Solar Power Density & Energy Conversion Efficiency     Assumptions
 

     "If the extraterrestrial solar radiation is 1367 watts per square meter (the value when the 
     Earth–Sun distance is 1 astronomical unit), then the direct sunlight at Earth's surface
     when the Sun is at the zenith is about 1050 W/m2, but the total amount (direct and indirect
     from the atmosphere) hitting the ground is around 1120 W/m2.[3]"

              https://en.wikipedia.org/wiki/Sunlight 

The Average Solar Power Density for PV solar panels is considered to be 1,000 W /sq. m    
              http://www.solstats.com/blog/solar-energy/what-is-solar-peak-power/

PV Panel Energy Conversion Efficiency: 
The Shockley-Queisser limit for the efficiency of a single-junction solar cell under unconcentrated sunlight is 34%

 

     "There are a few solar panels available that are exceeding 19% efficiency."

               https://en.wikipedia.org/wiki/Solar_panel

 

Average solar power in compared to electrical energy out = 20% Efficiency  (2015) 

              https://en.wikipedia.org/wiki/Solar_cell_efficiency

 

Hence, the solar radiation converted by a PV Solar Panel is (1000 W / sq. m X 20%) = 200 Watts per sq. m

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