You have to compare the meteo file of energy plus and the meteo file of your building (location). maybe the beam and diffuse solar radiation is not the same. check this and tell me.
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: yusuf085225@xxxxxxxxx
Date: Sun, 26 Jun 2011 07:03:11 +0000
Subject: [EnergyPlus_Support] photovoltaic
I use BP2150S photovoltaic in modeling my building, the maximum power output is 150 W. The total photovoltaic modules I use are 736.
my question : is it common that photovoltaic can produce 6806.63 GJ electricity in my model?
and the total building energy consumption is only 1404 GJ.