Muddying the current supply

A fuel cell that draws on the electron-rich environment at the bottom of the sea has been developed in the US.

Microbes lying undisturbed in ocean mud produce electrons as a byproduct of the digestion of organisms such as phytoplankton. These accumulate in chemicals in the surrounding sediment.

The prototype device, developed at the US Naval Research Laboratory in Washington DC and Oregon State University, generates a current when one electrode is placed on the seabed and one in the water above.

The prototype produces 10 milliwatts of electricity, but the researchers plan to scale up the device to generate around one watt, allowing the cell to be used to power oceanographic instruments.

The ocean floor has the potential to be a huge source of energy, although developing methods to effectively tap in to such a diffuse source remains a challenge, the researchers said.