About a cubic yard of freshwater mixed with seawater provides almost two-thirds of a kilowatt-hour of energy. And scientists say a revolutionary new battery chemistry based on that theme could power edge data centers.\nThe idea is to harness power from\u00a0wastewater treatment plants located along coasts, which happen to be ideal locations for edge data centers and are heavy electricity users.\n\u201cPlaces where salty ocean water and freshwater mingle could provide a massive source of renewable power,\u201d\u00a0writes Rob Jordan in a Stanford University article.\n\nThe chemical process harnesses a mix of sodium and chloride ions. They\u2019re squirted from battery electrodes into a solution and cause current to flow. That initial infusion is then followed by seawater being exchanged with wastewater effluent. It reverses the current flow and creates the energy, the researchers explain.\n\u201cEnergy is recovered during both the freshwater and seawater flushes, with no upfront energy investment and no need for charging,\u201d the article says.\nIn other words, the battery is continually recharging and discharging with no added input\u2014such as electricity from the grid.\u00a0The Stanford researchers say the technology could be ideal for making coastal wastewater plants energy independent.\nCoastal edge data centers\nBut edge data centers, also taking up location on the coasts, could also benefit. Those data centers are already\u00a0exploring kinetic wave-energy to harvest power, as well as using seawater to cool data centers.\nI\u2019ve written about Ocean Energy\u2019s offshore, power platform using kinetic wave energy. That 125-feet-long, wave converter solution, not only uses ocean water for power generation, but its sea-environment implementation means the same body of water can be used for cooling, too.\n\u201cOcean cooling and ocean energy in the one device\u201d is a seductive solution, the head of that company said at the time.\nMicrosoft, too, has an underwater data center that proffers the same kinds of power benefits.\n\n\n \n\n\nLocating data centers on coasts or in the sea rather than inland doesn\u2019t just provide virtually free-of-cost, power and cooling advantages, plus the associated eco-emissions advantages. The coasts tend to be where the populous is, and locating data center operations near to where the actual calculations, data stores, and other activities need to take place fits neatly into low-latency edge computing, conceptually.\nOther advantages to placing a data center actually in the ocean, although close to land, include the fact that there\u2019s no rent in open waters. And in international waters, one could imagine regulatory advantages\u2014there isn\u2019t a country\u2019s official hovering around.\nHowever, by placing the installation on terra firma (as the seawater-saltwater mix power solution would be designed for) but close to water at a coast, one can use the necessary seawater and gain an advantage of ease of access to the real estate, connections, and so on.\nThe Stanford University engineers, in their seawater\/wastewater mix tests, flushed a battery prototype 180 times with wastewater from the Palo Alto Regional Water Quality Control Plant and seawater from nearby Half Moon Bay. The group says they obtained 97% \u201ccapturing [of] the salinity gradient energy,\u201d or the blue energy, as it\u2019s sometimes called.\n\u201cSurplus power production could even be diverted to nearby industrial operations,\u201d the article continues.\n\u201cTapping blue energy at the global scale: rivers running into the ocean\u201d is yet to be solved. \u201cBut it is a good starting point,\u201d says Stanford scholar Kristian Dubrawski in the article.