This has been happening in the US for the past 10 years. The big switch has been away from coal and some slower natural gas generators towards more nimble natural gas generators. Coal and other natural gas generators take a while to start up and shut down (think on the order of a day), which don't work well for coordinating with renewables and are much more expensive to operate. So companies have been switching to faster natural gas generators that start up in minutes to hours to support when demand is higher.