HOMER Knowledge Base
How do you size generators in HOMER Pro?
Product: HOMER Pro 3.11.5
There are many different approaches to sizing a genset.
Autosize Genset:
The autosize genset uses the method described in it’s description:
“This generator automatically sizes itself to meet the load. The capacity of the generator will be the smallest that will produce no capacity shortage in all sensitivity cases and future years (if using a Multi-Year analysis). It also adjusts its fuel curve to match its size.”
Fixed Capacity Genset:
These gensets, as the name suggests, have fixed rated capacity. You can change the capacity of these gensets through the component library within HOMER Pro. You can find the steps to do it here.
Size-your-own Genset:
Size-your-own gensets let you choose multiple sizes that you would like to consider in your model. In the search space table, enter the sizes of the generator you want HOMER to evaluate as it searches for the optimal system. HOMER uses the information you entered in the Generator Cost table to calculate the costs of each generator size, interpolating and extrapolating as necessary.
By default, after you add the generator component, HOMER only considers systems that include a generator. If you want HOMER to consider systems both with and without a generator, be sure to include zero in the search space. System designers commonly specify a single nonzero generator size, one large enough to adequately serve the peak load. When given a choice of generator sizes, HOMER invariably chooses the smallest one that meets the maximum annual capacity shortage constraint because smaller generators typically cost less to operate than larger generators.
There are many different approaches to sizing a genset.
Autosize Genset:
The autosize genset uses the method described in it’s description:
“This generator automatically sizes itself to meet the load. The capacity of the generator will be the smallest that will produce no capacity shortage in all sensitivity cases and future years (if using a Multi-Year analysis). It also adjusts its fuel curve to match its size.”
Fixed Capacity Genset:
These gensets, as the name suggests, have fixed rated capacity. You can change the capacity of these gensets through the component library within HOMER Pro. You can find the steps to do it here.
Size-your-own Genset:
Size-your-own gensets let you choose multiple sizes that you would like to consider in your model. In the search space table, enter the sizes of the generator you want HOMER to evaluate as it searches for the optimal system. HOMER uses the information you entered in the Generator Cost table to calculate the costs of each generator size, interpolating and extrapolating as necessary.
By default, after you add the generator component, HOMER only considers systems that include a generator. If you want HOMER to consider systems both with and without a generator, be sure to include zero in the search space. System designers commonly specify a single nonzero generator size, one large enough to adequately serve the peak load. When given a choice of generator sizes, HOMER invariably chooses the smallest one that meets the maximum annual capacity shortage constraint because smaller generators typically cost less to operate than larger generators.