Techno-economic analysis of Advanced Geothermal Systems (AGS)

Advanced Geothermal Systems (AGS) generate electric power through a closed-loop circuit, after a working fluid extracts thermal energy from rocks at great depths via conductive heat transfer from the geologic formation to the working fluid through an impermeable wellbore wall. The slow conductive he...

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Bibliographic Details
Published in:Renewable energy 2022-03, Vol.186, p.927-943
Main Authors: Malek, Adam E., Adams, Benjamin M., Rossi, Edoardo, Schiegg, Hans O., Saar, Martin O.
Format: Article
Language:English
Subjects:
Advanced geothermal systems
Closed-loop
Electric power generation
Geothermal energy
Renewable energy
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Summary:Advanced Geothermal Systems (AGS) generate electric power through a closed-loop circuit, after a working fluid extracts thermal energy from rocks at great depths via conductive heat transfer from the geologic formation to the working fluid through an impermeable wellbore wall. The slow conductive heat transfer rate present in AGS, compared to heat advection, makes AGS uneconomical to this date. To investigate what would be required to render AGS economical, we numerically model an example AGS using the genGEO simulator to obtain its electric power generation and its specific capital cost. Our numerical results show that using CO2 as the working fluid benefits AGS performance. Additionally, we find that there exists a working fluid mass flowrate, a lateral well length, and a wellbore diameter which minimize AGS costs. However, our results also show that AGS remain uneconomical with current, standard drilling technologies. Therefore, significant advancements in drilling technologies, that have the potential to reduce drilling costs by over 50%, are required to enable cost-competitive AGS implementations. Despite these challenges, the economic viability and societal acceptance potential of AGS are significantly raised when considering that negative externalities and their costs, so common for most other power plants, are practically non-existent with AGS.
ISSN:0960-1481
1879-0682
DOI:10.1016/j.renene.2022.01.012