Journal of the Korean Electrochemical Society (전기화학회지)

The Korean Electrochemical Society (한국전기화학회)
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Understanding Thermodynamics of Operating Voltage and Efficiency in PEM Water Electrolysis System for Carbon Neutrality and Green Hydrogen Energy Transition

탄소중립과 그린 수소에너지 전환을 위한 PEM 수전해 시스템에서 작동 전압 및 효율의 열역학적 이해

  • HyungKuk Ju (Department of Energy Engineering, Dankook University) ;
  • Sungyool Bong (Department of Chemistry Education, Kongju National University) ;
  • Seungyoung Park (Department of Energy Engineering, Dankook University) ;
  • Chang Hyun Lee (Department of Energy Engineering, Dankook University)
  • 주형국 (단국대학교 과학기술대학 에너지공학과) ;
  • 봉성율 (공주대학교 화학교육과) ;
  • 박승용 (단국대학교 과학기술대학 에너지공학과) ;
  • 이창현 (단국대학교 과학기술대학 에너지공학과)
  • Received : 2023.11.06
  • Accepted : 2023.11.10
  • Published : 2023.11.30
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Abstract

The development of renewable energy technologies, such as solar, wave, and wind power, has led to the diversification of water electrolysis technologies, which can be easily coupled with renewable energy sources in terms of economics and scale. Water electrolysis technologies can be classified into three types based on operating temperature: low-temperature (<100 ℃), medium-temperature (300-700 ℃), and high-temperature (>700 ℃). It can also be classified by the type of electrolyte membrane used in the system. However, the concepts of thermodynamic and thermo-neutral voltages calculations and are very important factors in the evaluation of energy consumption and efficiency of water electrolysis technologies, are often confused. This review aims to contribute to a better understanding of the calculation of operating voltage and efficiency of PEM water electrolysis technologies and to clarify the differences between thermodynamic voltage and thermo-neutral voltage.

태양, 파도, 바람 등 친환경 재생에너지원을 이용한 전력 생산 기술이 성숙함에 따라 재생에너지 전력의 경제성과 규모 측면에서 빠르게 발전하고 있다. 특히, 전기화학적인 방법으로 수소를 생산하는 기술은 이러한 재생에너지와 효율적으로 연계될 수 있는 방법 중 하나로 주목받고 있다. 수전해 기술은 작동 온도에 따라서 저온(100 ℃ 이하), 중온(300-700 ℃), 고온(700 ℃ 이상) 수전해로 나눌 수 있으며, 에너지 소비량 및 전압 효율 평가는 열역학 법칙에 따라 계산한다. 그러나 수전해 평가에서 열역학적 전압(thermodynamic voltage)과 열중성 전압(thermo-neutral voltage)의 개념이 혼용되어 사용되고 있다. 본 총설에서는 저온 PEM (proton exchange membrane) 수전해 기술을 바탕으로 작동 전압과 효율 평가에 대한 이해를 높이고, 열역학적 전압과 열중성 전압의 차이점을 명확히 하고자 한다.

Keywords

Acknowledgement

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government (MOTIE) (RS-2023-00241035, 1415188062, Clean Hydrogen and Ammonia Innovation Research Center).

References

  1. S. Giddey, S. P. S. Badwal, and H. Ju, Polymer electrolyte membrane technologies integrated with renewable energy for hydrogen production, in: Current Trends and Future Developments on (Bio-) Membranes, pp. 235-259, Elsevier (2019).
  2. H. Ju, D. H. Seo, S. Chung, X. Mao, B.-S. An, M. Musameh, T. R. Gengenbach, H. Shon, A. Du, A. Bendavid, K. Ostrikov, H. C. Yoon, J. Lee, and S. Giddey, Green ammonia synthesis using CeO2/RuO2 nanolayers on vertical graphene catalyst via electrochemical route in alkaline electrolyte, Nanoscale, 14(4), 1395-1408 (2022). https://doi.org/10.1039/D1NR06411H
  3. IRENA, World Energy Transitions Outlook 2023, https://www.irena.org/Digital-Report/World-EnergyTransitions-Outlook-2023 (accessed October 6, 2023).
  4. Enerdata, 세계에너지소비통계, https://yearbook.enerdata.co.kr/total-energy/world-consumption-statistics.html (accessed October 6, 2023).
  5. H. Ju, S. Badwal, and S. Giddey, A comprehensive review of carbon and hydrocarbon assisted water electrolysis for hydrogen production, Appl. Energy, 231, 502-533 (2018). https://doi.org/10.1016/j.apenergy.2018.09.125
  6. W. Choi and S. Kang, Greenhouse gas reduction and economic cost of technologies using green hydrogen in the steel industry, J. Environ. Manag., 335, 117569 (2023).
  7. IRENA&ACE, Renewable Energy Outlook for ASEAN: a REmap Analysis, International Renewable Energy Agency (IRENA), Abu Dhabi and ASEAN Centre for Energy (ACE), Jakarta (2016), http://www.irena.org/menu/index.aspx?mnu=Subcat&PriMenuID=36&CatID=141&SubcatID=3751 (accessed October 6, 2023).
  8. T. D. Rapson, C. M. Gregg, R. S. Allen, H. Ju, C. M. Doherty, X. Mulet, S. Giddey, and C. C. Wood, Insights into nitrogenase bioelectrocatalysis for green ammonia production, ChemSusChem, 13(18), 4856-4865 (2020). https://doi.org/10.1002/cssc.202001433
  9. U.S. National Clean Hydrogen Strategy and Roadmap, https://www.hydrogen.energy.gov/library/roadmapsvision/clean-hydrogen-strategy-roadmap (accessed October 23, 2023).
  10. KPMG, Geographic hydrogen hotspots, https://kpmg.com/xx/en/home/insights/2021/01/geographichydrogen-hotspots.html (accessed October 23, 2023).
  11. Aramco, How can we deliver one of the fuels of the future?, https://www.aramco.com/en/campaigns/powered-by-how/blue-hydrogen?gclid=CjwKCAjwkNOpBhBEEiwAb3MvvYbiNiREt1TBOauPv3TsBavxlG6znFSKCFtJEFXRDrRy8Ami_21-LhoC878QAvD_BwE (accessed October 23, 2023).
  12. 이재훈, 조원철, 김창희, 수전해용 분리막 연구 동향 및 전망, 공업화학전망, 24(4), 1-21 (2021).
  13. J. Kim and K. Lee, Research trend in electrocatalysts for anion exchange membrane water electrolysis, J. Korean Electrochem. Soc., 25(2), 69-80 (2022).
  14. 김혜성, 송락현, 박석주, 이승복, 홍종은, 조동우, 임탁형, 프로톤 전도성 세라믹 기반 고온 수전해 기술 개요, New & Information for Chemical Engineers, 39(4), 378 (2021).
  15. C. Lamy and P. Millet, A critical review on the definitions used to calculate the energy efficiency coefficients of water electrolysis cells working under near ambient temperature conditions, J. Power Sources, 447, 227350 (2020).
  16. A. Rahbari, R. Hartkamp, O. A. Moultos, A. Bos, L. J. P. van den Broeke, M. Ramdin, D. Dubbeldam, A. V. Lyulin, and T. J. H. Vlugt, Electro-osmotic drag and thermodynamic properties of water in hydrated nafion membranes from molecular dynamics, J. Phys. Chem. C, 126(18), 8121-8133 (2022). https://doi.org/10.1021/acs.jpcc.2c01226
  17. P. Millet, Fundamentals of water electrolysis, in: A. Godula-Jopek (ed.), Hydrogen Production, pp. 33-62, John Wiley & Sons, Ltd (2015).
  18. S. P. S. Badwal, S. Giddey, and C. Munnings, Hydrogen production via solid electrolytic routes, WENE, 2(5), 473-487 (2013). https://doi.org/10.1002/wene.50
  19. K. W. Harrison, R. Remick, A. Hoskin, and G. D. Martin, Hydrogen Production: Fundamentals and Case Study Summaries; Preprint, National Renewable Energy Lab. (NREL), Golden, United States (2010), https://www.osti.gov/biblio/971440 (accessed October 19, 2023).
  20. P. Lettenmeier, Voltage Efficiency - White paper, Siemens Energy Global GmbH & Co. KG, Germany (2021).