The main idea is to integrate Energy Harvesting devices in a small size buoy, each having the capability to harvest energy from different sources (light, wind, mechanical vibrations, temperature differences, etc.). These different energy sources are used to power sensors in order to collect data from the environment and to transmit them via a radio connection (like LoRa) with a central unit, powered by renewable sources (solar or wind), which provides sufficient power for a preliminary data analysis and the transmission over a long distance. The sensor nodes will be powered by commercial photovoltaic (PV) cells, a device developed by UNIGE able to capture energy from the wind (FLEHAP) and a recently developed device acted by the waves motion (WEHPLET), obtaining a cumulative power of the order of tens of mW with a global volume of a few hundred cm³. These units will also be suitable to be integrated with flexible PEH and TE devices for producing sustainable electric energy by efficiently exploiting mechanical energy sources from environmental and solar energy, respectively, thus enabling a more effective energy harvesting.Actually, a first model of the buoy is under study  both through numerical simulations and in the water tunnel hosted at the DICCA-UNIGE department in order to optimize its shape and mechanical properties (position of the gravity center, position of the center of buoyancy).