Delivering ancillary services with data centres

Ancillary services are the mechanisms power grids use to address short-term variability in supply and demand as well as the impact of power plant or transmission line failures. Organizations providing such services can earn revenue or at least reduce their energy costs. This paper explores options for large data centres to reduce costs in this way. Simulation results are presented for a system that models the processing of a workload and the resulting energy use, focusing on the impact of providing specific types of ancillary services. Trace data recording the workload from three supercomputing facilities along with pricing information from a US-based electrical grid are used. Results presented show energy costs reduced by up to 12% with only a small impact on the quality of service provided to users of the data centre. Further reductions in energy costs are shown for data centres willing to cede more control over short-term energy consumption. The potential of ancillary services markets are compared against following-the-renewables approaches, using wind farm data to argue why providing ancillary services may be more effective than optimizing operations based on the production of local renewables.

► Ancillary services address short-term variability and failures in power grids.
► Data centres may provide ancillary services more effectively than power plants.
► Compensation for providing ancillary services may reduce data centre energy costs.
► Simulation results show up to 12% cost savings for responding to grid failures.
► Cost savings >12% may result if willing to cede more control to the grid operator.