Simplifying wildly: Electricity producers sell their electricity at auction. They all offer a bid (x Wh at price y), the utility accepts bids from lowest to highest until demand is filled, and then everybody gets paid the highest accepted price to fill demand. Wind and solar pretty much always bid their forecasted capacity at $0, because they have no additional costs between producing and getting curtailed.

So the silk incinerator only gets to sell electricity if demand is extremely high and the utility needs to accept even the highest bid.

Batteries would fix a lot of this, but western nations have extremely long interconnection queues (project waiting to be allowed to be connected to the grid), mostly because of stupid bureaucratic reasons.