1. The problem statement, all variables and given/known data Suppose we succeed in building a H-->He fusion reactor. How much hydrogen would have to be converted per second to supply the world's electricity consumption of 10^13kwh. 2. Relevant equations This is what I am looking for, I think i can figure it out once I know the appropriate equation 3. The attempt at a solution My attempt is to first figure out the energy output of when hydrogen turns into helium. So i take 4 hydrogen at 1.00794 amu a piece, then 1 helium at 4.002602 amu and subtract the totals. Thus: (1.00794 x4) - 4.002602 = .029158 amu I assume this number is the mass converted to energy? From my book 1g of H--> HE is 650,000,000 kw of energy output (converted from 6.5x10^18 erg) So from there couldnt I figure this problem out by just finding how many seconds are in a year. Then dividing 10^13kwh by the total amount of seconds, then with knowing the output of 1g convert my Kw per second into amount of material? I would like to know if im on the right track or if I am disregarding something important (efficiency isn't involved).