TY - JOUR
T1 - Geothermal energy in deep aquifers
T2 - A global assessment of the resource base for direct heat utilization
AU - Limberger, Jon
AU - Boxem, Thijs
AU - Pluymaekers, Maarten
AU - Bruhn, David
AU - Manzella, Adele
AU - Calcagno, Philippe
AU - Beekman, Fred
AU - Cloetingh, Sierd
AU - van Wees, Jan Diederik
PY - 2018/2/1
Y1 - 2018/2/1
N2 - In this paper we present results of a global resource assessment for geothermal energy within deep aquifers for direct heat utilization. Greenhouse heating, spatial heating, and spatial cooling are considered in this assessment. We derive subsurface temperatures from geophysical data and apply a volumetric heat-in-place method to improve current global geothermal resource base estimates for direct heat applications. The amount of thermal energy stored within aquifers depends on the Earth's heat flow, aquifer volume, and thermal properties. We assess the thermal energy available by estimating subsurface temperatures up to a depth of three kilometer depending on aquifer thickness. The distribution of geothermal resources is displayed in a series of maps and the depth of the minimum production temperature is used as an indicator of performance and technical feasibility. Suitable aquifers underlay 16% of the Earth's land surface and store an estimated 4·105 to 5·106 EJ that could theoretically be used for direct heat applications. Even with a conservative recovery factor of 1% and an assumed lifetime of 30 years, the annual recoverable geothermal energy is in the same order as the world final energy consumption of 363.5 EJ yr−1. Although the amount of geothermal energy stored in aquifers is vast, geothermal direct heat applications are currently underdeveloped with less than one thousandth of their technical potential used.
AB - In this paper we present results of a global resource assessment for geothermal energy within deep aquifers for direct heat utilization. Greenhouse heating, spatial heating, and spatial cooling are considered in this assessment. We derive subsurface temperatures from geophysical data and apply a volumetric heat-in-place method to improve current global geothermal resource base estimates for direct heat applications. The amount of thermal energy stored within aquifers depends on the Earth's heat flow, aquifer volume, and thermal properties. We assess the thermal energy available by estimating subsurface temperatures up to a depth of three kilometer depending on aquifer thickness. The distribution of geothermal resources is displayed in a series of maps and the depth of the minimum production temperature is used as an indicator of performance and technical feasibility. Suitable aquifers underlay 16% of the Earth's land surface and store an estimated 4·105 to 5·106 EJ that could theoretically be used for direct heat applications. Even with a conservative recovery factor of 1% and an assumed lifetime of 30 years, the annual recoverable geothermal energy is in the same order as the world final energy consumption of 363.5 EJ yr−1. Although the amount of geothermal energy stored in aquifers is vast, geothermal direct heat applications are currently underdeveloped with less than one thousandth of their technical potential used.
KW - Direct heat utilization
KW - Geothermal energy
KW - Global resources
KW - Heat flow
KW - Heat in place
UR - http://www.scopus.com/inward/record.url?scp=85030759456&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:1c8e9d67-84ca-4c9a-ad26-b76ab254c754
U2 - 10.1016/j.rser.2017.09.084
DO - 10.1016/j.rser.2017.09.084
M3 - Review article
AN - SCOPUS:85030759456
SN - 1364-0321
VL - 82
SP - 961
EP - 975
JO - Renewable & Sustainable Energy Reviews
JF - Renewable & Sustainable Energy Reviews
ER -