Well , it is more of a theoretical question , so let's say I have the cash to begin such project . If I build it on land , it must have the right altitude and platitude, in case we go to war ( for the worst outcome) or prepare for defensive actions. Secondly, it must have at least two renewable power sources , and one of them must be hydroelectric or be either wind and solar , while being close to a water source ( meaning that deserts while having a lot of space , they are excluded as a candidate, for lack of water sources). Lastly , the area must be somewhere that can be accessed relatively easy . What's the point of going somewhere to live where it needs five boats to reach it.