"Surplus" capture/use is a bigger problem than most people realize, not just for solar, but throughout the entire energy economy.
There's a reason you still see so many flare-offs in the petroleum industries, even though it's always been "burning dollars" and is now usually discouraged via imposed regulatory costs. Yet it still makes economic sense in many situations.
Why would people invest capital in capture technology that only gets used a fraction of the time? Whether it be at a solar plant, or a refinary, people will choose to invest that capital where it's use can be maximized. There are certainly situations where it makes sense economically, but many where it doesn't, and more situations where the capital can be better spent elsewhere.
Similarly, if a hypothetical town gets 15kw solar power during the day, and 15kw of hydro or wind during night, and needs 20kw backup/surge capacity from gas/nuclear/other, you've designed a system that requires a surplus of capacity, not just in generation, but also in transmission and distribution. In that context, surplus==inefficiencies.
This can be somewhat minimized by so-called smart-grid technology, but people tend to focus on technical capabilities and not what makes economical sense, which is much more limiting than people realize.