top of page
Lanon Wee

Wave-Powered Floating Desalination Machines

"Given the harsh environment of the sea," affirms Susan Hunt, "our technology has been engineered to endure such conditions - able to withstand the ups and downs of the waves throughout the day and night." Ms Hunt serves as the chief innovation officer for Oneka Technologies, a Canadian start-up that specializes in constructing floating desalination systems which convert seawater into potable water. Although the output from large desalination plants near shore require a lot of energy to be rid of salt, Oneka's small units are able to function off of energy generated solely by the ocean waves. Ms Hunt states that traditionally, desalination facilities are run on fossil fuels, yet the world is now at a turning point, seeking to move away from these types of operations. Over three hundred million individuals globally have come to count on desalinated water, based on the International Desalination Association, an international trade organization. This water is provided by upwards of twenty-one thousand facilities, nearly double the amount which existed ten years previously. It is probable that the need for this type of vegetation will increase as the world population increases and global warming keeps stressing fresh water supplies. At least half of the people on the planet exist in areas experiencing intense water shortages over a period of at least a month annually, as indicated in a report from earlier in 2020. Additionally, research from the same year asserted that the desalination industry will increase by 9% annually until 2030. Membrane-based desalination works by allowing water to pass through a semi-permeable membrane, as the salt molecules are too large to pass through, while filtered water passes through. Currently, two methods for desalination of seawater exist: thermal and membrane. Thermal desalination utilizes a heating process that causes water to evaporate and leave the salt behind, although this practice tends to be quite energy-intensive. Membrane desalination, on the other hand, allows only the filtered water molecules to pass through a semi-permeable barrier by blocking the larger salt molecules. The process of reverse osmosis, also known as membrane-based system, utilizes saltwater as it is pushed through a semi-permeable membrane that acts to block out the salt. Though energy is still required for this to take place, it is less than what is needed for thermal techniques. In both scenarios, the energy supply tends to not come from renewable sources or nuclear, thus resulting in higher carbon dioxide emissions. The use of these techniques can cause an output of salty water or brine that is densely concentrated. If this salty water is not diluted before being put back into the ocean, “dead zones” - locations where the salt concentration is too high for marine life to survive - can be formed. Floating desalination machines, which are buoys tied to the ocean floor, make use of a membrane system that is merely powered by the waves' actions. The buoys utilize the energy from the waves in order to convert it into mechanical pumping forces. This action results in drawing seawater in and expelling a quarter of it into a desalination system. Furthermore, the generated fresh drinking water is then sent to land via a pipeline powered only by the passing waves. Ms Hunt states that the technology is operated completely without electric power, it is entirely powered by mechanics. The units only need waves that are one metre in height to operate, and the organization desires to begin selling them commercially in the coming year. There are three sizes available, the biggest of which is 8m long and 5m wide, and it has the ability to produce up to 49,000 litres (13,000 US gallons) of drinking water every day. The buoys draw in three quarters of seawater which is then recombined with the brine that is generated. After it is combined, the resulting mixture is released back to the ocean. Ms Hunt commented, "It has merely 25% more saltiness than the original sea water, which is a much lower degree of salinity than typical desalination techniques." Oneka's system is said to be modular, being able to have multiple buoys anchored near one another, and also friendly towards marine life. In the Netherlands, Desolenator, a Dutch company, has a peculiar way to power desalination with renewable energy - solar panels. The thermal evaporation system is powered by the heat and electricity gathered, with any electricity not used immediately being put in batteries and any unused heat stored in hot water tanks, providing a continual energy supply so desalination can continue running night and day. Desolenator does not expel any brine into the ocean; it retains all of the salt for commercial applications. Lauren Beck, the firm's head of projects, pointed out that brine has been a nuisance for us in desalination for a long time. She described brine as an unwanted by-product, and said that we convert it into profitable salt by crystallizing it. Since we do not use any hazardous chemicals, the salt produced is of superior quality and can be used for various industrial purposes. Emphasis is placed on the model of a circular economy. This series, New Tech Economy, examines the effects of technological advances on the forming economic world. Louise Bleach, Vice President of Business Development at Desolenator, remarks that the global lack of fresh water is causing it to become more valuable. She states, "People are referring to water as if it were the subsequent oil." Chedly Tizauoi, an expert in the field of water supply and treatment systems who is currently a professor of chemical engineering at Swansea University, emphasizes the importance of reducing water consumption before exploring desalination systems powered by sustainable energy. "He recommends using less water and only when necessary due to the energy and chemicals used for pumping and treating it respectively," he says.

Comments


bottom of page