Decentralized desalination of brackish water using an electrodialysis system directly powered by wind energy

• Published in: Desalination Vol. 377; pp. 54 - 64
• Main Authors: Malek, P., Ortiz, J.M., Schulte-Herbrüggen, H.M.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2016
• Subjects: Brackish; Desalination; Drinking water; Electrodialysis; Energy consumption; Fluctuation; Oscillations; Power fluctuation; Renewable energy; Sustainable water provision; Turbulence intensity; Wind; Wind energy; Wind speed; Wind; Power fluctuation; Renewable energy; Desalination; Sustainable water provision; Electrodialysis
• ISSN: 0011-9164; 1873-4464; 1873-4464
• DOI: 10.1016/j.desal.2015.08.023

A novel directly coupled wind–electrodialysis system (wind–ED) with no energy storage was developed. The aim was to perform laboratory experiments, investigating the impact of wind speed (2–10m/s), turbulence intensities (0–0.6 TI), and periods of oscillation (0–180s) on desalination performance and energy consumption. The system produced good quality drinking water (<600mg/L NaCl) over the range of parameters tested. Water production and energy consumption increased with wind speed, until both parameters levelled off at wind speeds above the rated value of the wind turbine (vrated: 7.9–8.4m/s). The impact of wind speed fluctuations on system performance was insignificant up to a TI of 0.4 (i.e., moderate fluctuations). The water production declined under high turbulence intensity fluctuations (TIs≥0.5) and long periods of oscillation (>40s). The main challenge in direct coupling of ED to wind energy was not the magnitude of fluctuations but the impact of power cycling off during long periods of oscillation and lengthy periods of no wind. Interestingly, the specific energy consumption of the process remained relatively unaffected by the fluctuations, suggesting the system to be an electrically robust and reliable off-grid desalination technique for remote water stressed locations.
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•Electrodialysis was, for first time, directly coupled with wind-energy.•Desalination rate was a function of the wind speed and ED stack resistance (Rstack).•Increased Rstack=higher rotor momentum and reduced sensitivity to fluctuations•Extreme wind fluctuations (TI≥0.4, oscillation≥40s) decreased water production.•Robust performance and unchanged SEC despite extreme wind fluctuations