I doubt the electric companies would allow those users to use the companys power grid independently; and it would have to be nearly impossible to set up your own physical power grid (both financially and getting the rights to build on the roadside).
Right now In Europe , at least in northern EU, it is allowed to give your energy back to the gird and get paid for it.
But there is bureaucracy and also the price what they give is smaller than price which we pay when we buy from them ( at least that was some time back when i was researching this problem). Its possible to sell power to the grid here in the US, and I can imagine its possible in most all countries; but that doesnt make it a decentralized grid, it just makes you one of the power companys freelance suppliers.
In order to implant one of these systems youd need your own physical grid uncontrolled by any power company, which is probably the biggest roadblock of any plans to build a decentralized power grid.