Typically the most expensive part of the energy is regulation, so if you don't need to connect to the grid (like you are just powering a factory nearby), don't need to worry about emission (nobody lives near you), and have no need to worry about harming the land (like you are building your stuff on a colony / occupied land your population in ruling will not live in, like Bikini Atoll), then you will have the cheapest energy.
I can see in the near future someone would wage war against another country and then instead of sending human to occupy it, send in drones and war machines remotely controlled, then build a power plant using the conquered energy source, and build a data center to power productivity at the expense of an occupied land. Since human lives are no longer involved they will be really reckless and the result very uneven.