If we waste so much energy that the Earth gets brighter than the Sun, yeah, we can replace all the helium we use. If we crack fusion, it's more likely that we'

If we waste so much energy that the Earth gets brighter than the Sun, yeah, we can replace all the helium we use. If we crack fusion, it's more likely that we'll use the free energy to mine it in space. If we have to make it on Earth, we'll probably do it through fission.