“…However, grid-connected datacenters can also provide ancillary services to the grid [191,192,193], i.e., they can absorb or supply power on short notice and participate in frequency regulation or reserves, for example. Such behavior can be obtained either by modulating the IT load [194] or using local storage resources, e.g., from existing UPSs or from supplementary storage units [195]. This can generate an additional stream of revenue for datacenter operators [196], as such services can be sold on markets or through long term bilateral contracts.…”