Nuclear fusion only takes place deep, deep, in the core of the sun. The specific power of the sun is about the same as rotting bale of hay, about quarter of a watt per meter cubed.
A cubic meter of hay has surface area of 6 meters so the power per square meter is 0.25/6 = 0.042 watts per square meter.
The sun has a volume of 1.412 x 10^27 cubic meters and a surface area of 6.09×10^18 square meters, or roughly 2.32 x 10^8 cubic meters per square meter of surface area or 6 x 10^7 watts per square meter, or roughly a billion times more than the hay bale per square meter.