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Importing a Load from a Time-series File

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You can import a load from a time-series file using one of several formats that HOMER Grid recognizes.

Tip: You can import data with any time step down to one minute. HOMER detects the time step based on the number of rows in the file. For example, if the data file contains 8760 lines, HOMER assumes it is hourly data. If the data file contains 35,040 lines, HOMER assumes it is 15-minute interval data.


Meter data, measured at the project site location, is the most accurate information to use when modeling in HOMER Grid.


To import a load from a time-series file, select Electric Load or Non-critical under Outages.


Two options are available: ‘Import’ or ‘Import and Edit’.


HOMER Grid can recognize several layouts of a .csv file, as listed in the accepted format section below.


The import function requires having data that represents a single year, starting January 1st. Any time-step is accepted as long as the data is a multiple of 8760. If your data contains a leap year, you may want to use ‘import and edit’ or delete the first or last day of the year.


Once you have imported, identify which year this data was taken so that the load profiles weekday and weekend patterns will be correctly taken into account. This will have an impact on the results if there are variations in tariff price between weekends and weekdays.


Imported Data information



Import and Edit


HOMER Grid can recognize several layouts of a .csv file, as listed in the accepted format section below.


‘Import and Edit’ will allow for importing more than a year’s-worth of data and gives the option to fill in gaps in the data with a linear extrapolation between two points or to fill in the gaps in the data with zeros. These gaps in data can stem from meter failures.


Specify the Time step (minutes) with the drop down menu.


Import and edit


You can mark gaps if you select the (>) as shown below. 


Mark gaps

Accepted Formats


The following are descriptions of the formats HOMER recognizes: 1) Two Column Format, 2) Three Column Format, 3) Green Button Format, 4) Utility API Format, 5) Day By Row, and 6) Single Column of Values.  


Option 1: Two Column Format



Option 2: Three-column Format




Option 3: Green Button Format



Option 4: Utility API Format


Option 5: Day By Row



Option 6: Single Column of Values

The data file must contain a single value on each line, where each line corresponds to one time step. Each value in the file represents the average load (in kW) for that time step. The first time step starts at midnight on Monday, January 1st. The following is an example input file.


Tip: You can find templates for all 6 acceptable load formats here.

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