TITLE:
Conventional Geothermal Systems and Unconventional Geothermal Developments: An Overview
AUTHORS:
Maryam Khodayar, Sveinbjörn Björnsson
KEYWORDS:
Conventional Geothermal Systems, Unconventional Geothermal Developments, Shallow and Deep Closed-Loops, Enhanced Geothermal Systems, Supercritical and Millimeter-Wave Drilling
JOURNAL NAME:
Open Journal of Geology,
Vol.14 No.2,
February
20,
2024
ABSTRACT: This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal systems have the heat, permeability and fluid, requiring only drilling down to °C, normal heat flow or decaying radiogenic granite as heat sources, and used in district heating. Medium-temperature (MT) 100°C - 190°C, and high-temperature (HT) 190°C - 374°C resources are mostly at plate boundaries, with volcanic intrusive heat source, used mostly for electricity generation. Single well capacities are °C - 500°C) and a range of depths (1 m to 20 Km), but lack permeability or fluid, thus requiring stimulations for heat extraction by conduction. HVAC is 1 - 2 m deep and shallow geothermal down to 500 m in wells, both capturing °C, with °C are either advanced by geothermal developers at