In fact, HOMER can model grid extension in a simple way, and compare its cost with the cost of a stand-alone system. To model grid extension, click the Add/Remove button and choose ‘Compare stand-alone system to grid extension’. Then a button labelled ‘Grid extension’ will appear below the schematic. That button brings up a window where you can enter the costs of grid extension. Then when you double click on a system in the optimization results list, the Simulation Results window will contain a Grid tab showing the breakeven grid extension distance and a graph comparing the cost of grid extension with the stand-alone system.
For details and to see the equation for the breakeven grid extension distance, please look up ‘grid extension’ in the index of the Help system.