Ocean Wave Energy-Driven Desalination Systems for Off-grid Coastal Communities in Developing Countries

Abstract

Resolute Marine Energy, Inc. (RME) is based in Boston, MA and is developing ocean wave energy converters (WECs) to benefit remote off-grid communities in developing nations. Our two WEC technologies are based on the heaving and surging motion of a buoy on the ocean surface (the 3-D WEC) and on a bottom-mounted hinged paddle that oscillates in the full water column (the Surge WEC). Our computer models and wave tank tests have revealed conversion efficiencies as high as 31% in random sea states for the 3-D WEC and 40% for the Surge WEC. Our objective is to complete all the testing and prototyping of both WECs by the end of 2012. RME plans to use the Surge WEC in conjunction with a reverse osmosis seawater desalination system in order to provide fresh water to coastal communities in developing countries. The proposed system will operate completely off-grid and will represent a clean and low-cost solution to the water scarcity problem commonly faced by remote communities. The fresh water production process comprises three stages: energy extraction from waves, process water acquisition and pressure regulation, and reverse osmosis. We estimate that an array of about 25 Surge WECs can produce 0.9 million m3 of fresh water per year, which is enough to meet the water needs of about 30,000 people while eliminating about 104 thousand tons of carbon dioxide emissions per year. RME has identified a municipality in South Africa as its launch customer and has the support of the South African Department of Water Affairs to develop the project. In South Africa, 1.97 million people live on the coast where wave energy is abundant and each person needs an additional 700 m3 of water per person per year to comply with United Nations Millennium Development Goals. After the first deployment, RME will expand to other remote communities in South Africa.