Surface heat flow and CO2 emissions within the Ohaaki hydrothermal field, Taupo Volcanic Zone, New Zealand

Review on life cycle environmental effects of geothermal power generation

“…This is in line with observations from recent measurement campaigns, e.g. [41]. Long term decrease of natural GHG emissions through the surface are not accounted for.…”

“…Fridriksson et al [60] anticipate a six fold increase of CO 2 emissions by operation of the Reykjanes power plant in Iceland. In New Zealand (NZ), at the Ohaaki hydrothermal field, after 20 years of geothermal power production, soil degassing was intensively measured [41]. Main findings are that due to low-permeability of the reservoir spatial extent and magnitude of natural CO 2 emissions have not changed.…”

“…[40]. Ground deformations entail sometimes the creation of surface-near tensile fractures and fissures in the surrounding [41], which offer new pathways for gas and water circulation. Pasvanoğlu et al [42] even report formation of an extensive sinkhole as a consequence of intense hydrothermal water abstraction in a karst regime at the Kozakli geothermal field in Turkey.…”

Carbon dioxide diffuse emission and thermal energy release from hydrothermal systems at Copahue–Caviahue Volcanic Complex (Argentina)

“…Soil CO 2 fluxes higher than those due to biologic activity are indeed commonly associated with the circulation of hydrothermal fluids (Chiodini et al, 1998;Cardellini et al, 2003;Lewicki and Oldenburg, 2005). In addition, recent studies have shown that CO 2 diffuse degassing can provide important and reliable constraints for a correct evaluation of the geothermal potential from hydrothermal areas Fridriksson et al, 2006;Werner and Cardellini, 2006;Chiodini et al, 2007;Mazot and Taran, 2009;Hernández et al, 2012;Rissmann et al, 2012;Bloomberg et al, 2014;Granieri et al, 2014;Dionis et al, 2015). In particular, the total budget of hydrothermal gases released at the surface can be used for a robust estimation of the minimum amount of geothermal fluids involved at depth in the degassing process.…”

Three-dimensional model of the deep geothermal resources in the Taupo–Reporoa Basin, New Zealand

“…The heat flows given in the table are all taken from Bibby et al (1995) except for data from Hochstein (2007) for Waiotapu and Reporoa, and Rissmann et al (2012) for Ohaaki. Waimangu is included although only its western part falls within the model domain.…”