calculating solar power output.

hello I'm writing about a off the gird solar power using solar photovoltaic system. I have explained how the system works along with single cells. the advantage and disadvantages of using solar enegy.

I wanted to try and calculate the solar power output and its efficiency. I cant seen to find a good formula to use!

anyone help!

so far ive fould these websites

http://photovoltaic-software.com/PV-solar-energy-calculation.php

http://www.windandsun.co.uk/information/solar-power/calculating-pv.aspx#

but cants seem to work it out!

thanks

The global formula to estimate the electricity generated in output of a photovoltaic system is :

E = A * r * H * PR

E = Energy (kWh)
A = Total solar panel Area (m²)
r = solar panel yield (%)
H = Annual average solar radiation on tilted panels (shadings not included)
PR = Performance ratio, coefficient for losses (range between 0.5 and 0.9, default value = 0.75)