The challenge that isn't covered here is that the grandeur of Singapore is far far easier to achieve with authoritarian centralization than the anarchic style of solarpunk. And people are compelled by the grandeur of a large expensive project in different ways than the DIY scale.
So how can a ragtag group in SF or Berlin make something that captures imagination just as well as Singapore?
By transforming public projects in that direction. Berlin wants to expand its U-Bahn system for example. That means a lot of new stations to be designed in a solarpunk style. It is even better then Singapores airport, which is naturally not that solarpunk.
I like this, I’ve been working on a story about a neighborhood of squatters who build a solarpunk style community in a crumbling suburban block. I think imagining how large projects can be built and managed without authoritarian control is the first step in making that a reality.