Hi all,
I am modeling a portfolio of buildings with on-site PV generation. Some of the buildings have rooftop PV, and others have ground-mount PV next to the building. I am modeling the rooftop PV using the "Add Rooftop PV" measure, and modeling the ground-mount PV by specifying a shading surface of the desired dimensions in Sketchup, and then using the "Add Simple PV to Specified Shading Surface" measure.
I have noticed drastically different electricity generation values from these two measures, so I performed an experiment on the same surface area, with the same parameters (18% cell efficiency, 75% of included surface area with PV) . I used the add Rooftop PV measure to a building with a rooftop area of 15,000 sqft, and the OpenStudio model shows an annual generation of 473,580 kWh/yr. When I specified a 15,000 sqft as a shading area, and applied "Add Simple PV to specified shading surface," the model shows generation of 70,464 kWh/yr.
Does anyone know what is going on here?
