Eventually, if the population continues to increase at its present rate, or even faster given that each couple (man and woman) can produce a lot of children and those children can do the same, we will be at another crises (sp). Each new individual will require food, shelter, etc and this will tax the Earth's resources even more so than it already does today. We would eventually run out of arriable (sp) land and oxygen producing trees. Wars would inevitably occur and with all that free energy warships, warplanes, tanks and free energy bombs would be used.
Free Energy is only part of the solution, not "THE SOLUTION". As we would have to manage the land, animals and food producing plants we would by necessity have to manage the Earth's human population. Try to convince people that they cannot have more than one child or even none at all unless they met some kind of "certain" criteria and see how well that 'one' goes over with the world populous.
Just a thought.