It's made clear from the start that the Machines that run the Matrix are powered from the heat produced by humans.

How is Zion powered without human batteries? And, since the Machines are aware of Zion and have apparently broken in before, in previous cycles, why can't the Machines use the same type of power source instead of requiring humans hooked up to the Matrix and in the "farms?"

  • Didn't the Wachowskis, after acknowledging the "human batteries" motive was flawed, devise a whole new reason for the existence of the Matrix? (Can't find a reference now, otherwise I would write a proper answer)
    – Andres F.
    Commented Feb 29, 2012 at 17:32
  • Maybe a thing very similar to the thing that powers Bartertown in "Mad Max Beyond Thunderdome" ;-) Commented Apr 5, 2013 at 5:21
  • Like @AndresF. says, the whole "human battery" concept was the weak point of the plot; I wouldn't spend too much time trying to poke holes where's there already a gaping one. Commented Dec 6, 2014 at 2:35
  • I'd go one step more, @PaulDraper. I'd say the plot was one whole collection of weak points.
    – Tango
    Commented Dec 8, 2014 at 1:10

3 Answers 3


It's mentioned that Zion is very deep in the Earth, thus insinuating that it's powered by geothermal energy. Here's a relevant quote from the first movie:

Tank: If the war was over tomorrow, Zion is where the party would be.

Neo: It's a city?

Tank: The last human city. The only place we have left.

Neo: Where is it?

Tank: Deep underground, near the earth's core where it's still warm.

Why the machines didn't also take advantage of such a cost effective, reliable, and sustainable energy source is unclear, especially since they obviously have advanced drilling technology. They reached Zion repeatedly, after all!

I guess we are to assume that the biological source of power from humans is somehow (waves hands) more cost effective and sustainable than geothermal energy, although I wouldn't categorize it as being more reliable given all the problems they had with their "zoo"/power plant.

  • Well for one, geothermal is limited, batteries is theoretically indefinitely expandable.
    – Ashterothi
    Commented Feb 29, 2012 at 17:18
  • 1
    @Pyrodante Both are limited. Where do the machines get the energy to recharge their human batteries? I can't remember now if in Matrix the Earth is assumed to be a closed system, because if it is, that's a serious flaw!
    – Andres F.
    Commented Feb 29, 2012 at 17:29
  • 6
    The first Matrix movie also mentions that the machines use "a form of fusion" in addition to the bioelectric/biothermal energy of humans. The short of it is that there are many things the machines could use for power besides humans. The sun's still up there; if a hovercraft can breach it, the machines could send solar panels up on balloons. The use of humans keeps humans in the story, because that's the whole point; humans are being used as batteries. If the machines didn't need us, there would be no Matrix and no story.
    – KeithS
    Commented Feb 29, 2012 at 17:44
  • 2
    @Pyrodante It's a glaring error! Surely to liquify humans you must spend energy (how do you power your liquifier?). So if your only source of energy is humans, and when they die you must spend even more energy "recycling" them, your resources must be rapidly dwindling!
    – Andres F.
    Commented Feb 29, 2012 at 20:06
  • 1
    I personally feel this simply demonstrates that the robots were proving a point. They couldn't make peace with the humans, so enslaving them like they were once enslaves was a fitting irony
    – Ashterothi
    Commented Feb 29, 2012 at 20:14

If you subscribe to the Matrix within a Matrix theory, then technically humans power Zion too.

  • With that theory humans would power the Zion simulation, but within the simulation, what would the simulated power source be? My head hurts now...
    – gnovice
    Commented Feb 29, 2012 at 18:19
  • 1
    @gnovice - for that I would assume your answer is right, geothermal. A power source that is technically limited, but in the span of a human life would seem almost unlimited. So it would feel right to those in the simulation, which is what Zion is all about, giving those who reject the Matrix something that "feels" right.
    – Justin C
    Commented Feb 29, 2012 at 18:22
  • @gnovice also let's remember that if Zion simply exists within another layer of simulation, the system controls all empirical data and decay, so even if geothermal might not ACTUALLY(not saying it couldn't) power Zion, all the data the humans were able to see would point to that it could
    – Devon M
    Commented Jan 30, 2015 at 9:23

An MIT study from 2006 estimated there's about 13 000 Zettajoules of Geothermal energy in the Earth. That was before we discovered with recent instruments that the core is actually hotter... which might imply an even bigger number than 13 000 Zettajoules.

At any rate, that same study indicated that we had the technology in 2006 to tap into 200 Zettajoules of power, with the ability to expand to 2000 Zettajoules in the future with enhancements to the technology in question.

Human civilization currently uses about 0.5 Zettajoules (but estimating that 1 third of Humanity doesn't have electricity... in order to provide ALL Humans with power, that number would likely go up to about 0.65 Zettajoules).

I would think the machines would be emphasizing technical efficiency (doing more with less). Ergo, they'd likely find even 200 Zettajoules 'too much', but you never know... since this is supposed to be closer to 2199 - and most scifi seems to not understand the concept of 'doing more with less' (technical efficiency).

The 'human battery' concept really doesn't fly. The machines obviously have access to very efficient drilling technology, so they could easily go all the way down very close to the core and tap it directly (instant and nearly inexhaustible source of power which is renewable to boot).

The machines were at one point described as being powered by solar... but Humans then darkened the sky.

Depending on how many Humans they grow... I don't quite think that even at 7.2 billion, you'd be able to generate the amount of power that is equivalent to what is produced by the Earth's core.

  • 2
    This is basically a glorified rant rather than an answer to the question asked.
    – Valorum
    Commented Aug 7, 2015 at 22:16
  • 1) Pretty much anyone on this site can tell you the human battery concept is dead, so that's not necessary to mention. 2)You give us a lot of details, then say, "I would think..." so you're basically drawing a conclusion with nothing to back it up. 3) It really seems like you're more interested in talking about this possible energy source than actually answering the question.
    – Tango
    Commented Aug 8, 2015 at 6:32
  • So, I provide the background context based on real life study showing that there's a superior energy source available to the machines to use and then I get rated down because of extrapolating from that (like many others have done in this thread and didn't get rated down?). Wow... no, my response was supposed to provide sufficient context for available energy source for the machines. As for Zion, it was never stated on what the city runs, but one would imagine that Humans would be quite ignorant not to use Geothermal for energy that close to the core anyway
    – Deks
    Commented Aug 8, 2015 at 9:49

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