We present the design of a Wireless Sensor and Metering Network (WSMN) with energy harvesting capability for long lasting monitoring power consumption of AC appliances. Energy harvesting makes the monitoring activity completely energy autonomous and the network can operate unattended eternally. The system consists of a network of measurement devices which is open to connect Smart Grid Management services and Energy Configuration and Optimization Tools in the Cloud. Each node integrates a WISPES W24TH module to provide perpetual analysis of energy measurement.