Thermal waters of central Poland: a case study from Mogilno–Łódź Trough, Poland

Abstract

AbstractThermal waters in Poland occur in several different geothermal regions, but the best parameters for their effective utilisation are connected i.a. with the area of Polish Lowlands. One of the most prospective areas in the central part of Polish Lowlands for managing geothermal waters for various purposes is the area of Mogilno–Łódź Trough. There are currently 2 operating geothermal heating plants and several others in various stages of development. In this area, water with a temperature of 97.5 °C has been documented. The aim of this article is to determine and visualise the potential of geothermal waters of the central Poland (Mogilno–Łódź Trough) by providing the most important, potential geothermal water parameters. It is done by providing maps of potential temperature, mineralization, water outflow capacity, thermal power and physicochemical analysis (mineralization, waters type). The two most prospective geothermal reservoirs—Lower Jurassic and Lower Cretaceous—were analysed. The results of the studies indicate that this area is characterised by very favourable hydrogeological conditions. Geothermal energy utilisation should be connected with Lower Jurassic and Lower Cretaceous reservoirs, but it should be emphasised that a larger energy potential relates to waters from Lower Jurassic reservoir; however, they are characterised by high water mineralisation (up to 170 g/L). Waters of Lower Cretaceous reservoir are characterised by not only lower mineralisation (up to 100 g/L), but also lower temperature (max. 75 °C). The highest temperatures in the Lower Jurassic are recorded in the axial part of the Trough, where, locally, they exceed in the top of formation 100 °C. On the other hand, in edge Trough zones, water temperatures are 30–40 °C. The actual geothermal potential of the area is much higher than currently used. For example, potential discharge of wells is to over 400 m3/h in the Lower Cretaceous and up to over 500 m3/h in the Lower Jurassic.