I don't get it. Why would a new form of energy need a new heat sink? Wouldn't any energy we can realistically generate be a drop in the bucket compared to what

I don't get it. Why would a new form of energy need a new heat sink? Wouldn't any energy we can realistically generate be a drop in the bucket compared to what the Sun throws at us every second? And even if not, what would a heat sink do about it? I think I'm missing something.