People have been looking at ways to desalinate seawater to provide drinking water for centuries. Particularly in arid areas of the world, governments and private companies have explored a plethora of technologies to convert salt water into fresh water, using the abundant ocean to provide safe drinking water in areas facing severe freshwater shortages. However, this has been extremely costly and impractical in the past. But now, a Norwegian firm thinks it has created a new way to convert water, using the power of waves.
The main reason that companies avoid desalination operations is due to the high energy cost. It requires around ten times more energy than any other water source, as well as producing a significant amount of carbon emissions. Therefore, large-scale desalination projects require their own power plants to keep them running.
Desalination operations traditionally relied on boiling seawater to get rid of the salt. However, in recent decades more countries have been using reserve osmosis techniques, relying on high pressure to move salt water through a membrane and leave it trapped. This process requires less energy, although it is still far from low energy 4 kWh needed to produce just one cubic meter of drinking water. In addition to high energy usage, desalination has significant set-up costs, requiring expensive infrastructure and maintenance to run operations. For this reason, in areas where there are other water sources available, water conservation and reuse are more popular.
However, desalination has long been a popular technique in the Middle East, much of which is extremely arid making access to fresh water difficult. Saudi Arabia introduced two private distillation condensers in the city of Jeddah in the early 1900s, as the demand for drinking water grew. Later, the Saline Water Conversion Corporation (SWCC), an independent government organization, was established in 1974 to oversee desalination projects. And in the UAE, desalination operations provide around 42 percent of the country’s drinking water needs.
At present, many desalination operations are powered by fossil fuels, meaning they produce high levels of greenhouse gas emissions. And as populations across the Middle East increase and more desalination plants are built, there are concerns about their impact on climate change. However, plants can be powered by renewable energy sources, such as solar power, making them much cleaner. But it’s not all that simple. Laurent Lambert, Water-Energy-Climate Public Policy Assistant Professor at Doha Institute for Graduate Studies, explains that “The first fundamental issue with the plants is that most of the desalination infrastructure isn’t ready for solar energy. Secondly, solar panels must be cleaned often, so you need water. Cleaning these panels would add to existing water stress.”
Now, one Norwegian firm thinks it has the right method to provide greener desalination operations. Ocean Oasis has built a wave-powered prototype device that it hopes will deliver the blueprint for offshore floating desalination operations. The ten-meter-high plant, with a seven-meter diameter, was installed in Las Palmas in the Canary Islands to test its performance. Ocean Oasis believes its technology will allow for “the production of fresh water from ocean waters by harnessing the energy of the waves to carry out a desalination process and pump potable water to coastal users.”
Innovation Norway, Grieg Maritime Group, the Gran Canaria Economic Promotion Society, and other organizations provided funding for the project. The firm hopes that the project will provide a more affordable method of desalination to an area with abundant saltwater resources. Low rainfall, high soil permeability, and aquifer overexploitation have meant that the region is facing water scarcity, looking for alternative ways to provide fresh water. The new technique would reduce reliance on fossil fuels to power desalination operations.
Once tested, Ocean Oasis plans to build a second, scaled-up structure with the capacity required to produce water for consumption. There are high hopes for the project’s use of wave power as wave and tidal energy projects remain relatively few compared to other renewable energy sources. Governments are beginning to boost their funding for the research and development of ocean energy projects, but it is still largely untapped.
The Canary Islands is not the only area looking to develop innovative desalination methods, with the US Department of Energy (DoE) having held a competition with $3.3 million in prizes for the most innovative wave-powered desalination proposals. In the Waves to Water Prize, participants were asked to design, construct and test devices using wave energy to produce drinking water from salt water. Oneka Technologies was awarded the grand prize of $500,000 for its device Oneka Snowflake after a successful testing phase in North Carolina.
After years of trying to develop cost-effective desalination operations, the best large-scale projects we have to date remain extremely carbon-heavy. With support from state governments, new innovative projects are now being seen, with the potential to turn salt water into clean drinking water without detrimental effects on the environment. However, these projects remain in the early phases and will require significantly more funding to roll out on a wide scale.
By Felicity Bradstock for Oilprice.com
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