Bringing together multiple desalination technologies
Water Duck. Canvasback Desalination System. B&V SurfBuoy. These are just a handful of start-ups that have each received $47,000 to bring wave-powered desalination technologies to life.
In total, a pot $800,000 pot has been made available by the U.S. Department of Energy (DOE) and the National Renewable Energy Laboratory (NREL) as part of the Waves to Water Prize.
Launched in early 2019, the ongoing competition challenges innovators to produce potable drinking water through wave energy-powered desalination systems.
The awarded companies and solutions varied in scope and scale, coupling together multiple desalination technologies, including membranes and pumps, in novel ways.
One solution from B&V called the SurfBuoy involves an inflatable buoy attached to a piston pump with pulley, to provide pressurised water to a reverse osmosis membrane (RO) unit.
Meanwhile, Water Duck includes a "slack moored, simple and robust wave-driven pump with proven marine onboard RO desalination".
A collaboration between Hawaiian, Indian and Swedish companies called Nalu e Wai (Waves Into Water) involves an oscillating “wave surge converter” tailored to disaster response, capable of achieving total dissolved solids under 300 mg/L.
Current challenges facing wave-powered desalination
Aside from the start-ups in the Waves to Water Prize, multiple efforts continue globally to commercialise and scale wave-powered desalination.
Wave2O, a process developed by Boston-based Resolute Marine Energy, recently made the finals of MIT’s Solve Challenge.
This solution uses a series of paddles that are moved backwards and forwards by the waves, with the resulting energy harnessed to filter seawater.
Meanwhile, Australian company Carnegie has faced multiple challenges scaling up its CETO technology, which harnesses ocean energy from the movement of submerged buoys.
The failure of microgrid subsidiary Energy Made Clean left the company lacking funds to complete a project off the coast of Garden Island.
The next stages in the competition
For the NREL prize, competitors will return to the lab for the fourth stage, CREATE, which will launch in February 2021 and run through September 2021.
In this stage, contestants will build a functional prototype or proof-of-concept of their system and develop a plan to build and deliver their technology for testing at Jennette’s Pier during the final DRINK stage, scheduled for spring 2022.
The desalination systems must be capable of providing clean water in disaster and recovery scenarios, as well as in water-scarce coastal and island locations.
"These competitors and their wave-powered desalination systems could hold the key to coastal community resilience," said Daniel R Simmons, assistant secretary for energy efficiency and renewable energy at the department of energy.
“Their ground-breaking ideas could help us find a sustainable solution to the challenge of water scarcity, in both the wake of disasters and for day-to-day needs in these communities.”
