A spare capacity status of each of multiple computing systems in a data center is monitored. Temporary workloads are assigned to these computing systems if there exists sufficient additional electrical power supply and capacity on power distribution lines. Thus, computing systems that are typically not productively used, such as those that are about to be decommissioned, have not yet been assigned for normal servicing, are reserved for special circumstances, or that are assigned to services that are currently in low demand, are temporarily used for productive data center purposes.