Solar Retrofit Modeling

Solar Retrofit Modeling

Solar Retrofit Modeling

Starting in March 2025, Keystone Designer supports modeling solar retrofits. A solar retrofit is a scenario where there is an existing solar array, and project stakeholders want to explore adding additional solar and/or an energy storage system.

Interval data for a solar retrofit will likely have negative kW values due to overproduction. Keystone Designer will interpret the negative values from the array as generation to be used to charge the modeled energy storage system, or to add to solar production if modeling additional solar equipment. If you wish to model a solar retrofit but the interval data has no negative values, reach out to your contact at Fortress Power.

Changes to Scenario Editor

Since Designer interprets negative load values as generation from the existing array, scenarios modeled with negative load values and energy storage alone will have the ability to set 100% Renewable Charging to true. 

Changes to Scenario Results

Baseline Energy Credits will now appear on the "Utility Bill Savings" section of the scenario results:


Energy Credits will appear as positive in the report. If a retrofit scenario is modeled with an energy storage system, the storage may charge from any export coming from the original array. Due to this potential charging, the projected Energy Credits may be less than the baseline:


In this example, the energy credits were reduced due to energy storage charging, so there are less credits in the projected results. The savings portion of this report will then show negative values to show the loss in energy credits: 



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