Guwahati, Dec 30
Indian Institute of Technology Guwahati (IIT-G) on Monday said its researchers have developed materials that can produce energy from water, on a small scale.

These new ways of producing energy can be employed in household environments to support the concept of decentralisation of energy sources.

The researchers employed the nanoscale phenomenon called 'Electrokinetic streaming potential' to harvest energy from flowing water on the small length scale like water flowing through household water taps.

Similarly, the 'Contrasting Interfacial Activities' different types of semiconducting materials were employed to generate power from stagnant water, according to the study published in ACS Applied Nanomaterials.

The impending energy crisis that has arisen from the dual problems of dwindling fossil fuel reserves and environmental issues associated with the use of such fuel, has led to considerable research in alternative energy sources such as light, heat, wind, ocean waves, etc.

The generation of energy from water in various forms - river flow, ocean tides, stagnant water, and even raindrops, is now known as 'blue energy'.

While hydroelectric power from rivers is the traditional form of blue energy, there have been efforts to harness the power of water in other ways in recent years.

"When fluids stream through tiny channels that are charged, they can generate an electrical voltage, which may be harnessed through miniaturised generators", said study researcher Dr. Kalyan Raidongia, Department of Chemistry, IIT Guwahati.

Although the exploration of such electrokinetic phenomena and their possible use for energy conversion have been known for more than half a century, they have not been harnessed because of low efficiency arising from the unsuitability of channels for the fluid stream.

The humble efficiency of electrokinetic streaming potential based energy generating devices is attributed to the trade-off between high flow-rate and nanofluidic confinement.

The researchers demonstrated that power output can be improved by thousand times by attaining the best out of these parameters through biconical nanofluidic channels that interconnect tetrahedral and octahedral voids in the close-packed silica spheres.

Enhancement in the power density can be brought about through control of multiple parameters such as the diameter of the close-packed spheres, number of the spheres, the contact area of the electrodes, and pH of the streaming water, and the team is currently involved in such optimization efforts.

In order to extract power from stagnant water, devices were fabricated by employing doped graphene flakes, the Institute said in a statement.

The complementary charge transfer activities of doped graphene flakes based devices generate power just upon dipping in any kind of water source, like lake, river or seawater.

IIT-G develops materials to generate power from water