This paper presents IoT and big data infrastructures for demand response services for household participation in smart grid. The innovative aspect of this infrastructure is in the application of IoT and distributed systems to simplify the demand response workload. With this in mind, the goal is to design an effective infrastructure that enables streaming of energy consumption data from smart plugs and real-time analytics of that data. Real-time analytics should provide knowledge on electricity consumption that would enable household appliances to be automatically turned on or off, in order to contribute to the stability of the electricity grid without disturbing consumers��� comfort. As a proof of concept, data from ENERTALK open dataset were analyzed using Apache Spark. Results show that the proposed infrastructure can be used for the analysis of consumption data in order to gain insight into the consumption patterns.