Project AEGIS-CH Description

Why AEGIS-CH?

AEGIS-CH is an Innosuisse Flagship project with the aim to improve the resilience of the Swiss energy system through the development and integration of Advanced Geothermal Systems (AGS). AGS, consisting of closed-loop wells without any hydraulic stimulation, have the potential to provide decarbonized, domestic and decentralized heat and electric power. This enables firming up an increasingly solar/wind (and thus largely only intermittently available) Swiss energy supply system, supporting the Swiss Energy Transition Strategy (SETS) 2050 as well as UN Sustainable Development Goals. Together with our academic and industry partners, new technology is developed to construct closed-loop AGS and the potential of AGS is explored in the context of the optimal energy mix. This integrated concept leads to essential AGS developments, energy policy recommendations for Switzerland and new energy business models.

AGS

Advanced Geothermal Systems (AGS) are a novel geothermal energy (GE) technology, where a working fluid circulates in a deep, closed well loop to collect heat by conduction with the surrounding hot rock [[1],[2]]. At the surface, the extracted heat is used to generate electric/thermal power. AGS target comparable depth and temperature levels as Enhanced Geothermal Systems (EGS). EGS make use of hydraulic stimulation (hydraulic fracturing and/or shearing) of the reservoir rock to artificially enhance its (naturally low) permeability. Hydraulic stimulation operations are causing, by definition, at least small earthquakes. In contrast to EGS, AGS do not require such hydraulically stimulated permeability enhancements by e.g. “fracking”. Figure 2 (modified from [3]) compares the differences in layouts, constructions, and target depth of conventional hydrothermal systems (a), EGS (b) and AGS (c).
AGS can generate dispatchable and baseload power, without operational CO2 emissions. Moreover, the ubiquitous source of geothermal energy and the geology-independence of AGS enable CO2-emission-free, decentralized, autarkic energy supply, avoiding expensive power grids. Also, AGS have little external costs/impacts, further benefiting their long-term social and environmental sustainability.


 
Figure 1: AEGIS-CH includes both a Swiss-wide “I. Energy System Analysis” and “II. AGS Development”. Left: Illustration of a potential (future) Switzerland’s energy supply system (SESS) landscape, where small red dots (many, small plants) represent the novel deep closed-loop systems, firming up the Swiss power supply while omitting any potential fossil-fueled power plants (in the shown case); Right: Schematics of AGS illustrating the concept of a deep, closed loop advanced geothermal system for local supply of dispatchable, baseload thermal and electric power.


 
Figure 2: Geothermal Energy generation technologies: (a) hydrothermal, (b) Enhanced Geothermal System (EGS) and (c) the novel deep closed-loop Advanced Geothermal Systems (AGS), figure modified from [3].

References

[1] Malek, A. E, Adams, B. M., Rossi, E., Schiegg, H. O., & Saar, M. O. (2021). Electric Power Generation, Specific Capital Cost, and Specific Power for Advanced Geothermal Systems (AGS). In: Proceedings of the 46th Workshop on Geothermal Reservoir Engineering, Stanford, CA. doi: 10.3929/ethz-b-000467172
[2] Van Oort, E., Chen, D., Ashok, P., & Fallah, A. (2021). Constructing Deep Closed-Loop Geothermal Wells for Globally Scalable Energy Production by Leveraging Oil and Gas ERD and HPHT Well Construction Expertise. In: SPE/IADC International Drilling Conference and Exhibition, Virtual, March 2021. doi: 10.2118/204097-MS
[3] Rangel-Jurado, N. (2021). Thermal performance evaluations of fractured and closed-loop geothermal reservoirs, MSc Thesis, 88 pp, Cornell University, USA.