system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible to harness gravity as a means of producing energy?
gpt
Sure - pile up a bunch of water behind a wall and only let it out through a hole so it has to push past a turbine on the way.  

Hydroelectric dams are the most straightforward use of gravity for energy production. Similar methods using a pump followed by a generator are use for energy storage, too.