I can't get this idea out of my head. I keep thinking it will work but there must be something wrong... Do me a favor a tell me why it won't work so I can stop thinking about it! In it's simplest form there's no crazy math to understand just a few basic laws of physics and mechanics. I guess I'll start at the beginning. I was watching the Discovery channel a long time ago and saw a commercial about deep ocean exploration. There was a clip of a probe near the bottom of the ocean that imploded due to the intense pressure. The idea was born. I knew there must be a way to harness this intense pressure that covers our planet. Now, imagine a probe that is the exact shape of a capsule, like one that you would swallow containing medicine. Internally, the capsule has a vacuum. Imagine dropping this capsule into the water but it being heavy enough to sink to the bottom of the ocean. The pressure would gradually compress the capsule the deeper it sunk. At one point the forces compressing the capsule would be very, very strong. Well, that's good but there needs to be a way to expand it again and that can be simply done using springs. Very, very strong springs. As the capsule resurfaces (getting to that part still) the springs store some of the energy given to them during the compression and release it. So, the capsule needs to find its way from an area of low pressure then to high pressure and repeat. There is a special gear train I saw in an old mechanical design book a long time ago that can help. The gear train transforms two way horizontal movement (like that of the capsule compressing and expanding) to one way rotational movement (like that of a propeller on a boat). So, where I'm going with all this is that a propeller would be attached to the capsule so it can move now. At the same time some gearing to speed up the movement of the propeller would need to put inside this capsule too. While we're at it a generator can be stuck in there with it's own gearing. So, if you pointed this capsule nose first into the ocean and dropped it it would eventually compress and propel itself faster towards the bottom of the ocean while generating some electricity and storing some energy in the springs. But there's still the problem of the capsule moving from an area of low pressure to an area of high pressure and back again. Simply chaining multiple capsules together in a circular or elliptical pattern (each nose pointed in the same direction) would solve this. They would work in tandem helping to push one another with a great amount of force from an area of low pressure to high pressure and back again. It would happen fairly easily too because the chain would be balanced (mass) at all points. An interesting thing to point out too is that the system will orient itself properly by itself because the capsules at the top of the system will be expanded displacing more water than the contracted capsules at the bottom. Finally, no one wants to put a machine in the ocean unless they have to. This really doesn't have to be. I guess a very deep hole could be dug and filled with water or whatever (mercury) and then just drop the chained up capsules into it. It could be in a desert or outer space... it doesn't really matter.