Ok after writing this, I realized that a block and tackle pulley system might work: https://en.wikipedia.org/wiki/File:Pulley3a.svg https://en.wikipedia.org/wi

Ok after writing this, I realized that a block and tackle pulley system might work: https://en.wikipedia.org/wiki/File:Pulley3a.svg https://en.wikipedia.org/wiki/File:Pulley3a.svg A 200 m (600 ft) diameter, 4 million m3 float, generating 1 MW, would have a tension of 4 billion kg. That would need 533000 pulleys with 1 cm2 steel cable at 7500 kg tensile strength. So 266000 pulleys on each end, which is a 2D array of about 512 pulleys on a side. This doesn't actually seem that difficult to build on an industrial scale. The cable would travel about 2100 km a day, at 25 m/sec (about 55 mph). The cable would have a total volume of 2100000/10000 = 210 m3, or 6 m on side (20 ft), with the ends connected to the opposite sides of the pulley system. So that's quite a spool at the generator. It should be slightly mobile, either on wheels or a spring so that it can adjust to rogue waves. Also it should probably be made from a polymer that's resistant to seawater instead of steel. Unfortunately we'd need 1000 of these plants to make 1 GW. Just goes to show how mindbogglingly much power humanity uses. Maybe we could at least try to conserve haha.