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HOMER Grid 1.3

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Generator Library

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To access the Generator Library, select the Library icon library icon found on the upper right hand corner of the main window. Choose the Generator component tab as highlighted below to view your options.

generator library


You may select the View and Edit Generator Library to view or edit one of the default generators or choose to create a new component using the Fixed Capacity Generator template or Size-your-own Generator template.


Click View and Edit Generator Library to see the list of default generators. Click on a generator component from the list to view details. You may also create a new component by copying an existing entry and changing the specifications. See the Library section of the help for instructions.


The following tabs contain inputs that are common across generator models:










A unique name used to identify this generator.


A short, distinctive name to identify this generator on the schematic and results. There is no specific limit on the abbreviation length, but long abbreviated names do not fit well on the schematic or results.


An optional field used to specify the manufacturer of the generator.


An optional field to provide text for a web link for the generator.


The actual web address of the link defined in the "Website" input.


An optional field used for additional specifications, manufacturer contact information, or anything noteworthy.

Electrical bus

The type of generator output current (alternating current or direct current).

Lifetime (Operating Hours)

The number of hours the generator can operate before needing replacement.

Minimum Load Ratio

The minimum allowable load on the generator expressed as a percentage of its capacity.

Heat Recovery Ratio

The percentage of waste heat that can be used to serve the thermal load. If you are not modeling a thermal load or you do not intend to recover waste heat from the generator, set this to zero. This input requires the Combined Heat and Power Module.

Minimum Run Time

After the dispatch starts the generator, it remains on for this duration or longer.


You can set the generator efficiency and calculate the fuel curve from specification data under the Fuel tab. Select the generator's fuel from the drop-down menu at the top of the page. You can enter data points of fuel consumption and output power in the fuel curve table. HOMER calculates a best-fit fuel curve from the data. HOMER uses the value in the "Reference generator capacity" entry when calculating the "Intercept coefficient." You can also input the fuel curve coefficients manually.


The fuel consumption versus power is plotted in the top chart. The efficiency versus power output is plotted in the lower chart. If you've specified a non-zero heat recovery ratio, the thermal efficiency and total (thermal + electrical) efficiency are also plotted on the efficiency chart.


In the Schedule tab, you can specify a default operating schedule for the generator. When adding the generator to your model, you can use a similar page to modify the default operating schedule for the specific installation. The Schedule subsection under Generator in the help describes how to define a generator operating schedule.


You can define the frequency, cost, and down-time of generator maintenance events in the Generator Maintenance Schedule. The Maintenance tab allows you to define the default Maintenance Schedule for the Generator Component. When you add the Generator to a model, you can modify the Maintenance Schedule from the default schedule you define here. The inputs are the same for the Generator Maintenance Schedule for the Generator Component under Design. See the Generator section of the help for instructions and details on defining a Generator Maintenance Schedule.


The Emissions tab on the Generator page gives you access to the following emissions factors input variables:



Carbon Monoxide

The quantity of carbon monoxide emitted per unit of fuel consumed by the generator, in g/L*

Unburned Hydrocarbons

The quantity of unburned hydrocarbons emitted per unit of fuel consumed by the generator, in g/L*

Particulate Matter

The quantity of particulate matter emitted per unit of fuel consumed by the generator, in g/L*

Proportion of Fuel Sulfur Converted to PM

The fraction of the sulfur in the fuel that is emitted as particulate matter (the rest is emitted as sulfur dioxide), in %

Nitrogen Oxides

The quantity of nitrogen oxides emitted per unit of fuel consumed by the generator, in g/L*

*These units are in g/m3 for fuels that are measured in m3, and g/kg for fuels measured in kg.

Note: To the right of each numerical input is a sensitivity button (shots_sensitivity-button) that allows you to do a sensitivity analysis on that variable. For more information, see Why Would I Do a Sensitivity Analysis?


See also


The Homer Support site has a searchable knowledgebase and additional support options. HOMER Online contains the latest information on model updates, as well as sample files, resource data, and contact information. ©2017 HOMER Energy, LLC