Water scarcity is an imminent threat, with projections indicating that the next few decades will see a significant increase in the struggle for clean water. Factors contributing to this crisis include extreme weather, the depletion of aquifers, saltwater intrusion, and growing urban populations. Addressing this challenge may be critical not only for drinking water but also for food production, manufacturing, and energy generation. However, a radical new desalination technology, which proposes to place desalination plants on the ocean floor, is emerging as a potential solution to slake the world’s growing thirst.
Historically, desalination has been the lifeline for regions like the Caribbean and the Emirates. Traditionally, desalination has been a method of last resort, primarily due to its high cost. Tom Pankratz, a veteran in the desalination industry, has noted that “desalination is the most expensive way to make water” but points out that advancements in technology have made it a more feasible option compared to the past.
In the earlier days of desalination, methods involved boiling seawater to create steam, which could then generate electricity. This energy-intensive process was so extreme that some even proposed using nuclear power to support it. Currently, the largest desalination plant, located in Ras al-Khair, Saudi Arabia, utilizes evaporation to produce a significant portion of its water.
A breakthrough occurred around the turn of the millennium with the advent of reverse osmosis technology. This process forces water through a plastic membrane, filtering out salt and impurities while requiring approximately half the energy of traditional methods. Countries like Trinidad and Israel have adopted this approach, and the result has been the establishment of numerous desalination plants worldwide. Nevertheless, costs remain high, with estimates ranging from $2 to $6 per 1,000 gallons, mainly driven by fluctuating electricity prices.
Despite the benefits of deploying desalination plants along coastlines, there are significant challenges. Marine life can be adversely affected by water intake processes and the concentrated brine returned to the ocean can pose risks to aquatic ecosystems. Such concerns led to California’s rejection of a long-planned desalination project in Huntington Beach in 2022.
The innovative idea of submersible desalination facilities is gaining traction, thanks to companies like Flocean, Waterise, and OceanWell. These organizations propose to install desalination plants at a depth of at least 400 meters. The primary advantage of this approach is the ability to harness the ocean’s natural pressure instead of expending energy to bring seawater to land and then pressurizing it. This method can yield an energy savings of up to 40%, making the process more efficient.
There are additional advantages to this sub-sea approach. These underwater facilities can be placed away from the shore, eliminating competition for beachfront property and allowing for scalability without the need for extensive negotiations over land use. Furthermore, the brine output, being released at significant depths, is quickly dispersed and poses less harm to marine ecosystems compared to surface-level operations. The deeper water is also less contaminated by pollutants, allowing for greater membrane longevity.
While the technology shows promise, the current state of these unfathomable desalination plants is primarily in the pilot stage. Flocean and Waterise have established modest facilities in Norway, while OceanWell has set up a demonstration plant in California. These projects aim to prove the reliability of their systems in securing multi-decade contracts with government customers. Such contracts are essential to transform these promising demonstration technologies into operational businesses.
Flocean’s operations begin with a pilot facility positioned just offshore of Norway, producing ultrapure water for a local ice manufacturer. Meanwhile, OceanWell’s facility at the Las Virgenes Municipal Water District is another testament to this innovative approach.
The first full-scale deep-sea desalination plant is anticipated to come online in 2026 at the Mongstad industrial facility in Norway, with a goal of producing around 264,000 gallons of water daily from a single unit. Additionally, Waterise plans to construct a plant in the Gulf of Aqaba to produce between 7.9 million and 13 million gallons of water per day.
Despite these advancements, uncertainty remains about the long-term feasibility and operational challenges these submerged systems may face, such as maintenance requirements and adaptability to changes in salinity and temperature. Historical precedents remind us that while many innovative ideas have been proposed, not all have succeeded. Pankratz, however, believes that at least one of these companies will find success in operating successfully underwater.
In conclusion, as global water scarcity looms ever closer, the potential of submerged desalination technologies presents a new frontier in the quest for clean water. By tapping into the ocean’s vast reserves and leveraging natural pressures, we may finally have a viable solution to one of humanity’s most pressing challenges. As we look forward to the success of these innovations, the hope remains that they might be able to turn the tide in our battle against water scarcity.
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