Decentralized is not really the problem here: it's more about the links between each installation and the surplus. It's harder to see it with electricity, but think as if it was water for example: if people were pumping water at home and pushing it into pipes to others, and not that many water was actually needed, where would it go?
By decentralization I mean something different, decentralization of energy production. The fact that, say, a village can decide to install a solar panel array to satisfy some of their energy demands, and they don't have to rely on powerful (and often global) energy companies who mine coal or process oil, is an important game changer in terms of power relations between people.
You just have to buy the solar panels from a global megacorp instead.
Don't get me wrong, this kind of decentralisation can be very effective in small isolated communities such as the Scottish islands, but for most places doing it locally is both more difficult and more expensive.
