Atmocean has a promising solution for the future of clean, affordable water and environmental sustainability. Among the many alternative energy sources available, Atmocean has settled on wave energy as a tool for converting ocean water into fresh water and opening up new coastal agriculture opportunities in countries around the world. For more information see the IDTechEx reports on Off Grid Zero-emission Electricity and Desalination.
Waves Roll In, Energy Rolls Out
The Atmocean system relies on capturing wave energy through an array pump system; however, instead of generating electrical energy through transformers pumping energy into the grid, the arrays pump seawater ashore. Arriving under pressure, it undergoes desalination by reverse osmosis, where salt and other solutes get forced out, leaving drinkable water behind, according to the Organization of American States. This ingenious system neatly sidesteps the energy hunger in traditional desalination systems that is a big deciding factor in operation and economy.
As waves pass under the array the buoys rise. A series of free-floating platforms called Variable Sea Anchors or "VSAs" are connected beneath the pump and provide drag to the rising buoys. The pumps located between the VSA and buoy are designed to take advantage of the resulting tension to pull in sea water and pump it towards shore. The entire array acts in series with five pumps along three separate strings to increase the volume and pressure of water being delivered on shore through a central pipe. The seawater is then run through an R/O system that takes advantage of the arriving pressure to desalinate the seawater with no external energy input. Pressurized seawater can also be directed to land based aquaculture. As Atmocean reaches economy of scale and realizes additional efficiency, future arrays could be used for power production with pressurized water going through a simple Pelton water wheel to generate renewable electricity.
Ocean Harvest on Land
Using ocean power to create fresh water could open up crop irrigation for many who have these alternative energy sources quite literally on their doorstep. The system — designed for easy implementation — uses a modular design that is straightforward to ship and uses local resources. Without needing an external energy supply or highly technical infrastructure, nations can tap this abundant local natural resource through what Atmocean describes as a Zero Electricity Reverse Osmosis desalination system. For the global community, especially in areas where water supplies are vanishing, this system could help make the world's coastal deserts green, said Atmocean.
Seawater In, Fish Out
Atmocean believes their technology will help revive areas where fishing has become sparse. "As marine fishing closures come into effect, fishery stakeholders may be forced to move away from their livelihood ... Atmocean arrays help restore the ocean ecosystem as they act as de facto Marine Protected Areas or MPAs. These artificial nurseries allow natural fishing stocks to recover, setting the area on course for future fishing opportunities."
Wave arrays introduce floating networks of pumps and anchors to habitats, which can have both negative and positive impacts. There is a risk of fouling, with larger ocean mammals getting tangled in mooring lines and equipment, according to Oregon State University. However, the university also suggests that with careful planning, wave energy arrays could also be a boon for smaller creatures. As artificial reefs, they could provide sheltered no-go zones to colonize and inhabit, where prey species could live and breed safely out of reach from predators.
Alternative Energy Sources
Since this type of marine renewable energy system has not been tested over long periods, the effect on the coastal environment is mostly unknown. However, as ocean fisheries decline, and opportunities for self-sufficiency disappear, wave energy that turns salty seawater into a tool for farming could be a game-changer for many nations currently struggling with food security.
In addition, not only could a zero-energy desalination system deliver crop irrigation for farming in areas where growing crops is a struggle, but the introduction of new operations such as fish farming could deliver sustainable and self-supporting agriculture to many coastal communities around the world.
There is also a possibility that as wave energy harvesting becomes more efficient, these coastal communities could also become the net energy exporters of the future, reversing dependent status and playing a greater role in the global market.
In the meantime, we need more innovators to keep pushing the boundaries of alternative energy so we can offer more solutions to problems that may ultimately affect us all.
Source: Northrop Grumman Corporation, Atmocean
Top image: Atmocean