[holycrapwhodat]

Our universe is a closed system. We cannot change its overall heat content. We can only move heat around within it.

Without tapping into another universe - which we're nowhere close to being able to even theorize about - all we have the ability to do is create a localized heating crisis within our universe.

[malfist]

In about 5 billion years, we'll have a really bad localized heating crisis in our solar system.

[pixl97]

The universe is busy doing this itself. Eventually we use up all the low entropy states and end up in high entropy states where we can no longer extract useful energy.