A dam produces 250W/m^2 of electricity. It composed of 7x10^9kg of concrete. Concrete requires 1MJ of energy to produce per kg. How much energy did it take to produce the dam? How long is the 'energy payback time" for the dam?

Question

anonymous · Answer

a) 7*10^9  MJ
b)  7*10^9*10^6/(250*A*3600*24)   days ... here A is the area of the dam in m^2

anonymous · Answer

But the area of the dam is not given, how should i calculate it?

anonymous · Answer

well then take it as 1 ... though area of the dam should be given ...

anonymous · Answer

Ok, well the second part of the question the area was given which is 274mi^2 and the efficiency is 12%.... back to the question a would be answer for the energy right??

Thanks so much Shaan!