggling to attach...

First question is:

I am using the SAM 2020.11.29 version, startup is still an issue.

At startup, the efficiency is given to be really low. If I use however values of efficiency from the next timestep I seem to get closer values. In your example:

If I use the first row, startup:

(218.4 - 62.36) x 0.199=30.97 this is less than the software generated gross output of 61.85. 
However if I use 0.397 for efficiency (from next row)
(218.4 - 62.36) x 0.397=61.85 I obtain a very similar value.

do you know why this is the case? why are we getting strange values for efficiency while the gross output is computed at a higher efficiency assumption?

Second question is:

Can I confirm that the software does not consider any boiler back-up in the energy computations (I have seen some grid interconnections but not fossil fuel/boiler) ? is that physically possible?

Regards

Hi Jessica,

Please see the explanation here for an explanation of the efficiency during startup hours: github.com/NREL/SAM/issues/598 . We will fix the reported efficiency values in the next update to SAM.

The physical trough and power tower models do not have a backup fossil boiler.

Best regards,
Paul.