It's not sustainable to use renewable exclusively, at our current rates. But over time things will shift, battery storage technology will play a big part in the future in stabilising energy production. As well as better efficiencies in renewable.

Although the biggest thing will be more people shifting to more efficient energy use cases. The irony considering that we are in a bitcoin forum, that cryptocurrency is actually such a big waste of energy. The price of a bitcoin, can be somewhat tied to the difficulty in acquiring (i.e. the energy cost).