1. A computer implemented method of managing energy usage, said method comprising: accessing, by an energy management policy accessor that comprises one or more processors, an energy management policy that specifies an overall maximum energy usage permitted in total for a plurality of devices located at a first structure; accessing, by an energy usage rule accessor that comprises the one or more processors, an energy usage rule for a single device of the plurality of devices, the energy usage rule pertaining specifically to said single device and indicating a maximum energy usage for said single device; receiving, by an energy usage rule comparator that comprises the one or more processors, an energy usage measurement of said single device and firstly comparing, said energy usage rule with said energy usage measurement; secondly comparing, by the one or more processors, said energy usage and said energy management policy; and based on said first and second comparing, generating, by the one or more processors, at least one instruction to modify an energy usage profile of said single device to correlate with the energy usage rule associated with said single device and said energy management policy, the energy usage profile controlling an amount of energy used by said device, thereby enabling efficient energy management.