Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production

Hydrogen production via water electrolysis and renewable electricity is expected to play a pivotal role as an energy carrier in the energy transition. This fuel emerges as the most environmentally sustainable energy vector for non-electric applications and is devoid of CO<sub>2</sub> emi...

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Main Authors: Alessandro Lima, Jorge Torrubia, Alicia Valero, Antonio Valero
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/6/1398
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author Alessandro Lima
Jorge Torrubia
Alicia Valero
Antonio Valero
author_facet Alessandro Lima
Jorge Torrubia
Alicia Valero
Antonio Valero
author_sort Alessandro Lima
collection DOAJ
description Hydrogen production via water electrolysis and renewable electricity is expected to play a pivotal role as an energy carrier in the energy transition. This fuel emerges as the most environmentally sustainable energy vector for non-electric applications and is devoid of CO<sub>2</sub> emissions. However, an electrolyzer’s infrastructure relies on scarce and energy-intensive metals such as platinum, palladium, iridium (PGM), silicon, rare earth elements, and silver. Under this context, this paper explores the exergy cost, i.e., the exergy destroyed to obtain one kW of hydrogen. We disaggregated it into non-renewable and renewable contributions to assess its renewability. We analyzed four types of electrolyzers, alkaline water electrolysis (AWE), proton exchange membrane (PEM), solid oxide electrolysis cells (SOEC), and anion exchange membrane (AEM), in several exergy cost electricity scenarios based on different technologies, namely hydro (HYD), wind (WIND), and solar photovoltaic (PV), as well as the different International Energy Agency projections up to 2050. Electricity sources account for the largest share of the exergy cost. Between 2025 and 2050, for each kW of hydrogen generated, between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.38</mn></mrow></semantics></math></inline-formula> and 1.22 kW will be required for the SOEC-hydro combination, while between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.9</mn></mrow></semantics></math></inline-formula> and 1.4 kW will be required for the PV-PEM combination. A Grassmann diagram describes how non-renewable and renewable exergy costs are split up between all processes. Although the hybridization between renewables and the electricity grid allows for stable hydrogen production, there are higher non-renewable exergy costs from fossil fuel contributions to the grid. This paper highlights the importance of non-renewable exergy cost in infrastructure, which is required for hydrogen production via electrolysis and the necessity for cleaner production methods and material recycling to increase the renewability of this crucial fuel in the energy transition.
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spelling doaj-art-e61dd69ae1124bd1ad6425d9ad4574f42025-08-20T02:42:38ZengMDPI AGEnergies1996-10732025-03-01186139810.3390/en18061398Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen ProductionAlessandro Lima0Jorge Torrubia1Alicia Valero2Antonio Valero3Research Institute for Energy and Resource Efficiency of Aragón (ENERGAIA), University of Zaragoza, Campus Río Ebro, Ed. CIRCE, c/ Mariano Esquillor Gómez 15, 50018 Zaragoza, SpainResearch Institute for Energy and Resource Efficiency of Aragón (ENERGAIA), University of Zaragoza, Campus Río Ebro, Ed. CIRCE, c/ Mariano Esquillor Gómez 15, 50018 Zaragoza, SpainResearch Institute for Energy and Resource Efficiency of Aragón (ENERGAIA), University of Zaragoza, Campus Río Ebro, Ed. CIRCE, c/ Mariano Esquillor Gómez 15, 50018 Zaragoza, SpainResearch Institute for Energy and Resource Efficiency of Aragón (ENERGAIA), University of Zaragoza, Campus Río Ebro, Ed. CIRCE, c/ Mariano Esquillor Gómez 15, 50018 Zaragoza, SpainHydrogen production via water electrolysis and renewable electricity is expected to play a pivotal role as an energy carrier in the energy transition. This fuel emerges as the most environmentally sustainable energy vector for non-electric applications and is devoid of CO<sub>2</sub> emissions. However, an electrolyzer’s infrastructure relies on scarce and energy-intensive metals such as platinum, palladium, iridium (PGM), silicon, rare earth elements, and silver. Under this context, this paper explores the exergy cost, i.e., the exergy destroyed to obtain one kW of hydrogen. We disaggregated it into non-renewable and renewable contributions to assess its renewability. We analyzed four types of electrolyzers, alkaline water electrolysis (AWE), proton exchange membrane (PEM), solid oxide electrolysis cells (SOEC), and anion exchange membrane (AEM), in several exergy cost electricity scenarios based on different technologies, namely hydro (HYD), wind (WIND), and solar photovoltaic (PV), as well as the different International Energy Agency projections up to 2050. Electricity sources account for the largest share of the exergy cost. Between 2025 and 2050, for each kW of hydrogen generated, between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.38</mn></mrow></semantics></math></inline-formula> and 1.22 kW will be required for the SOEC-hydro combination, while between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.9</mn></mrow></semantics></math></inline-formula> and 1.4 kW will be required for the PV-PEM combination. A Grassmann diagram describes how non-renewable and renewable exergy costs are split up between all processes. Although the hybridization between renewables and the electricity grid allows for stable hydrogen production, there are higher non-renewable exergy costs from fossil fuel contributions to the grid. This paper highlights the importance of non-renewable exergy cost in infrastructure, which is required for hydrogen production via electrolysis and the necessity for cleaner production methods and material recycling to increase the renewability of this crucial fuel in the energy transition.https://www.mdpi.com/1996-1073/18/6/1398hydrogen generationwater electrolysiselectricity scenarioscleaner productionexergy costrenewable energy
spellingShingle Alessandro Lima
Jorge Torrubia
Alicia Valero
Antonio Valero
Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production
Energies
hydrogen generation
water electrolysis
electricity scenarios
cleaner production
exergy cost
renewable energy
title Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production
title_full Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production
title_fullStr Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production
title_full_unstemmed Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production
title_short Non-Renewable and Renewable Exergy Costs of Water Electrolysis in Hydrogen Production
title_sort non renewable and renewable exergy costs of water electrolysis in hydrogen production
topic hydrogen generation
water electrolysis
electricity scenarios
cleaner production
exergy cost
renewable energy
url https://www.mdpi.com/1996-1073/18/6/1398
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AT jorgetorrubia nonrenewableandrenewableexergycostsofwaterelectrolysisinhydrogenproduction
AT aliciavalero nonrenewableandrenewableexergycostsofwaterelectrolysisinhydrogenproduction
AT antoniovalero nonrenewableandrenewableexergycostsofwaterelectrolysisinhydrogenproduction