Oil briefly went negative a few years ago. If you decided to build a storage business dependent on negative oil prices for profit, you might just be coming online around now, and very much poorer than you were before. (Of course you would in fact have stopped a long time ago.)
There is good news though. With electric car sales slowing down (at least in the west) there is a surplus of batteries on the market, which makes grid storage projects more affordable. The incentives are currently pushing us towards decarbonizing our electric infrastructure faster and that is wonderful. As long as the politicians don't do anything dumb like slap huge tariffs on solar cells or something we should be making some real progress towards a green future.
But they do. Often literally.
Negative prices usually happen because of laws requiring minimum utilization, or subsides, or because they are so small and rare that it is not worth having someone on place to turn the switch.