One Minute Solar Data Simulation

I was wondering if SAM can simulate output from solar PV at one minute intervals using our own solar data (which is at one minute resolution). Is there any established solar data sets at one minute intervals?
SAM's photovoltaic models and the physical trough model can run with weather data up to one minute resolution. However, at one-minute time steps the models may not accurately represent the thermal characteristics of the system. In general, the model algorithms are most suitable for hourly up to to 10- or 15-minute simulation time steps.
I am not aware of a free source of solar resource data at one-minute resolution.
Best regards,

Paul.

Good day,

Which versions of SAM provide this modelling capability at lower timesteps?

regards
Paul

The latest version, SAM 2015.1.30, supports subhourly simulations for the detailed photovoltaic, PVWatts, HCPV, and physical trough models, and will run with a weather file with up to one-minute temporal resolution in the SAM CSV format.

SAM 2014.1.14 supports subhourly simulations with the physical trough model, and requires a weather file in the SMW format.

Best regards,
Paul.

Hi Paul,
Thanks for the details.
With regards to SAM 2014.1.14, is the physical trough the only model that supports sub-hourly simulations? I'm interested in running other CSP models, as well as WP, PVFP and PVW.
If SAM (2014 or 2015) is presented with sub-hourly data, does it automatically use it because I didn't see any settings in the interface for this in SAM 2014.1.14. Maybe I should be looking in the latest 2015 release?
Is is possible generate sub-hourly output data from any of these models? I posted a question previously ( sam.nrel.gov/node/69311 ) as to the best why I can see to do this, but perhaps there is an easier way?
Thanks for you help.
regards Paul

Dear Paul,
Yes. In SAM 2014.1.14, only the physical trough model supports subhourly simulations, and subhourly simulations require the special SMW weather file format. In that and earlier versions, there is a time step setting on the Simulator Options page. That setting is only active for performance models that can run with subhourly weather data -- you have to make sure the setting matches the weather file time step. You will notice that the setting is active for the other CSP models, but we only tested the physical trough model for subhourly simulations. In my quick test with the power tower model and a 15-minute weather file, the simulation failed. The data viewer in SAM 2014.1.14 and older versions does not support subhourly simulations: It only displays the first 8,760 rows of data, so you have to use different software to view the output files.
In the current version (SAM 2015.1.30), SAM determines the simulation time step automatically from the weather file by counting the number of rows in the file. There is no time step setting. The data viewer in this version supports subhourly data, so you can view the data in SAM.
Here are two other threads that should help shed some more light on these topics:
Time Step for SAM Model Simulations
Time Step -- Accuracy of the Simulation
Best regards,

Paul.

Dear Paul,

I am using the Parabolic Trough physical model in SAM 2015.6.30, in order to simulate a solar thermal plant. I have created my own weather CSV. files for both an 1-minute and an 1-hour simulation. I have run the simulation for both time steps and I get different results. I have checked the field inlet and outlet temperatures and compared it to the real measured data (minute values and generated hourly mean values, respectively) and they correlate much better by the 1-hour calculation than by the 1-minute one. Also the yearly energy gains are different.
So, in general, does the 1-minute time step simulation lead to less accurate results? Do you think, it would be better, if I finally do the 1-hour simulation?

Thanks for your help.

Best regards,
Alex