Comparing the net-energy balance of standalone photovoltaic-coupled electrolysis and photoelectrochemical hydrogen production
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Published version
Author(s)
Tam, Brian
Babacan, Oytun
Kafizas, Andreas
Nelson, Jenny
Type
Journal Article
Abstract
Photovoltaic-coupled electrolysis (PV-E) and photoelectrochemical (PEC) water splitting are two options for storing solar energy as hydrogen. Understanding the requirements for achieving a positive energy balance over the lifetime of facilities using these technologies is important for ensuring sustainability. While neither technology has yet reached full commercialisation, they are also at very different technology readiness levels and scales of development. Here, we model the energy balance of standalone large-scale facilities to evaluate their energy return on energy invested (ERoEI) over time and energy payback time (EPBT). We find that for average input parameters based on present commercialised modules, a PV-E facility shows an EPBT of 6.2 years and ERoEI after 20 years of 2.1, which rises to approximately 3.7 with an EPBT of 2.7 years for favourable parameters using the best metrics amongst large-scale modules. The energy balance of PV-E facilities is influenced most strongly by the upfront embodied energy costs of the photovoltaic component. In contrast, the simulated ERoEI for a PEC facility made with earth abundant materials only peaks at 0.42 after 11 years and about 0.71 after 20 years for facilities with higher-performance active materials. Doubling the conversion efficiency to 10% and halving the degradation rate to 2% for a 10-year device lifetime can allow PEC facilities to achieve an ERoEI after 20 years of 2.1 for optimistic future parameters. We also estimate that recycling the materials used in hydrogen production technologies improves the energy balance by 28% and 14% for favourable-case PV-E and PEC water splitting facilities, respectively.
Date Issued
2024-03-05
Date Acceptance
2024-01-12
Citation
Energy and Environmental Science, 2024, 17 (5), pp.1677-1694
ISSN
1754-5692
Publisher
Royal Society of Chemistry
Start Page
1677
End Page
1694
Journal / Book Title
Energy and Environmental Science
Volume
17
Issue
5
Copyright Statement
This journal is © The Royal Society of Chemistry 2024. Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Subjects
Chemistry
Chemistry, Multidisciplinary
CONVERSION
CRYSTALLINE
Energy & Fuels
Engineering
Engineering, Chemical
Environmental Sciences
Environmental Sciences & Ecology
Life Sciences & Biomedicine
LIFE-CYCLE ASSESSMENT
LIMITING EFFICIENCY
PAYBACK TIME
PERFORMANCE
Physical Sciences
Science & Technology
SOLAR
STORAGE
TECHNOECONOMIC ANALYSIS
Technology
WATER ELECTROLYSIS
Publication Status
Published
Date Publish Online
2024-01-15