You just need to move the excess to times of high demand.
> Most of the solar production will go wasted.
Germany saw renewable curtailments (including wind) of 3.5% in 2024. I can only find reports it will reach 10% by 2030 in Germany and 10% in the EU. I would define "Most" as 50%+.
> That means that the price of the solar production will tank and go negative during most of the spring-summer period. And that is terrible as far as ROI on the production systems are concerned.
This depends on the market. The UK guarantees a price for renewables that have a Contract for Difference (CfD), so they're unaffected. I don't know much about the other European markets, so this might happen.
Any developer will account for this though, so money will flow out of renewables and into storage if there are serious issues around over capacity - unless you have schemes like the UK's CfD.
Finally, I disagree with your prediction
> we might doom the ROI of an entire industry for the decades to come
You have plenty of price signals in energy markets so I can't see a scenario where there's a complete misallocation of resources into renewablews and not storage. In addition investment predictions for renewables and storage are healthy and not of an industry in distress.
It is still nowhere enough. It is barely the capacity to support few hours of consumption of the European grid.
Most of the solar production will go wasted.
That means that the price of the solar production will tank and go negative during most of the spring-summer period.
And that is terrible as far as ROI on the production systems are concerned.