Smart Meters (SMs) measure and report energy consumption of individual users to the utility provider at short intervals on the order of minutes. While SM data is used to increase the efficiency in electricity distribution, it also conveys sensitive private data on the energy consumption behaviour of individual customers. In this paper, privacy in a smart metering system is studied from an information theoretic perspective in the presence of alternative energy sources and storage units. An alternative energy source provides increased privacy by diversifying the energy source, and the storage device filters the real energy consumption to reduce the leaked data. Connections between this problem and rate-distortion theory is established, and both theoretical and numerical results are presented.