Analysis of a Wave-Powered, Reverse-Osmosis System and its Economic Availability in the United States

Abstract

A wave energy converter (WEC) system has the potential to convert the wave energy resource directly into the high-pressure flow that is needed by the desalination system to permeate saltwater through the reverse-osmosis membrane to generate clean water. In this study, a wave-to-water numerical model was developed to investigate the potential use of a wave-powered desalination system (WPDS) for water production in the United States. The model was developed by coupling a time-domain radiation-and-diffraction-method-based numerical tool (WEC-Sim) for predicting the hydrodynamic performance of WECs with a solution-diffusion model that was used to simulate the reverse-osmosis process. To evaluate the feasibility of the WPDS, the wave-to-water numerical model was applied to simulate a desalination system that used an oscillating surge WEC device to pump seawater through the system. The annual water production was estimated based on the wave resource at a reference site on the coast of northern California to investigate the potential cost of water in that area, where the cost of water and electricity is high compared to other regions. In the scenario evaluated, for a 100-unit utility-scale array, the estimated levelized cost of energy for these WECs is about 3–6 times the U.S.’s current, unsubsidized electricity rates. However, with clean water as an end product and by directly producing pressurized water with WECs, rather than electricity as an intermediary, it is presently only 12% greater than typical water cost in California. This study suggests that a WEC array that produces water may be a viable, near-term solution to the nation’s water supply, and the niche application of the WPDS may also provide developers with new opportunities to further develop technologies that benefit both the electric and drinking water markets.

Numerical Modeling and Dynamic Analysis of a Wave-Powered Reverse-Osmosis System

“…Yu and Jenne [12] presented a preliminary study on the potential levelized cost of water (LCOW) for California, which showed a similar LCOW as compared to the value estimation for the United Kingdom provided by Folley et al [7]. In the study, the WEC and hydraulic interaction was simulated using a wave-to-water numerical model.…”

Limits on the Range and Rate of Change in Power Take-Off Load in Ocean Wave Energy Conversion: A Study Using Model Predictive Control

“…There are two primary applications of wave energy converters (WECs) under consideration: converting wave energy to electrical energy and using wave energy to power the desalination of seawater. It has been argued that the application of wave energy to desalination, specifically reverse osmosis (RO) desalination, can be more economical than the production of electrical power [1] and several groups have worked to evaluate and advance the technology for that purpose [2][3][4][5]. The cited advantage of applying wave energy to reverse osmosis comes with the use of a hydraulic power take-off (PTO) with filtered seawater as the working fluid and direct coupling to the RO process; the advantage is that significant power conversion losses are avoided [3,[5][6][7].…”

“…Historical data for the occurrence rate of sea conditions near Humboldt Bay, CA, shown in Figure 2, are used to weight average power capture performance across sea conditions, providing estimates for annual average performance. These data were originally generated for [1] using the methods given in [28]. Bench-marking performance results of this study is facilitated by literature that has considered this WEC in design studies [1,3,7] and experimental testing [29], including results assuming the same rates of occurrence for sea conditions [1].…”

“…These data were originally generated for [1] using the methods given in [28]. Bench-marking performance results of this study is facilitated by literature that has considered this WEC in design studies [1,3,7] and experimental testing [29], including results assuming the same rates of occurrence for sea conditions [1].…”

Water Resource Management and Sustainability: A Case Study in Faafu Atoll in the Republic of Maldives

“…Mainly, studies are based on the use of wind turbines or solar plants, but there are also proposals where other renewable sources, such as sea currents, are used [34]. This application could be interesting particularly for some islands where the scarcity of drinking water is more severe.…”