PPU: Privacy-Aware Purchasing Unit for Residential Customers in Smart Electric Grids

Retail energy markets where residential customers with storage devices can purchase energy ahead of time are beneficial to both customers and energy suppliers. The customers can maximize their utility by making strategic purchase decisions while suppliers can leverage on the early purchase decisions to develop a better cost-effective plan to serve the demands. A crucial observation is that the flexibility of storing energy in a battery separates the time of purchase and time of use for the stored energy. This can be exploited to address a rising privacy concern amongst the smart grid users which is maintaining the confidentiality of the consumption profile of the customers. In this paper, we propose an embedded unit that implements an energy purchase strategy which integrates ahead of time purchases with the privacy concern of the customers in a cost effective fashion. The embedded unit called PPU supports a quantifiable trade-off between the privacy and the utility enjoyed by the residential customers. Simulations results characterizing the performance of the proposed PPU are included in the paper. We outline an 'ideal' attack and show that PPU can still provide a privacy guarantee of 90%.