Life Cycle Assessment of Green Hydrogen Production from Solar-Powered Electrolysis
DOI:
https://doi.org/10.5281/zenodo.22795246Keywords:
green hydrogen, life cycle assessment, solar photovoltaics, PEM electrolysis, alkaline electrolysis, carbon intensity, water footprint, land use;, blue hydrogen, hydrogen economyAbstract
Green hydrogen produced by coupling solar photovoltaic (PV) generation to water electrolysis is widely promoted
as a low-carbon substitute for fossil-derived hydrogen, yet cradle-to-gate comparisons that place it consistently
alongside grey, blue and grid-electrolysis pathways on carbon, water and land metrics simultaneously remain
scarce. We conducted an attributional cradle-to-gate life cycle assessment of hydrogen produced by dedicated
ground-mounted solar PV coupled to proton-exchange-membrane (PEM) and alkaline electrolysers at a reference
1000 kg H2 per day facility, using process data drawn from published electrolyser efficiency benchmarks, PV
module and balance-of-system inventories, and a 25-year system lifetime with a 22% PV capacity factor
representative of a low-latitude, high-irradiance site. Results were benchmarked against steam methane reforming
(SMR) without and with carbon capture and storage (grey and blue hydrogen), and against electrolysis powered by
grid-average electricity under two contrasting grid carbon intensities. Cradle-to-gate carbon intensity was 1.4 kg
CO2-eq per kg H2 for solar PV-PEM and 1.2 kg CO2-eq per kg H2 for solar PV-alkaline, compared with 11.2 for
grey hydrogen, 3.8 for blue hydrogen, 14.6 for grid-average electrolysis on a moderately decarbonised grid, and
39.2 for grid-average electrolysis on a coal-heavy grid. Water consumption was lowest for the two solar-electrolysis
pathways (11.7-12.2 L per kg H2) and highest for grid-average electrolysis (approximately 72 L per kg H2), driven
overwhelmingly by cooling-water withdrawal at thermal power stations rather than by the electrolysis process itself.
Land occupation showed the opposite ranking: dedicated solar PV required roughly fifteen times more land per
kilogram of hydrogen produced annually than any fossil or grid-average pathway, reflecting the low areal power
density of photovoltaic conversion. These results indicate that solar-powered electrolysis delivers a genuine,
substantial carbon and water advantage over both fossil and grid-average hydrogen pathways, but that this
advantage is accompanied by a land-use trade-off, and by carbon and water performance that is highly sensitive to
electrolyser stack lifetime, PV embodied emissions and site irradiance, none of which should be assumed
transferable across geographies without site-specific verification.
References
Griffiths S, Sovacool BK, Kim J, Bazilian M, Uratani JM (2021) Industrial decarbonization via hydrogen: a critical and systematic review of developments, socio-technical systems and policy options. Energy Research & Social Science 80:102208. https://doi.org/10.1016/j.erss.2021.102208
Longden T, Beck FJ, Jotzo F, Andrews R, Prasad M (2022) "Clean" hydrogen? Comparing the emissions and costs of fossil fuel versus renewable electricity based hydrogen. Applied Energy 306:118145. https://doi.org/10.1016/j.apenergy.2021.118145
Cetinkaya E, Dincer I, Naterer GF (2012) Life cycle assessment of various hydrogen production methods. International Journal of Hydrogen Energy 37(3):2071-2080. https://doi.org/10.1016/j.ijhydene.2011.10.064
Howarth RW, Jacobson MZ (2021) How green is blue hydrogen? Energy Science & Engineering 9(10):1676-1687. https://doi.org/10.1002/ese3.956
Bauer C, Treyer K, Antonini C, Bergerson J, Gazzani M, Gencer E, Gibbins J, Mazzotti M, McCoy ST, McKenna R, Pietzcker R, Ravikumar AP, Romano MC, Ueckerdt F, Vente J, van der Spek M (2022) On the climate impacts of blue hydrogen production. Sustainable Energy & Fuels 6:66-75. https://doi.org/10.1039/D1SE01508G
Parkinson B, Balcombe P, Speirs JF, Hawkes AD, Hellgardt K (2019) Levelized cost of CO2 mitigation from hydrogen production routes. Energy & Environmental Science 12:19-40. https://doi.org/10.1039/C8EE02079E
Terlouw T, Bauer C, McKenna R, Mazzotti M (2022) Large-scale hydrogen production via water electrolysis: a techno-economic and environmental assessment. Energy & Environmental Science 15:3583-3602. https://doi.org/10.1039/D2EE01023B
Fthenakis V, Kim HC (2011) Photovoltaics: life-cycle analyses. Solar Energy 85(8):1609-1628. https://doi.org/10.1016/j.solener.2009.10.002
Fthenakis VM, Kim HC, Alsema E (2008) Emissions from photovoltaic life cycles. Environmental Science & Technology 42(6):2168-2174. https://doi.org/10.1021/es071763q
de Wild-Scholten MJ (2013) Energy payback time and carbon footprint of commercial photovoltaic systems. Solar Energy Materials and Solar Cells 119:296-305. https://doi.org/10.1016/j.solmat.2013.08.037
Hernandez RR, Easter SB, Murphy-Mariscal ML, Maestre FT, Tavassoli M, Allen EB, Barrows CW, Belnap J, Ochoa-Hueso R, Ravi S, Allen MF (2014) Environmental impacts of utility-scale solar energy. Renewable and Sustainable Energy Reviews 29:766-779. https://doi.org/10.1016/j.rser.2013.08.041
Mehmeti A, Angelis-Dimakis A, Arampatzis G, McPhail S, Ulgiati S (2018) Life cycle assessment and water footprint of hydrogen production methods: from conventional to emerging technologies. Environments 5(2):24. https://doi.org/10.3390/environments5020024
Valente A, Iribarren D, Dufour J (2017) Life cycle assessment of hydrogen energy systems: a review of methodological choices. International Journal of Life Cycle Assessment 22:346-363. https://doi.org/10.1007/s11367-016-1156-z
Bhandari R, Trudewind CA, Zapp P (2014) Life cycle assessment of hydrogen production via electrolysis - a review. Journal of Cleaner Production 85:151-163. https://doi.org/10.1016/j.jclepro.2013.07.048
Shiva Kumar S, Himabindu V (2019) Hydrogen production by PEM water electrolysis - a review. Materials Science for Energy Technologies 2(3):442-454. https://doi.org/10.1016/j.mset.2019.03.002
Buttler A, Spliethoff H (2018) Current status of water electrolysis for energy storage, grid balancing and sector coupling via power-to-gas and power-to-liquids: a review. Renewable and Sustainable Energy Reviews 82:2440-2454. https://doi.org/10.1016/j.rser.2017.09.003
Koj JC, Wulf C, Schreiber A, Zapp P (2017) Site-dependent environmental impacts of industrial hydrogen production by alkaline water electrolysis. Energies 10(7):860. https://doi.org/10.3390/en10070860
Suleman F, Dincer I, Agelin-Chaab M (2015) Environmental impact assessment and comparison of some hydrogen production options. International Journal of Hydrogen Energy 40(21):6976-6987. https://doi.org/10.1016/j.ijhydene.2015.03.123
Bareiss K, de la Rua C, Mockl M, Hamacher T (2019) Life cycle assessment of hydrogen from proton exchange membrane water electrolysis in future energy systems. Applied Energy 237:862-872. https://doi.org/10.1016/j.apenergy.2019.01.001
Schmidt O, Gambhir A, Staffell I, Hawkes A, Nelson J, Few S (2017) Future cost and performance of water electrolysis: an expert elicitation study. International Journal of Hydrogen Energy 42(52):30470-30492. https://doi.org/10.1016/j.ijhydene.2017.10.045
Gallardo FI, Monforti Ferrario A, Lamagna M, Bocci E, Astiaso Garcia D, Baeza-Jeria TE (2021) A techno-economic analysis of solar hydrogen production by electrolysis: a comparison with hydrogen production from natural gas and coal. International Journal of Hydrogen Energy 46(26):13709-13728. https://doi.org/10.1016/j.ijhydene.2020.07.050
Al-Qahtani A, Parkinson B, Hellgardt K, Shah N, Guillen-Gosalbez G (2021) Uncovering the true cost of hydrogen production routes using life cycle monetisation. Applied Energy 281:115958. https://doi.org/10.1016/j.apenergy.2020.115958
Nugent D, Sovacool BK (2014) Assessing the lifecycle greenhouse gas emissions from solar PV and wind energy: a critical meta-survey. Energy Policy 65:229-244. https://doi.org/10.1016/j.enpol.2013.10.048
van Renssen S (2020) The hydrogen solution? Nature Climate Change 10:799-801. https://doi.org/10.1038/s41558-020-0891-0
Frank ED, Elgowainy A, Reddi K, Bafana A (2021) Life cycle analysis of greenhouse gas emissions from renewable hydrogen production via electrolysis. Environmental Science & Technology 55(13):8930-8938. https://doi.org/10.1021/acs.est.0c07640
