A research brewing at Michigan Technological University could one day make underwater battery replacement far less necessary, as scientists develop a system that generates power by harvesting organic matter from the ocean itself.
Led by biological sciences professor Amy Marcarelli, the BioLogical Undersea Energy (BLUE) program is exploring ways to extend the endurance of submerged sensor systems using energy drawn directly from seawater.
At the center of the effort is a microbial fuel cell (MFC) designed to capture electricity naturally produced by microbes as they consume nutrients in the water.
The system uses granulated activated carbon (GAC) to trap organic material from moving seawater while also giving microbes a surface to grow on.
As microbial layers build on the GAC, they create low-oxygen zones that allow electricity generation even in oxygen-rich ocean environments, a condition that normally limits microbial fuel cell performance.
“When oxygen is around, that’s what microbes use to accept electrons during cellular respiration, because they get the most energy from the process that way,” Marcarelli said.
“We’re trying to build [an MFC] that will work in an environment that isn’t very conducive to the operation of microbial fuel cells.”
Reducing the Naval Logistics Burden
Maintaining underwater sensor networks is both costly and operationally demanding, often requiring support vessels, dive teams, or retrieval missions to replace depleted batteries.
Researchers believe fleets equipped with MFC-powered systems could significantly reduce those requirements by continuously generating energy while submerged.
The system could also support more covert operations, as fully submerged sensor platforms are harder to detect, track, or disable.
“There are increasing deployments of all kinds of sensors in the marine environment for observing ecological conditions, organism migrations, and acoustics relevant to naval defense,” Marcarelli stated.
Sending the System to Action
The research team first tested the concept in 2025, with the MFC producing electricity for the projected 30-day period.
Following the trial, researchers developed four updated battery units and deployed them during a short submersion test in Galveston.
Three of the units successfully generated power, while a fourth behaved differently, giving the team additional insight into how operational conditions could influence system performance.
Researchers are now preparing a larger 10-unit deployment expected to last a month, with the collected data helping shape a possible year-long mission in the future.
“What we’re really doing on our end is combining remote sensing assets, field data, experimental lab data, and then actual MFC deployment experiments,” said Michael Sayers, research co-principal investigator.
