USA NATIONAL R&D INITIATIVES

WAVE ENERGY COMES OF AGE IN DESALINATION SOLUTION MIX

Earlier this year, the IDA reported on the success of its 2019 World Congress in Dubai, United Arab Emirates. As the premier global conference on advanced water-treatment solutions, this event focused on traditional methods of desalination and water reuse. However, IDA leadership made it clear that it is not resting on any traditional laurels brought on by past successes. Indeed, with the ambitious goal of establishing a new standard for the water industry, the IDA announced plans for several new initiatives and programs—including renewable-energy-driven desalination. Renewable energy technologies have been used for desalination, including solar power. However, solar power typically provides cheap electricity for desalination plants to operate; it is not used to directly desalinate seawater. Alternatively, wave energy uses mechanical energy to desalinate seawater. Once considered a pipe dream, wave-powered desalination could become a practical solution, especially during emergencies and for isolated coastal communities that must import clean, safe drinking water at great expense. As far back as 2014, a North Carolina-based start-up company, EcoH2O Innovations, proved that desalinating via wave-powered technology worked. The company’s Swell-Actuated Reverse-Osmosis System (SAROS) used highpressure pumps built on top of a round buoy to power the system with energy from the vertical motion of waves. These pumps took in water and sent it to a land-based unit that pushed the seawater into a pretreatment process to purge it of viruses, bacteria, salt, and sand before sending the water through the reverse-osmosis process. While a viable system, SAROS has not yet been brought to market. Wave-powered reverse-osmosis desalination systems like SAROS face a variety of challenges. The reverse-osmosis water purification process uses a partially permeable membrane to remove ions, unwanted molecules, and larger particles from water. These membranes, however, work best under constant conditions. “Reverse-osmosis membranes can’t currently handle the shocks resulting from wave motion or changes in water quality,” said Tzahi Cath, Professor of Environmental Engineering at the Colorado School of Mines. “The ability of these systems to deliver drinking water of consistent quality depends on consistent operating conditions, adequate pretreatment, and support systems that balance and smooth the operation of the entire system.” As far back as 2014, a North Carolina-based start-up company, EcoH2O Innovations, proved that desalinating via wave-powered technology worked.

To help improve the tolerance of reverseosmosis membrane technology, Cath’s research team has been working with the National Renewable Energy Laboratory (NREL) and the National Alliance for Water Innovation. “Membrane technologies that can better absorb the changes in pressure and water quality would go a long way toward making wave-powered desalination technology viable,” he said. Another challenge to wave-powered desalination is cost. Engineers and scientists worldwide—including those in Australia, China, Portugal, Scotland, and the United States—have been working for decades with governments and industry to research cost-effective ways to harness wave energy. Now the desalination industry stands to benefit from their findings. turned its focus to wave-powered desalination. Its Waves to Water Prize, launched in 2019, invites competitors to develop wave-powered desalination systems that can be deployed in disaster-relief scenarios and in remote coastal locations to provide potable drinking water. NREL, which is managing the Waves to Water Prize for DOE, at the end of 2019 awarded 20 teams from the CONCEPT stage with seed funding to develop detailed plans and models of their concepts as the competition moves into the DESIGN stage. “International organizations can become members of U.S.-based teams, sponsor their entries, or provide technical support—to name just a few examples—in this competition,” said Scott Jenne, NREL principal investigator for the Waves to Water Prize. From IDA’s perspective, wave-powered desalination presents a unique opportunity to address forward-looking initiatives of sustainability, renewable-driven desalination, and decreased impact on the environment. From IDA’s perspective, wave-powered desalination presents a unique opportunity to address forward-looking initiatives of sustainability.

As testament to the technology’s promise, the U.S. Department of Energy (DOE) recently As part of the mix of desalination solutions, wave-powered desalination is coming of age.