These are called ancillary services. There are 3 levels: frequency control (for example dams), primary reverse (fast acting power, in less than 10s), and second

These are called ancillary services. There are 3 levels: frequency control (for example dams), primary reverse (fast acting power, in less than 10s), and secondary reserve (slow acting: < 15min). Participants can either be positive (they consume more energy, for example PHES systems), or negative (they inject or consume less energy). All these ancillary services are paid (annual auction + per case). Nowadays, it's getting bigger with VPP: virtual power plants, which aggregate small loads (i.e. small ~1MW generators) in order to propose a bigger load to TSOs. It's all automatic If you're interested: https://www.swissgrid.ch/en/home/customers/ancillary-services.html https://www.swissgrid.ch/en/home/customers/ancillary-service...