Modifying Facility Peak Demand

We're completing a PV model and financial analysis for an institutional facility, and have monthly electrical consumption and demand data. I've modified the monthly load summary for energy consumption (kWh), but the peak usage (kW) is higher than is showing in SAM by a factor of between 1.5 and 2.5, depending on month. Also, I've tried using the NREL OpenEI building load database to find a matching profile, but can't find any that match.

Is there any way in SAM to modify the peak demand numbers? This plays fairly heavily into the financial outputs.

Thank you!

Hi Ted,

When you use the "Normalize supplied load profile to monthly electricity bill data" option, SAM scales the underlying hourly or subhourly data for each month so that the sum of the values add up to the monthly totals you enter. You can see that by clicking the View Load Data button. The data viewer shows the scaled data in orange and the original data in blue. The resulting peaks depend on the underlying data.

If you need the peaks to be specific values, you'll have to edit the load data to change the peak for each month. You can export the scaled data from the data viewer by right-clicking the graph (be sure to zoom out so the entire year's worth of data is visible). Then you can use Excel or some other method to set the monthly peaks. The data is exported with hour numbers rather than dates, so this table might help convert the hour numbers to dates:



To get the edited data back into SAM, you can select and copy an 8760 column of data and paste it into the Energy Usage table (click Edit array to open it).

Best regards,
Paul.