Having worked in a handful of factories, including in very energy intense sectors (aluminum and semiconductors), I'd say that's not the norm. Smelters are a not

Having worked in a handful of factories, including in very energy intense sectors (aluminum and semiconductors), I'd say that's not the norm. Smelters are a notable exception, as they can be turned down/off relatively quickly as long as the metal in process doesn't solidify - in which case the line will be down for months and will be very expensive to fix and startup again. I could see it being more common on commodity products or when the order book is light. Energy pricing varies by region, but is sometimes based on consumption during the grids' highest couple consumption days in the last year. In those cases, curtailing production can have a huge impact on total cost for the next year. It's a bit of a guessing game, but there is an industry around energy consulting for factories and forecasting which days will be the highest consumption (typically the hottest days).