Why is sub-hourly data output processing ending at "Power generated by System"

Hi
Why is the sub-hourly data output processing flow seemingly ending at "Power generated by System"?

In the processing flow, for example, from irradiance through "Power Generated by System" through "Electricity to/from Grid" through "Energy Charge with System", the last access to sub-hourly data seems to be "Power Generated by System" in the "Data" and "Time series" results tabs.

Is there a way to access the sub-hourly data for such outputs as:

Electricity to/from grid | (kWh)
Electricity from system to load | (kWh)
Electricity from grid | (kWh)
Electricity load (year 1) | (kW)
Electricity peak from grid per TOU period | (kW)
Electricity peak from system to load | (kW)
Electricity to grid | (kWh)
Electricity to/from grid peak | (kW)


As I'm entering Weather and Load at sub-hourly intervals, it would seem that such values would calculable at sub-hourly intervals.

With 1/2 hour billing and demand charges the norm for our market, detail down to 1/2 or 1/4 hour would be extremely helpful.

Thanks for a great product

Mark

Hi Mark,

Those outputs that begin with "Electricity" are results of SAM's electricity rate module, which makes calculations on an hourly basis, regardless of the simulation time step. You should see those variables listed under "Hourly Data" on the Data, Time Series and other tabs on the Results page.

It is important to understand that when you use sub-hourly weather data, SAM runs a sub-hourly simulation to calculate the power generated by system, but makes the utility bill calculation by averaging the sub-hourly kW values to calculate an hourly kWh value. For example, suppose you run a 15-minute simulation with the following results:

15-minute power generated by system for January 1 12:00 pm:
2.90695
2.92024
2.91201
2.8524

Hourly electricity from system to load (kW) for January 1 12:00 (assuming all system power goes to load) should be the average of the 15-minute values for the hour:
2.8979

SAM calculates the hourly peak electricity to/from grid (kW) for each hour as the maximum of the four 15-minute kW values.

In answering your question, I realize that SAM is not reporting enough 15-minute outputs for you to see exactly what it is doing. I'll see about fixing that for the next update.

Best regards,
Paul.

Hi Paul

Thanks for the response.
I thought that certain averaging in the transition to hourly data to must be taking place. I was hoping that you carried out these calculations at the sub-hourly level as all our billing, energy and demand, is taking place at the the 1/2 hour interval.
I think on at least kW demand reduction you may see some quite large discrepancies.
I will email an example.

Thanks
Mark

Hi Mark,

Good to know about the 1/2 hour interval. Just to be clear, for sub-hourly data (both weather and load), SAM treats the maximum of the electricity from grid (kW: load minus PV generation) values in each hour as the peak for demand charge calculation. The averaging is for the energy charge calculation.

Best regards,
Paul.