When talking about sustainable energy (fundamentally solar and wind), the "problem" of the lack of continuity in the generation of these energies is often commented on, since the sun does not always shine and the wind does not always blow. And that is true, but it is a manageable problem.
The energy system has the particularity that the same energy that is consumed must be produced at each moment, since the energy that circulates through the cables cannot be stored. This is a serious limitation and that is why the energy networks have many systems to incorporate or eliminate energy generating units from the electrical network, depending on the demand of consumption. And it has always been that way.
With the new sustainable energy, it is known when more or less energy is going to be produced. At noon on a sunny day is when more electricity is generated by the solar panels, and when the wind blows, more electrical energy is available from wind sources. And today weather forecasts are known quite accurately all over the world.
What needs to be done, as has always been done, is to manage power generation with actual demand. And that real demand is first estimated (historical data from recent years is available) and then measured to adjust generation to that demand.
Solar and wind energy are cheaper every day, and there are experts who say that it would be appropriate to have a certain overcapacity to generate these energies, to adapt the amount of energy that is put into the network.
Here is a very interesting video about it: https://youtu.be/gIrm4uQHjUM
All the world's electrical networks have a certain excess generation capacity, to support possible peaks in demand that may occur.
A certain overcapacity for sustainable energy generation would give greater flexibility to the electricity grid so that it remains sustainable with certain increases in demand, making it possible to withstand certain peaks in demand without having to resort to fossil fuels.
If there has to be something in excess, let it be good (sustainable energy). I think that is the way to go.
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