Well, I doubt it a bit how much pumped hydro capacity is there in Portugal, but you'd need an obscene capacity if you wanted to go full renewable partially based on solar panels. Found this by quick search:
"However, the dependency on electricity imports from Spain will increase significantly, especially in drier years. " https://www.sciencedirect.com/science/article/abs/pii/S2352152X24037800
Basically you'd be using Spain as energy source when you don't have enough energy at hand.
Hydro is more or less constant and wind is random. How does one cover a huge amount of solar energy when it's out? You can't increase hydro and you can't force wind to blow.