APPLICABILITY AND SUSTAINABILITY OF SEAWATER INJECTION IN ORDER TO PRODUCE GEOTHERMAL ENERGY

The biggest problems in today’s world are shaping around energy topic. Energy importing countries are investing in renewable energy sources and they are planning to minimise energy import in future. Comparing with the other renewable energy sources, geothermal energy is more efficient, environmental friendly and sustainable. One of the most crucial thing for sustainable using of a geothermal system is keeping the geothermal reservoir pressure and fluid temperature stable. With the development of re-injection technique, the potential decrease in the reservoir pressure has mainly been mitigated and therefore the sustainability of geothermal reservoir has been provided. On the other hand, Hot Dry Rock (HDR) technique is mainly built up to inject cold water in a deep, fractured, hot and dry rock formation and pump it back after heating via geothermal gradient of the earth where geothermal reservoir cannot be found. The aim of this paper is investigating the applicability of seawater injection into both HDR and geothermal reservoir technique in order to sustainable usage of a geothermal system.

The mass loss (from the extraction of vapour and hot water, during the usage of energy supply or agricultural and domestic heating to re-injection stage) in the geothermal cycle can be supplied with the use of sea water in order to recover the reservoir pressure at the beginning. Another technique is targeting to produce energy with partially or completely use of seawater injection and extraction from HDR where any productive geothermal reservoir cannot be found. In order to test the applicability of both techniques, the mixture models between two end members (seawater and geothermal water) can be modelled in different mixture ratios, different temperature and pressure by using hydro chemical modelling software. Especially, investigating the mineral solution-precipitation reactions between sea water-rock interaction processes in reservoir and borehole should be modelled as well.