This shows pretty well that we need two kinds of storage. One relativly high efficent, but more expensive for 9% of use cases. The other one large, low cost to built, but larger losses are possible. So I would say pumped hydro, batteries and similar storage in the first category, while biomass and hydrogen are good canidates for the second one.
However priotrity should be to go towards the reaching the 99%. That is a really good position for the rest and well 61% of global electricity still comes from fossil fuels.