Monterey Bay Aquarium Research Institute

The MARS Ocean Observatory Testbed

Benthic Microbial Fuel Cell

Generating electricity from seafloor microbes
Lowering a Benthic Microbial Fuel Cell into the water
Lowering the Benthic Microbial Fuel Cell (BMFC) into the water for a test deployment. Image: Oregon State University

[Text adapted from Oregon State University web article] A benthic microbial fuel cell converts chemical energy from seafloor microbes into electrical current. Microorganisms play two key roles in the system: 1) they create an electrochemical redox potential within the sediment, and 2) they facilitate the transfer of electrons from donors to the circuit.

As microbes in seafloor sediment consume the organic matter, they use up oxygen and create anoxic conditions in the sediment. There is a voltage difference between the anoxic sediment and the overlying oxygen-rich sea water—it is that voltage difference that the fuel cell exploits. Because the fuel cell can extract electricity from chemical energy without using moving parts, it has the potential to provide a sustained source of energy in the deep sea.

The objective of these fuel cell experiments is to generate a steady supply of power that could eventually be used to operate remote oceanographic instruments, such as water-quality sensors. These devices are usually powered by batteries. Fuel cells could provide a continuous power supply, so that deployment time of the instrument would not be limited by battery life.

Last updated: Jul. 25, 2012