Besides this general fact, there are additional benefits for the Bitcoin network: Fluctuations in renewables (i.e., long vs. short phases of wind or sun, rainy seasons) with an inflexible demand profile (i.e., day-night-cycle) lead to excess energy such that utilities companies have to burn electricity to not overload electricity networks. Excess electricity that is not needed by the grid and that cannot be stored needs to be grounded and wasted. This is the cheapest form of electricity for the Bitcoin network.
This is the reason why it is likely that renewable energy providers will become themselves miners to use efficiently excess renewable energy in the low consumption phases. It is just a natural addition to their business model.