Feature Request: Set start date

I'd like to compare the simulated results with my actual production.  To make that easier, it would be nice if there was a way to set the starting date time of the simulation, instead of defaulting to January 1 00:00.

I'd assume that there wouldn't be a large difference and so doing a ballpark comparison of the current simulated vs. actual data is good enough. It seems like it would be a relatively easy change though.

Hi Walt,

Can you tell me more about what you are trying to do? Do you have your own weather data, or are you hoping to compare the measured production data from SAM results with a weather file downloaded from the NSRDB?

SAM reads the time stamp data from the weather file to calculate the sun angle in each time step, so if you are using your own weather data, you can have it start on any day of the year, as long as the file contains one year's worth of data.

That approach should work if you are only using the performance model. If you are using a financial model that includes time-dependent features like time-of-use electricity rates or time-of-delivery PPA price multipliers, the financial model assumes that the first time step is on Monday, January 1 for those calculations.

We do have plans to add some flexibility to SAM's time conventions -- it is a little more complicated than it might seem.

Best regards,
Paul.

Hi Paul,

What I'd like to do is compare my actual generation vs. what the simulation says I should be generating. I think this could be useful to ensure that there aren't any problems with my system.   

I understand that the level of precision isn't going to be that good and so using historical weather data is probably fine for this purpose (though I suppose it could be improved by getting actual weather data for the months in question).