Simulation failure/error message and demand charge question

Hello,

I imported one year of 15-minute electric load data into SAM where I intend to use the detailed model to analyze various sizes of PV and battery combinations, resulting in 8,760 hours of data. When I try to run the model simulation I get this error message:

"exec fail(pvsamv1): electric load profile must have same number of values as weather file, or 8760
Simulation pvsamv1 failed."

How do I set up the load data (or modify weather data) to allow the simulation to run? Does the fix mean that I'll lose demand charges based on the 15-min load data? Also, how can I confirm that SAM is estimating demand charges based on the utility rate and load data?

Thanks a lot!

Dale Lyons

Dear Dale,

That message means that the time step of your weather file (60 minutes) does not match the time step of your load data (15-minutes).

Ideally you should use weather data that matches your load data, because it is likely that the load is affected by the weather data. For example, air conditioning loads increase with solar irradiance and temperature.

If your load data is from a particular year, let's say 2013, then you could download a single-year weather file from the NSRDB for 2013 instead of using the TMY file.

We have developed an LK script to convert your hourly weather file to a 15-minute weather file. That will at least allow you to run a simulation and get some results. To use the script, download it from the Samples page (it should be Item #2):

sam.nrel.gov/samples

To run the script, in SAM go to File, Open script, and then click Run at the top of the script editor.

Best regards,
Paul.

Worked like a charm! Thanks!
Dale