Energy issues are like a castaway dying of thirst while floating in a vast ocean. Similarly, energy is everywhere, but releasing, capturing and transporting it is a whole other story. Along with fusion reactors, blue energy is one of the most attractive and elusive power sources yet to be harnessed.that is electricity generated by the osmotic process, based on the tendency of two liquids with different densities to reach an equilibrium state by exchanging particles. One of the most common uses of osmosis technology today is water purification.
Large amounts of water have flowed under the bridge since Professor Pattle first theorized in the 1950s that differences in the composition of salt water from the sea and fresh water from rivers flowing into the sea could cause osmotic fluctuations. I came. According to theory, if both liquids are separated by a special semi-permeable membrane, freshwater will naturally flow towards the saltwater chamber, reducing the salinity of the latter. As the volume of this second chamber remains constant, the pressure of the brine increases, allowing it to drive the power generating turbine. The energy released by such means cannot be ignored. In fact, studies show that it could cover up to 80% of the world’s energy consumption. However, the moment of discovery did not go much further, as there was no technology to harness that enormous power source. The practical side of things had not yet been addressed.
By 1973 there had been new advances. Inspired by the salinity difference between the Dead Sea and the Jordan River that flows into it, American professor Sidney Loeb devised a membrane system based on pressure-delayed osmosis. The PRO system uses a specially developed membrane to implement the principle proposed by Professor Pattle. However, the cost of manufacturing such membranes remains prohibitive and has remained so for years. It was in 2009, he said, that a power plant with such technology was opened in Norway. However, the amount of power generated was only 10Kw, barely reaching 1w/m, so it was not a breakthrough.2Additionally, bacterial activity clogged the membrane openings, further reducing efficiency. The project ended in 2013. It’s time to try other complementary technologies.
It was the very same Professor Loeb who developed the alternative. After four years of his research on PRO technology, he is ready to present Reverse Electrodialysis technology (RED). This time, instead of using the pressure of water, the approach was to use the positive and negative charges that exist in salt water and fresh water separated by a membrane as an electric current. In this system, it is the salt ions that pass through the membrane, one side allowing only positive ions to flow to the cathode and the other side to pass negative ions flowing to the anode. This creates a charge that can be used. His first RED-based power plant was opened in 2014 with the support of the Dutch water research institute Wetsus in Leeuwarden, Netherlands. Since then, the resulting company, his REDstack, has been working on power generation with an output of 50 KW.
Nanotechnology to the rescue
However, recent advances may unlock the full potential of this osmotic energy. The key is to reduce the size of the openings in the membrane to the atomic scale. Thus, in late 2016, the journal Nature announced the development of his three-atom-thick film of molybdenum disulfide capable of producing up to 1 MW/m.2In other words, its surface could power 50,000 energy efficient light bulbs. In addition to low production costs, these membranes do not require power plants and can be installed directly at the mouth of a river to generate electricity. As with other nanotechnology advances, the current challenge lies in producing consistent, uniform films on an industrial scale.
Source: Nature, All About Circuits, BBC
