Apparently it's all the rage:
The name refers to solar power.
A 2014 manifesto tells us:
Solarpunk is about finding ways to make life more wonderful for us right now, and more importantly for the generations that follow us – i.e., extending human life at the species level, rather than individually. Our future must involve repurposing and creating new things from what we already have (instead of 20th century “destroy it all and build something completely different” modernism). Our futurism is not nihilistic like cyberpunk and it avoids steampunk’s potentially quasi-reactionary tendencies: it is about ingenuity, generativity, independence, and community.
And yes, there’s a -punk there, and not just because it’s become a trendy suffix. There’s an oppositional quality to solarpunk, but it’s an opposition that begins with infrastructure as a form of resistance.
It even has a Wikipedia page! (I guess they didn't have to wait as long as we did getting an entry about dieselpunk approved.)
I like the gist of this, although I'm not sure this has much to do with cyberpunk, steampunk and dieselpunk anymore? I remember the long and divisive debates we had about the "punk" in "steampunk" - I would be careful about using that term.
Although here it might actually fit.
What do you think? Something that will catch on?