Effect of User Cooperation on Smart Meter Privacy With Rechargeable Batteries

In smart metering systems, a rechargeable battery can be utilized to protect the privacy of a user from the utility provider by partially masking the load profile of the user. In this line of research on using rechargeable batteries for privacy protection, most existing works have studied only single-user systems using rechargeable batteries. In this letter, we consider a multi-user scenario where the power supplies of two or more users are combined before sending them to the utility provider. We study the effect of such a user cooperation on enhancing the user privacy by deriving upper and lower bounds on the minimum leakage rate. Our simulation results show that the information leakage of each user can be reduced by a factor of the total number of cooperative users.

I. Introduction

Smart meters play a key role in electrical grid systems [1]. In such a system, smart meters deliver the load profile of a user to the utility provider in real time which enables the utility provider to manage the energy efficiently. However, the delivered profile may incur potential risk of privacy loss from each user's point of view [2]. It is known that an adversary with access to the load profile can infer private information of a user by using data mining algorithms [3]. One possible solution to mitigate such a privacy risk is to incorporate a rechargeable battery [4]. By charging and discharging the battery, it is possible to partially mask the load profile of a user. In this line of research, various battery charging policies to protect the user privacy have been studied mainly for single-user systems [5]–[8]. In particular, using the information-theoretic leakage as a privacy measure, the work [8] characterized the minimum leakage rate and proposed an optimal battery charging policy for a single-user system.