Application of the cylindrical model to predict subsidence at Ngatamariki geothermal, New Zealand

Geothermal energy is one of the clean energies which several countries in the world use for the generation of electricity. However، geothermal energy plants have some environmental effects such as air and noise pollutions and subsidence. In this study، a cylindrical model was developed to predict subsidence at Ngatamariki geothermal plants، News Zealand. The Ngatamariki geothermal field is situated 17 km north east of Taupo. Mighty River Power has announced plans to build an 82 MW power station on the field. An extensive program of drilling، testing and modelling was performed to provide an understanding of the likely response of the field to the subsidence. A graphic program using Delphi high-level programming was developed to predict the subsidence. The results of the study show that the predicted subsidence has an agreement with subsidence data. A sensitivity analysis was carried out that shows the thermal expansion coefficient has a significant effect on increasing subsidence