it is overconsumption. for one, it would be much easier to need our needs with renewable energy sources if we just consumed less energy and weren't so wasteful with it. more to the point, energy is only one part of the problem. all the clean, free energy in the universe doesn't stop deforestation, overfishing, and other habitat loss and environmental damage from unsustainable agriculture as a result of overconsumption. solving the emissions issue doesn't count for much if all the ecosystems we rely on collapse and we starve to death anyway.
degrowth is the only thing that could work at all, the lack of compatible economic and political models that would be compatible with is exactly my point, which is why we will ultimately not solve the problem.