There is something called base load that is currently established by power sources like coal, natural gas,oil and nuclear, these sources are continuous and are available on demand.

Currently Wind and solar are everything on top of the base load.

What Fusion does is ,it replaces the Fission nuclear and other base loads like coal, natural gas and oil.

While solar and wind energy will continue to increase no matter what.

Energy provided by Wind and solar is higher than Nuclear energy in 2021., so renewables are going to keep adding up, and once fusion comes it will clean up the grid by relacing dirty coal, natural gas and oil.