Electricity from stagnant, flowing water
doi:10.1038/nindia.2020.4 Published online 13 January 2020
Researchers from the Indian Institute of Technology in Guwahati have invented graphene- and silica-based devices that can generate electricity from stagnant and flowing water.
These devices, they say, could potentially be used to make electricity from water stored in a bucket and water flowing from taps in household set-ups.
Besides emitting greenhouse gases, fossil fuel reserves are fast depleting, pushing researchers to look for alternative sources of energy.
To meet this challenge, the scientists, led by Kalyan Raidongia, designed a tiny generator using modified graphene flakes coated on filter papers1. They then tested its efficiency in extracting power from stagnant water collected from various sources such as lakes, rivers and seas.
They found that it was possible to generate power just by dipping the graphene-based device in these water sources. When dipped in various samples of stagnant water, it produced a voltage of up to 570 millivolts. It was stable and retained its power-generating efficiency for a few days.
Next, the researchers designed a device using close-packed silica spheres with tiny channels2. The silica-sphere-based device generated power from steaming water. It is possible to enhance its power-generating efficiency by changing the diameter and number of the silica spheres, and the pH of streaming water.
Although the devices generate small voltages, they are a step closer to the development of safe and reliable alternative power sources that can eventually reduce the load on a centralised grid, the researchers say.
1. Deka, J. Electrical power generation from the contrasting interfacial activities of boron- and nitrogen-doped reduced graphene oxide membranes. ACS. Appl. Nano. Mater. (2019) doi: 10.1021/acsanm.9b02049
2. Saha, K. et al. Energy from the nanofluidic transport of water through nanochannels between packed silica spheres. ACS. Appl. Nano. Mater. 2, 5850-5856 (2019)