As solar, wind, and hydropower continue to grow, new research into sustainable technology might make these game changers old news. The EPFL’s Laboratory for Nanoscale Biology has found a way to use osmosis, or the naturally occurring phenomenon when saltwater comes into contact with freshwater through a membrane, into a renewable source of energy, and it is surprisingly powerful.
Researchers published their findings in Nature, detailing the construction of a power generation system that features a membrane only three atoms thick. This semipermeable membrane allows salt ions through to the other side, eventually creating an equilibrium in salt concentration – the very process of osmosis. What the scientists have done is found a way to harness the electrical charge from the salt ions, leading to impressive results.
The properties of the membrane only allow positively-charged ions through, leaving the negatively-charged ions where they are and creating an environment for voltage to build between the two cells. The transfer of ions establishes a current, which is helped along by the voltage in the system.
Made from molybdenum disulfide, the membrane can be made easily in a lab or found in nature, making the system easy to produce. The researchers estimate that 1MW of electricity, or enough to power 50,000 LED lightbulbs, can be generated by just a 1m² membrane with 30 percent of its surface covered by nanopores, or membrane holes. These systems could be installed in estuaries, where freshwater meets the sea. And, since water flows even when the sun does not shine or the wind does not blow, this renewable technology could generate energy around the clock.
Images via Steven Duensing