Dissertation
CARBON NEUTRAL SYNTHETIC NATURAL GAS GENERATION BY SOLID OXIDE ELECTROLYSIS OF STEAM AND CARBON DIOXIDE: AN ECONOMIC AND EXPERIMENTAL STUDY
Doctor of Philosophy (PhD), Washington State University
07/2025
DOI:
https://doi.org/10.7273/000007902
Abstract
Power-to-Gas (PtG), the conversion of renewable electricity into gaseous fuels for storage, represents a promising solution to reduce carbon emissions in global energy sectors when coupled with solid oxide electrolysis cell (SOEC) technology. In the present work, an economic study was conducted comparing energy storage pathways to decarbonize the US power sector, followed by a complementary experimental study on pressurized co-electrolysis of steam and carbon dioxide to produce methane directly for improved SNG generation rates. The optimization model found that widespread installations of solar can reduce carbon emissions to 48% of present-day levels with a 1 $/MWh impact on energy prices if interconnection limitations are neglected. Key findings reveal that, in a fully decarbonized electric power sector, SNG is the most economically viable energy storage medium by utilizing existing NG pipelines and infrastructure for seasonal storage and distribution of energy. In comparison to Li-ion battery technology, this translates to savings of 28% to end use customers. SOEC experiments at 650ºC and 30 bar resulted in an electrolytic current density of 0.87 A/cm2 at a DC polarization of 1.2V under co-electrolysis conditions through the application of a novel steam delivery design. It was found that increasing the pressure from 10 bar to 30 bar at 650ºC resulted in an increase in methane measurements of over four times from 0.3% to 1.3%. Faradaic efficiencies ranged from 4% at 700ºC and 30 bar to 45% at 700ºC and 10 bar. The low faradaic efficiencies appear anomalous and, upon further study, may have been impacted by a significant leak in the silver sealant at the cathode.
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Details
- Title
- CARBON NEUTRAL SYNTHETIC NATURAL GAS GENERATION BY SOLID OXIDE ELECTROLYSIS OF STEAM AND CARBON DIOXIDE
- Creators
- Cameron Bennethum
- Contributors
- Min-Kyu Song (Chair)Mehdi Hosseinzadeh (Committee Member)Soumik Banerjee (Committee Member)Dustin McLarty (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 121
- Identifiers
- 99901297980001842
- Language
- English
- Resource Type
- Dissertation