one can calculate how much sunlight falls on a square meter, anywhere in
the world, over an average day or a year.We will use an average value of 4 kilowatt-hrs
(kWh) perm2 per day to represent a conservative worldwide average. Now, a typical
PV module is approximately 10% efficient in converting the sunlight into electricity,
so every square meter of PV module produces, on average, 4 × 0.1 = 0.4 kWh of
electrical energy per day