Special Issue Research Papers

Harvesting Natural Salinity Gradient Energy for Hydrogen Production Through Reverse Electrodialysis Power Generation

[+] Author and Article Information
Mohammadreza Nazemi

Department of Mechanical Engineering,
Georgia Institute of Technology,
Atlanta, GA 30332-0405
e-mail: mrnazemi@gatech.edu

Jiankai Zhang

Department of Mechanical Engineering,
Georgia Institute of Technology,
Atlanta, GA 30332-0405
e-mail: jzhang794@gatech.edu

Marta C. Hatzell

Department of Mechanical Engineering,
Georgia Institute of Technology,
Atlanta, GA 30332-0405
e-mail: marta.hatzell@me.gatech.edu

1Corresponding author.

Manuscript received November 17, 2016; final manuscript received January 15, 2017; published online May 2, 2017. Assoc. Editor: Dirk Henkensmeier.

J. Electrochem. En. Conv. Stor. 14(2), 020702 (May 02, 2017) (6 pages) Paper No: JEECS-16-1152; doi: 10.1115/1.4035835 History: Received November 17, 2016; Revised January 15, 2017

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. Here, we model a novel approach to convert this source of energy directly into hydrogen and electricity using reverse electrodialysis (RED). RED relies on converting ionic current to electric current using multiple membranes and redox-based electrodes. A thermodynamic model for RED is created to evaluate the electricity and hydrogen which can be extracted from natural mixing processes. With equal volume of high and low concentration solutions (1 L), the maximum energy extracted per volume of solution mixed occurred when the number of membranes is reduced, with the lowest number tested here being five membrane pairs. At this operating point, 0.32 kWh/m3 is extracted as electrical energy and 0.95 kWh/m3 as hydrogen energy. This corresponded to an electrical energy conversion efficiency of 15%, a hydrogen energy efficiency of 35%, and therefore, a total mixing energy efficiency of nearly 50%. As the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.6 W/m2 to 2.4 W/m2 at optimum external load. In contrast, the electrical power density increases from 0.84 W/m2 to 2.2 W/m2. Optimum operation of RED depends significantly on the external load (external device). A small load will increase hydrogen energy while decreasing electrical energy. This trade-off is critical in order to optimally operate an RED cell for both hydrogen and electricity generation.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.


Nijmeijer, K. , and Metz, S. , 2010, “ Salinity Gradient Energy,” Sustainability Sci. Eng., 2, pp. 95–139.
Alvarez-Silva, O. , Osorio, A. , and Winter, C. , 2016, “ Practical Global Salinity Gradient Energy Potential,” Renewable Sustainable Energy Rev., 60, pp. 1387–1395. [CrossRef]
Logan, B. E. , and Elimelech, M. , 2012, “ Membrane-Based Processes for Sustainable Power Generation Using Water,” Nature, 488(7411), pp. 313–319. [CrossRef] [PubMed]
Lee, K. P. , Arnot, T. C. , and Mattia, D. , 2011, “ A Review of Reverse Osmosis Membrane Materials for Desalination-Development to Date and Future Potential,” J. Membr. Sci., 370(1), pp. 1–22. [CrossRef]
Yip, N. Y. , and Elimelech, M. , 2012, “ Thermodynamic and Energy Efficiency Analysis of Power Generation From Natural Salinity Gradients by Pressure Retarded Osmosis,” Environ. Sci. Technol., 46(9), pp. 5230–5239. [CrossRef] [PubMed]
Straub, A. P. , Deshmukh, A. , and Elimelech, M. , 2016, “ Pressure-Retarded Osmosis for Power Generation From Salinity Gradients: Is It Viable?” Energy Environ. Sci., 9(1), pp. 31–48. [CrossRef]
Brogioli, D. , 2009, “ Extracting Renewable Energy From a Salinity Difference Using a Capacitor,” Phys. Rev. Lett., 103(5), p. 058501. [CrossRef] [PubMed]
Sales, B. , Saakes, M. , Post, J. , Buisman, C. , Biesheuvel, P. , and Hamelers, H. , 2010, “ Direct Power Production From a Water Salinity Difference in a Membrane-Modified Supercapacitor Flow Cell,” Environ. Sci. Technol., 44(14), pp. 5661–5665. [CrossRef] [PubMed]
Brogioli, D. , Ziano, R. , Rica, R. , Salerno, D. , and Mantegazza, F. , 2013, “ Capacitive Mixing for the Extraction of Energy From Salinity Differences: Survey of Experimental Results and Electrochemical Models,” J. Colloid Interface Sci., 407, pp. 457–466. [CrossRef] [PubMed]
Hatzell, M. C. , Ivanov, I. , Cusick, R. D. , Zhu, X. , and Logan, B. E. , 2014, “ Comparison of Hydrogen Production and Electrical Power Generation for Energy Capture in Closed-Loop Ammonium Bicarbonate Reverse Electrodialysis Systems,” Phys. Chem. Chem. Phys., 16(4), pp. 1632–1638. [CrossRef] [PubMed]
Hatzell, M. C. , and Zhu, X. , 2014, “ Simultaneous Hydrogen Generation and Waste Acid Neutralization in a Reverse Electrodialysis System,” ACS Sustainable Chem. Eng., 2(9), pp. 2211–2216. [CrossRef]
Veerman, J. , Saakes, M. , Metz, S. , and Harmsen, G. , 2009, “ Reverse Electrodialysis: Performance of a Stack With 50 Cells on the Mixing of Sea and River Water,” J. Membr. Sci., 327(1), pp. 136–144. [CrossRef]
Vermaas, D. A. , Saakes, M. , and Nijmeijer, K. , 2011, “ Doubled Power Density From Salinity Gradients at Reduced Intermembrane Distance,” Environ. Sci. Technol., 45(16), pp. 7089–7095. [CrossRef] [PubMed]
Długołȩcki, P. , Gambier, A. , Nijmeijer, K. , and Wessling, M. , 2009, “ Practical Potential of Reverse Electrodialysis as Process for Sustainable Energy Generation,” Environ. Sci. Technol., 43(17), pp. 6888–6894. [CrossRef] [PubMed]
Brauns, E. , 2009, “ Salinity Gradient Power by Reverse Electrodialysis: Effect of Model Parameters on Electrical Power Output,” Desalination, 237(1), pp. 378–391. [CrossRef]
Veerman, J. , Saakes, M. , Metz, S. , and Harmsen, G. , 2011, “ Reverse Electrodialysis: A Validated Process Model for Design and Optimization,” Chem. Eng. J., 166(1), pp. 256–268. [CrossRef]
Yip, N. Y. , Vermaas, D. A. , Nijmeijer, K. , and Elimelech, M. , 2014, “ Thermodynamic, Energy Efficiency, and Power Density Analysis of Reverse Electrodialysis Power Generation With Natural Salinity Gradients,” Environ. Sci. Technol., 48(9), pp. 4925–4936. [CrossRef] [PubMed]
Post, J. W. , Hamelers, H. V. , and Buisman, C. J. , 2008, “ Energy Recovery From Controlled Mixing Salt and Fresh Water With a Reverse Electrodialysis System,” Environ. Sci. Technol., 42(15), pp. 5785–5790. [CrossRef] [PubMed]
Veerman, J. , Saakes, M. , Metz, S. J. , and Harmsen, G. J. , 2010, “ Electrical Power From Sea and River Water by Reverse Electrodialysis: A First Step From the Laboratory to a Real Power Plant,” Environ. Sci. Technol., 44(23), pp. 9207–9212. [CrossRef] [PubMed]
Hong, J. G. , Zhang, B. , Glabman, S. , Uzal, N. , Dou, X. , Zhang, H. , Wei, X. , and Chen, Y. , 2015, “ Potential Ion Exchange Membranes and System Performance in Reverse Electrodialysis for Power Generation: A Review,” J. Membr. Sci., 486, pp. 71–88. [CrossRef]
Robinson, R. A. , and Stokes, R. H. , 1955, Electrolyte Solutions: The Measurement and Interpretation of Conductance, Chemical Potential and Diffusion in Solutions of Simple Electrolytes, Butterworths, Mineola, NY.
Dlugolkecki, P. , Ogonowski, P. , Metz, S. J. , Saakes, M. , Nijmeijer, K. , and Wessling, M. , 2010, “ On the Resistances of Membrane, Diffusion Boundary Layer and Double Layer in Ion Exchange Membrane Transport,” J. Membr. Sci., 349(1), pp. 369–379. [CrossRef]
Brauns, E. , 2008, “ Towards a Worldwide Sustainable and Simultaneous Large-Scale Production of Renewable Energy and Potable Water Through Salinity Gradient Power by Combining Reversed Electrodialysis and Solar Power?” Desalination, 219(1), pp. 312–323. [CrossRef]


Grahic Jump Location
Fig. 1

Reverse electrodialysis system for electricity and hydrogen gas generation. Hydrogen is produced at the cathode through a proton reduction reaction.

Grahic Jump Location
Fig. 2

Area-specific resistance (ASR) of the RED stack and its components (i.e., CEM, AEM, LC solution, and HC solution) and load as a function of moles of salt permeated across IEMs: (a) five membrane pairs, (b) 10 membrane pairs, and (c) 20 membrane pairs. IEMs include CEMs and AEMs. The total indicates overall RED stack resistance. Load is held constant during each analysis (6.35, 42.89, and 130.18 Ω cm2 for 5, 10, and 20 membrane pairs).

Grahic Jump Location
Fig. 3

(a) Moles of hydrogen, nH2, produced through RED stack and current density, i, and (b) hydrogen power density, PDH2, as a function of moles of salt permeated across IEMs for 5, 10, and 20 membrane pairs

Grahic Jump Location
Fig. 4

(a) Stack voltage, ξstack, and potential difference across the external load, ξL, and (b) maximum extractable energy (Gibbs free energy), Eideal, and electrical energy, Eelectrical, as a function of moles of salt permeated across IEMs for 5, 10, and 20 membrane pairs

Grahic Jump Location
Fig. 5

(a) Hydrogen and electrical power density, PD, (b) ideal energy (Gibbs free energy), Eideal, and (c) electrical and hydrogen energy extracted through RED stack as a function of normalized time area, t, for 5, 10, and 20 membrane pairs




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In