The ubiquity of sensors has offered great opportunities to monitoring infrastructures to track the real-time state of observed environments. Monitoring systems rely on synchronous massive data to calculate the environment state. However, collecting and communicating massive data usually leads to expensive energy consumption due to high sampling frequency and communication cost for the sensors operation. Clamp-on wireless sensors are a flexible plug-and-play technology easy to deploy where sensors operate on integrated batteries. This paper introduces a highly accurate time synchronization protocol to coordinate the operation of individual clamp-on sensors deployed as an energyconstrained monitoring solution. While maintaining sensors highly synchronized, the proposed protocol reduces drastically data communication and energy consumption of the sensor network. To minimize the energy consumption further, we optimize the protocol behavior using a genetic algorithm. The protocol has been modeled in VDM for formal analysis, implemented and compared to a state of the art protocol.