Necessarily renewable because it is the cheapest possible energy long-term; you only need to pay for upkeep, not for resources to convert. Maybe this depends on whether you think renewables will become cheaper than coal/gas, and maybe you're pessimistic about that. I'm not.
Robust because the phenomenon can begin detached from the energy grid by profit-seeking entities with capital to invest. Doesn't need permission, can be smaller, independent and eventually have something to offer back to the grid, but don't require it initially. Ability to bootstrap outside of regulation as a result. More nodes, more competition, shared excess. Fewer singular points of failure, more redundant, less fragile.
"Future," because that's a great vision for the future.
What has even higher potential to be cheap is nuclear energy - when you don't care as much about (operation, storage) safety, a lot of costs fall out ...
Nuclear energy has high fixed costs but then scales pretty well. As crypto currencies with PoW become a major industry, it's not difficult to imagine it might be cost-effective to build huge nuclear plants in some corrupt African country. (Africa has also huge untapped uranium ore deposits)
Cost of capital is higher in less stable countries though - the backers need insurance against unexpected outcomes either way, corrupt African countries (or some future equivalent) would require less community buy-in but what makes that true would cause other worries to the owners of capital.
Nuclear works in stable, rules-following countries like France where its high energy paybacks subsidise good salaries for an army of bureaucrats enforcing the rules.
Nuclear can and will work with far fewer rules and fix cost once you next generation reactors with totally different operational safety requirements.
We are literally stuck with 50 year old technology in nuclear energy, as unfortunately progress has been slow.
With the fuel cost being basically free (thorium), the and the operational cost low because the system runs with little human intervention energy should actually end up incredibly cheap once we engineer these system in a better way.
