Saltwater Electricity: Scientists Created a More Powerful Source of Blue Energy
Scientists have created what could possibly be the most powerful osmotic power generator in the world.
A team of international scientists from the United States and Switzerland developed a powerful osmosis power plant that is capable of greater power generation than any osmotic power generator that came before.
"Making use of the osmotic pressure difference between freshwater and seawater is an attractive, renewable and clean way to generate power and is known as 'blue energy,'" the researchers wrote in the study published in the journal Nature.
For their version of blue energy, the research team filled a small tank with water separated into two compartments, which are connected via an electrode. One part contains high concentration of ions, while the other has lower concentration. The membrane separating the water, which is only three-atoms thick, has a single opening - called the "nanopore" - through which only positive ions could pass. When a positive ion squeezes through the nanopore, an electron transfers through the electrode, producing electricity.
According to the researchers, the thinness of the membrane and the radius of the nanopore were crucial to the generator's success, as larger membranes with a number of openings could generate bigger amounts of energy. The researchers said that a membrane the size of one square meter (10.7 square feet) could produce one megawatt (MW) of electricity, which could power about 50,000 energy-saving light bulbs, Market Watch reports.
Osmosis is the process by which solvent molecules move through a semi-permeable membrane from one part of the water that has lower solute concentration into another part with higher solute concentration to equalize the concentrations in both ends of the membrane.
As water molecules pass through the membrane, the difference in solute concentrations in the water will cause molecules from the "fresh water" side to pass rapidly to the seawater side, increasing the pressure on the seawater side. The pressure turns the turbines of a generator and produces electricity.
However, earlier prototypes of osmotic power plants have generated insufficient power and were uneconomical. But this new osmotic power plant is estimated to be capable of producing around 2 terawatts (TW) of energy, which is about the output of 2,000 nuclear reactors.
Moreover, the technology could generate great amounts of electricity all year long and could be placed in river estuaries where seawater and fresh water meet.