Earlier quoted context omitted.
For as so long we have a positive birthrate, we'll reach the point of using all the energy that our local sun and technology can provide. We'll have to consider population control.
There are multiple issues with this idea. First, I just don't think you can really tell that from this perspective. That's just thinking too far into the future. This sort of argument is likely to look like a Great Horse Manure Crisis of 1894 [1] to our descendants. [1]: http://www.historic-uk.com/HistoryUK/HistoryofBritain/Great-... Have you actually considered how many people it would take to use all energy that su…
It's an unimaginably large number of humans. Seven billion human beings is a drop in the bucket as far as I am concerned.
Universe is really vast, if not infinite. And when we have more people, alive, and doing meaningful things while automation takes over menial tasks, it's really going to make us tackle other problems faster, like transportation.
There's only so much matters and so many stars in the universe. Granted, they can last a stupendous long time, especially red dwarf stars.
Future technologies aren't something that can't be predicted entirely, but we can only consider the laws of physics as we know of to constrain our prediction.
Last time I check, there is no way to produce unlimited energy for eternity, no way to defeat entropy. Until that happen, we'll have to consider population control unless our numbers are stable or in decline.