  Currently, one of the hottest topics in the Internet of Things (IoT) research
domain regards the issue to overcome the heterogeneity of proprietary
technologies and systems so as to enable the integration of applications and
devices developed for different environments in a single interoperable
framework. Towards this objective, virtualization is widely used to foster
integration and creation of new services and applications. Similar benefits are
expected by its application in the smart grid arena. The use of a
virtualization middleware is expected to enrich the capabilities and
opportunities related to the use of smart grid devices. In this paper, we
propose key features for an interoperable, re-usable, elastic and secure smart
grid architecture which is cloud-based and relies on REST APIs. To highlight
the benefits, a practical case study is presented, where outlined
functionalities are implemented in a cloud-based IoT platform. The advantages
brought by the proposed middleware in terms of interoperability, re-usability,
privacy and elasticity of the underlying infrastructure are discussed.
