system
Given the following post, respond as if you're commenting on Reddit:
human
[Stargate] Where do the stargates draw their energy from?

OK, I know about the DHDs. There is probably a power source here. But how can it last for millions of years? SGC spends a huge portion of the US budget just for dialing the gate. Why couldn't they, say, go to some planet, open up the DHD, take the power source out and fly off on a ship?

Also, if it can last for that long, it would be close to a ZPM. That would solve a lot of their problems.

Or did they at least say at some point, if DHDs recharge somehow, for example from the environment (meaning geothermal, solar, wind)?
gpt
The DHDs do actually last a VERY long time. They do eventually run out of power, the Antarctic DHD was close to burning out when it was discovered, its estimated to be the oldest DHD. Nothing is stopping anybody from moving a DHD, in fact we see it done. But it was designed specifically for powering and updating the gates. It's not very useful outside of that context. 

Besides, anybody really able to harness a DHD can do better.