  Installing smart meters to publish real-time electricity rates has been
controversial while it might lead to privacy concerns. Dispatched rates include
fine-grained data on aggregate electricity consumption in a zone and could
potentially be used to infer a household's pattern of energy use or its
occupancy. In this paper, we propose Blowfish privacy to protect the occupancy
state of the houses connected to a smart grid. First, we introduce a Markov
model of the relationship between electricity rate and electricity consumption.
Next, we develop an algorithm that perturbs electricity rates before publishing
them to ensure users' privacy. Last, the proposed algorithm is tested on data
inspired by household occupancy models and its performance is compared to an
alternative solution.
