One theme I constantly see from writers who are excited to write about a Utopian Solarpunk future, is... "HOW DO I CREATE CONFLICT IN A UTOPIAN WORLD?" It's easier than you think because conflict is through character. If you start off by creating a solid character then conflict will automatically grow. Secondly just because you have a Solarpunk or Utopian world doesn't mean there are no conflicts. If you have no conflicts you have no story, no matter if it's Solarpunk, Cyberpunk, Utopian or Dyst
I really liked these story hooks also, more focused on community tensions : https://alxd.org/22-solarpunk-communities-and-story-hooks.html