The conductive geothermal field as an energy and economic entity
|PhD ceremony:||Mr A. (Alex) Daniilidis|
|When:||October 27, 2017|
|Supervisor:||prof. M.A. (Rien) Herber|
|Where:||Academy building RUG|
|Faculty:||Science and Engineering|
Geothermal sources provide renewable energy that can be used for electricity or heat generation. This thesis is aimed at identifying and analyzing potential geothermal heat generation in NE Netherlands in two different ways. The first explores the use of the high heat flow through underground salt layers. The second is a step-wise analysis for evaluating the development of the Groningen city geothermal system.
The high thermal conductivity of salt in comparison with other sediments makes access to the heat resource easier (in terms of capacity, time and, most critically for geothermal projects, cost) and improves its renewability (by means of higher heat supply through the salt). Directly above the salt, increased temperatures were modelled up to 25˚C in comparison with other sediments at the same depth. Up to 40% more energy can be extracted from such systems compared to ones without a high salt thickness.
For the Groningen city geothermal system, the analysis considers the uncertainties at different levels. Firstly, the uncertainties of geology and operational aspects are considered to estimate the potential energy generation. Next, the system behavior to changes in heat demand is evaluated and the geochemical aspects are discussed. Lastly, a technical and economic model is used to investigate the economic performance of the system overall. The demand throughout the season proves to be a significant aspect of economic performance. Additionally, changing the timing of the developments steps and an adjustment of the subsidy scheme can significantly improve economic performance