Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I think the simplest way to do it is in post-processing. You can define output variables for electric generation and consumption on an hourly level, import the csv results to excel and calculate the hourly surplus there.
Or you can use this output variable: Average,Facility Total Surplus Electric Power [W], see page 2147 in the I/O reference.
