The term 'punk' has a specific meaning, but for some genres is used inappropriately. There's not really any 'punk' in steampunk or dieselpunk, but the term is appropriate for cyber and solarpunk, which are both ideas of how an individual can rebel against the control of a state or authoritative machine by using its own technology against them.

Cyberpunk assumes the world continues down the road of consolidation and hypercapitalism, where as Solarpunk is hopeful that we can rebel against the cyberpunk future, and that individual change can bring about a future worth living in.

Solarpunk could almost be described as Techno-Anarchism, embracing technology (especially green tech) to liberate the individual and the world.