IIT-Madras researchers working on power from estuaries

Chennai, Aug 16 (IANS) Researchers at the Indian Institute of Technology-Madras (IIT-M) are working on 'Osmotic Power' or power from estuaries, an alternative source of power, it was announced on Friday.

"Osmotic power generation is, as name suggests, based on the osmotic pressure that is generated when a semi-permeable membrane separates salt water from fresh water. This pressure can be converted into electricity," Vishal Nandigana, Assistant Professor, Fluid Sytems Laboratory, Department of Mechanical Engineering, was quoted as saying in a statement from IIT-M.

"The first osmotic powerplant was built in 2009 in Tofte, Norway, and produced 4 kilowatt of power, which, while sufficient to perhaps run a clothes dryer, is inefficient for any large scale use," the Institute said.

In 2016, a team at the University of Illinois, Urbana Champaign, found that membranes made of extremely thin layer of molybdenum di-sulphide were able to generate osmotic power of 1 MW per square metre.

Nandigana was also part of the University of Illinois team.

In a recent study published in the Nature Review Materials, Nandigana takes the research further and presents a detailed discussion of the membrane's potential with comparisons and pointers to go forward.

"Our molybdenum sulfide membrane produces higher power density than other membranes studied so far and is much better than its nearest competitor boron nitride nanotubes, which have been shown to produce power density of only 1 kW/m2," Nandigana said.

"The increase in power generation compared to earlier studies is because of the use of single atomic layer of molybdenum di-sulphide, which is ion-selective, and the osmotic pressure generated voltage is augmented by the ionic current produced," he added.

According to the statement, the IIT-M team is trying to first produce membranes in the scale of square centimetres rather than square micrometres that are currently possible, with future plans to increase size further.

This is based on the calculation that a single membrane, roughly one square meter wide, would generate enough power to light up 50,000 energy-saving light bulbs, IITM said.