Geothermal energy is a renewable energy source which has not yet had the same breakthrough as other renewables, e.g. solar PV and wind. There may still be some technical issues to be solved before geothermal can reach its full potential.One of these technical challenges concerns reinjection, i.e. the return of geothermal fluids back into the ground after surface energy extraction. In traditional geothermal energy utilization, hot geothermal fluid is brought up from underground reservoirs to the surface. Depending on the design of the power plant, the fluid can either be kept one-phased or get separated into two phases, i.e. hot steam and water. Hot steam, or vapor of another working fluid, is used to drive electricity generating turbines. Whether the condensate is returned back into to the ground after energy extraction, i.e. reinjected, is nowadays usually a matter of how rather than if. However, the magnitude and strategy varies in countries as well as for specific power plant operators.From a sustainable management perspective, the majority of operators as well as scientist agree that reinjection is the best way practice in order to take care of a resource and leave the smallest possible environmental footprint. However, it is a quite complicated and not always problem free operation. There are numerous examples where reinjection has led to complications such as scaling, induced seismicity and cooling of the reservoir. The purpose of this study was to describe the current status of geothermal reinjection from a neutral third-party perspective, e.g. by describing current obstacles and negative as well as positive outcomes. The aim is to conclude whether current technology is enough to successfully reinject, or if there are still some gaps of knowledge to fill. The method consists partly of a literature study of previously written technical reports but also of interviews with experts in the area. In addition, the study summarizes the legal framework regarding reinjection in some geothermal active countries, e.g. if it is required by law or not. Although currently technology is enough to do a fairly good job at reinjecting geothermal fluids, the result of the study also shows that there are still some technical barriers to overcome in order to fully optimize it. However, it remains the best currently known way to keep geothermal energy sustainable. Better technologies will be needed in order for geothermal to reach its fully green potential.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-383963 |
| Date | January 2019 |
| Creators | Skog, Gabriella |
| Publisher | Uppsala universitet, Institutionen för geovetenskaper |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Gabriella Skog |
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