The projected baseline energy use is calculated by an energy model during the design phase. All ECMs are removed from the model and this energy data becomes the baseline to determine energy savings when compared to the actual energy use. According to Opti

The projected baseline energy use is calculated by an energy model during the design phase. All ECMs are removed from the model and this energy data becomes the baseline to determine energy savings when compared to the actual energy use. According to Option D of IPMVP III, the model must be calibrated so it is ready to be used after one year of data collection.