Well apparently you don't use them as much as you should. The context of these quotes is the Merovingian sending out operatives to interview Raini, a former program that oversaw the fission process before she exiled and the machines switched to fusion. And Silver a known expert researcher for his opinion on if the human body could produce enough energy to fuel a city.
Raini: Oh, poo! You're no fun. All right, all right... Lemme tell you, anyone who talks up fusion is usually a pipe-dreamer. Yeah, so fusion of deuterium produces more power than fission of an equivalent amount of uranium, results in less radioactive waste... But do you know what it takes to get fusion to work? You've got to hit the Lawson triple product, you need some kind of containment: plasma, or magnetic, maybe... Well anyway, it isn't easy! I don't see why the Machines would go with fusion over fission - it's not like they're worried about polluting or anything.
Silver: No, no, no... It doesn't matter what kind of fusion they may have come up with; even if it does utilize some type of biological reaction, there's no getting around the fact that the most perfectly - and I use that term relatively - conditioned human body is only about twenty five percent energy-efficient; the units dredged out of the pods can hardly can hardly be said to be in peak physical condition. Even if they could siphon off most of the energy produced - and I think we can admit that they must save most of the twenty percent of it normally used for brain function - they're still losing a significant amount of power in your flabby carcasses!
If you still believe that there isn't more to it then just "humans supply the power" after reading those two quotes then this discussion ends here.
You still have yet to show and proof for your own statements that Zion and New Zion were built using thermal energy. (I ask for it because for the life of me I don't remember that ever being said or explained ever). As for Morpheus' quote it has nothing to do with the city becoming cramped and running out of room or supplies. He was commenting on that fact that Neo had created an increase of awakenings within the Matrix and that the Machines were becoming worried. Actually that quotes leans in my favor when used in its proper context because from the fifth attack of Zion up until now the city has held us all without any problems other then its defenses. That's counting the massive serge of awakenings done once the truce was implemented. Why this is so and where is my proof of it? Well look around Zion for starters and you don't see people overwhelmingly crowded while walking through its streets, in desperate need of food, and multiplying at an out of control rates. Three clear signs of over population. Second do some research on things such as methods of population control, birth and death rates, and such and they will show you exactly why the over population of Zion let alone both New Zion won't come till hundreds of years from now which is ample time to find a location and build another city.
If I am moving on to different topics I'm sorry but I have merely been replying in segments to topics you had already brought up.
