The several features of smart metering:

There is an overview [2013-Zekeriya Erkin].

In [2014-Jing Zhao] , the battery with capacity C is connected to the original house hold electricity network, and charging or discharging it (whose maximum rates are both $\beta$) adds noises (i.e., the battery energy b(t)) to the real load of the appliances d(t), which constitutes the smart meter’s reading s(t) = b(t)+d(t), and the c(t) is the energy stored at the battery at time t.

In order to achieve non-trusted center, the methods based on multipaty secure computatio are proposed. [2011-Gergely Acs] and [2014-Fabienne Eigner] proposes three methods based on secure multiparties computation.

Reference

[2013-Zekeriya Erkin] Privacy-Preserving Data Aggregation in Smart Metering Systems

[2014-Jing Zhao] Achieving Differential Privacy of Data Disclosure in the Smart Grid

[2014-Fabienne Eigner] Differentially Private Data Aggregation with Optimal Utility

[2011-Gergely Acs] I have a DREAM! (DIffeRentially PrivatE smart Metering)