Solarpunk is, by definition, an optimistic future. The greenery and solar panels are trappings, not the heart of the story itself. Solarpunk opposes cyberpunk, positing that humans will learn and use technology to better themselves, society, and the world, living in peaceful coexistence rather than oppressive darkness. I'm not saying your story was bad, far from it. It reminded me of some of the old pulp sci-fi I read and enjoyed as a kid. But it wasn't solarpunk.