I was working on a side project to design an alien fleet that is wandering in the universe, and harvesting energy from planets for their needs. While I can think of ways to make that happen (geothermal, coal/fossil, "alien technology"), I was actually wondering if it is possible for people on earth to do similar things.
Specifically, I wonder if it is possible for people on earth, with modern technology (21st century), to utilize the kinetic energy from earth by decelerating the rotation?
Utilize here not just mean to help with launching rockets, but more referring to a machine/mechanism that can decelerate the planet rotation, and gain electricity/thermal energy from this process.
If it is not feasible right now, what would be a plan to make that happen, if the technology level is not a hard constrain? Lower technological level is more preferred.