[RE-wrenches] Percent of DC capacity that is inverted to AC kWh?

[Christopher Warfel]

We reached the cap for the utility where we work for renewable energy 
interconnection until there is Rhode Island State legislative action to 
raise the cap.  I am going through the utility records as they are not 
completely accurate. Does anyone know of a reference that can point to 
what percentage of dc capacity actually comes out as ac power.  Looking 
at various inefficiencies and the battery load, I am estimating about a 
15% "loss".  I realize a lot depends upon the design, and the state of 
the batteries, but I am just looking for sounding board opinions, or a 
reference if available. Thank you, Chris