The technology developed by the consortium of the Politecnico di Torino, the Italian Institute of Technology and Smart Manufacturing Lab will increase the operating persistence of AUVs (Autonomous Underwater Vehicles) by obtaining electricity directly from seawater.
A first phase of tests and evaluations was successfully completed at the Naval Support and Experimentation Centre (CSSN) in La Spezia, with the laying of a network of miniaturized Microbial Fuel Cells (MFCs): bio-electrochemical systems developed by Italian researchers (Politecnico di Torino, IIT, SMLab) in collaboration with the US research centre SPAWAR (Space and Naval Warfare Systems Command), thanks to a memorandum of understanding signed with SEGREDIFESA, capable of generating electricity by exploiting the metabolism of aquatic micro-organisms.
To date, most AUVs are powered by rechargeable lithium-ion or lithium-polymer batteries, nickel-metal hydride batteries or aluminium-based fuel cells, which may require substantial maintenance and costly refills, and produce dangerous waste that must be managed with special care. MFCs generate electricity by directly converting the chemical energy of the organic substrates naturally present in seawater. Taking advantage of seawater's "nutritional" properties, they can potentially act as a perpetual source of electrical energy, enabling long electrical autonomy.
Objectives and testing
The MFC network installed at the CSSN is under continuous instrumental control to assess the performance obtained. The ultimate goal is to define the potential of this technology and to demonstrate its use both in fixed monitoring stations and on diving AUVs. This latter application — of greatest interest to the CSSN — would improve vehicle operating conditions by making possible the autonomous generation of electricity to power low-consumption operating sensors.
The trials, conducted by the consortium of researchers from the Politecnico di Torino – Department of Applied Science and Technology, the Italian Institute of Technology – Turin, and Smart Manufacturing Lab, fall within the National Military Research Plan (PNRM) under the name MUES — Microbial fuel cells as power Enablers for Underwater Sensors. The activity was carried out in collaboration with CSSN staff and falls within the "Endurance AUV & Persistence" research line of the joint CSSN-ISME "Sealab" laboratory for the study and experimentation of innovative autonomous vehicles.