Optimized pipe diameter and insulation thickness of long-distance heat interconnection pipelines

Deep geothermal energy has a tremendous potential for decarbonizing the European heating sector. Especially in urban areas, district heating networks driven by geothermal energy are a promising technology for a sustainable heat supply. However, while urban areas are favourable for district heating networks due to their high heat demand density, potential geologically suitable geothermal sites are not always located within or close to large cities. At the same time, the economic utilization of attractive geothermal reservoirs in rural and remote areas is often not feasible, due to the low local heat demand. Thus, potential promising sites are not utilized due to their limited economic potential. As demonstrated in a previous study for the region of South Bavaria (Germany), long-distance heat interconnection pipelines might be a promising solution to transport heat from geothermal sites in rural areas into urban areas. Such heat interconnection pipelines lead to two possible positive effects: Firstly, the contribution of geothermal energy to the decarbonization of the heating sector in metropolitan areas can be significantly increased. Secondly, the economic viability of geothermal projects in rural areas can be significantly improved by increasing the full load hours. Thus, more geothermal projects might be implemented. However, potential long-distance heat interconnection pipelines come along with high investment costs. Therefore, it is crucial to select the optimal pipe diameter and insulation thickness in order to ensure an optimal design. While higher pipe diameters and insulation thicknesses increase the investment costs, they decrease pressure losses and heat losses, respectively. Thus, there is a trade-off between the investment and operational costs. This study investigates the economic performance of long-distance heat interconnection pipelines. For a broad range of potential application scenarios concerning various distances, full-load hours, and temperature levels, the optimized pipe diameter and insulation thickness are determined.     «

Deep geothermal energy has a tremendous potential for decarbonizing the European heating sector. Especially in urban areas, district heating networks driven by geothermal energy are a promising technology for a sustainable heat supply. However, while urban areas are favourable for district heating networks due to their high heat demand density, potential geologically suitable geothermal sites are not always located within or close to large cities. At the same time, the economic utilizat...     »