Wave Energy System Advances for Seawater DesalinationS. Himmelstein | July 11, 2017
A wave-action device conceptualized to pump cold seawater to the surface to dampen the intensity of hurricanes, and then re-imagined as a promoter of phytoplankton growth and climate change mitigation failed to find commercial success. The latest iteration is a pump that uses wave power to send pressurized seawater onshore for desalination.
Developer Atmocean Inc. and partner Reytek Corp., both based in New Mexico, have collaborated with Sandia National Laboratories to advance the technology. Product testing and component manufacturing progress has been realized through the New Mexico Small Business Assistance program, a public-private partnership among Sandia Labs, Los Alamos National Laboratory and the state of New Mexico.
Full-size seawater pumps have been built and tested off the coast of Oregon in 2011 and off Peru for six months in 2015.
Atmocean is now working with Sandia Labs on computational modeling of the wave energy system to improve the pump design. Following trials in a test tank at the Texas A&M University Haynes Laboratory, the system will be deployed later in the year off the coast of Newfoundland, Canada, for additional testing that will demonstrate the prototype in an operational environment.
The 200-foot by 200-foot array of pumps floats on the ocean. As waves pass, the buoy ingests sea water, and as the buoy settles, it pumps seawater through hydraulic lines back to shore where it enters a zero-electricity desalination process.
Water arrives onshore at about 180 psi, where energy recovery devices are used to boost 14% of the incoming seawater to 900 psi, the pressure needed to run reverse osmosis. The system runs 24/7 and production depends on wave action. Under typical ocean conditions in southern Peru, 50 million cubic feet of pressurized water is pushed to shore in a year. Fourteen percent of that is desalinated, producing 5 million cubic feet of fresh water annually that can be used for agriculture or consumption.