In some ways Solarpunk is the opposite of Cyberpunk.
If solarpunk is the sun, then cyberpunk is the moon (with a secret base built by a megacorporation)
If cyberpunk is dark, gritty streets in the slum, then solarpunk is bright rooftops (with plenty of community-owned solar cells and gardens)
In other ways, they're exactly the same.
Solarpunk is what happens when the cybrepunks win.
Cybrepunk is what happens when the solarpunks stop fighting.
Sunbeam City is a solarpunk instance.