Take a look at a recent residential solar installation My Generation Energy completed in Harwich, Massachusetts.  This is an addition to an existing 5.4 kW solar array My Generation Energy installed on the other side of the roof. The original system has produced over 27 Megawatt hours of electricity!!  This new solar array is a 4.2 kW system and will add over 5 megawatt hours of green electricity to the annual production.