• "constrained off" by the network operator, basically meaning that the wires near the project are at maximum capacity and can't take more, or
when a project switches off it is simply responding to the market signal.
this @OpenNEM chart from SA last week shows almost daily -ve pricing events.

so while a project might have weak earnings during spring, they could easily make it up during summer.
don't forget that there are other factors:
• pumped hydro and batteries elsewhere
• old generators leaving market
• changes in demand
• hydrogen production
• metals processing
• desalination
• hydro pumping
• battery charging
• water pre-heating & pre-chilling.
negative prices are, by design, a signal to the market. watch it respond!
/end