Low-overhead power trace obfuscation for smart meter privacy

Smart meters communicate to the utility provider fine-grain information about a user's energy consumption, which could be used to infer the user's habits and pose thus a critical privacy risk. State-of-the-art solutions try to obfuscate the readings of a meter either by using a large re-chargeable battery to filter the trace or by adding random noise to alter it. Both solutions, however, have significant drawbacks: large batteries are prohibitively expensive, whereas digitally added noise implies that the user entrusts the utility provider to protect his/her privacy.This work proposes a hybrid approach in which zero-average noise is inserted in the power trace by means of a small energy storage device (battery or supercapacitor); the distinguishing feature of our approach is that this obfuscating device is indistinguishable from any other load and therefore it complicates by construction the load disaggregation task performed by the provider or by a malicious third party. Simulation results show that our device can achieve comparable or superior privacy enhancement as that of a solution based on a large battery and therefore with smaller cost.