Osmotic Generator In Development

Mini-generator uses salt water for power


Figure 1: Harvesting osmotic energy with MoS2 nanopores.—Nature Journal image

Start small, aim big—that’s the ideology behind many a project. For nanoscientists, the scale for this approach is exponentially more minuscule. This does not mean, however, that they aren’t cognizant of keeping the endgame in mind for their tiny discoveries to transition into bigger practicalities. Witness the atom-sized micro-generator concept recently detailed by scientists at the Swiss Federal Institute of Technology, which, if expanded to just a three square foot model, would conceivably produce a megawatt of electricity. If you like atomic jargon, here are the details

The generator’s main function involves the conversion of salt-to-freshwater and the process of osmosis. Aleksandra Radenovic, the nanoscientist who published the schematics for the mini-generator on July 13, headed the experiment using a membrane containing molybdenum disulfide (MoS2). This compound is used in a thin sheet with microscopic, electrically-charged holes and allows certain sized salts from the salt water source to permeate, while deflecting other kinds of salt away. The testing procedure utilized a box that had two compartments with different salt content. These two compartments in the box are connected by a sheet of the compound material. In this environment, the salts will naturally attempt to move toward equilibrium, forcing them to attempt to penetrate the pores in the sheet. As they do this, they generate a small amount of electricity due to the electrical charge within the salts themselves. This forms an electrical current through their movement.

The next step for these researchers is to expand the scale of the operation, or essentially make the ‘generator’ larger. At its current microscopic size (just a tiny sheet membrane of the material with a few even tinier holes) it wouldn’t produce a significant amount of energy to run electrical power. The development is significant because of its potential, if larger sheets of the material could be perfected. Radenovic’s team, for one, has a lofty goal of attempting to create sheets big enough to elicit a megawatt of power—a benchmark that would equal 50,000 LED lightbulbs.

This story was first reported by William Herkewitz of Popular Mechanics.

*Other news in the generator world: a recent report shows promise in generators with capabilities of meeting the EPA’s regulations for mercury reduction



  1. Nobels & Whistles | Electrical Apparatus Magazine - October 13, 2016

    […] “The molecular motor is at the same stage as the electric motor was in the 1830s, when scientists displayed various spinning cranks and wheels, unaware that they would lead to electric trains, washing machines, fans and food processors,” the academy said. “Molecular machines will most likely be used in the development of things such as new materials, sensors and energy storage systems.” […]

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