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The geothermal energy sector continues to develop dynamically in the world. Within this work, preliminary feasibilities of different geothermal applications were presented for the Lower Cretaceous formations for wider geothermal uses' development in the Mogilno-Lodz trough, Central Poland. The Lower Cretaceous formations are one of the most prospective geothermal reservoirs in Central Poland. Geothermal waters that occur within them are mostly of Na-Cl type and contain specific elements like I, Br or Fe. These are low-temperature geothermal resources together with highly variable mineralization, from 0.4 to even more than 90 g/L. A simple estimation procedure for hydrogeological information, such as water and thermal conditions of the reservoir obtained from an archival chemical analysis and borehole temperature loggings was developed. The potential for geothermal applications was estimated for three zones of the Mogilno-Lodz trough. Possibilities of conjunctive geothermal applications, such as space heating, balneotherapy and balneorecreation, mineral extraction, electricity production in binary systems and aquifer thermal energy storage were examined for the Lower Cretaceous formations. Keywords Geothermal waters • The Lower Cretaceous aquifer • Low-temperature geothermal resources • Geothermal water applications • Renewable energy sources • PolandThis article is part of the special issue on Sustainable Resource Management: Aqua.

Although geothermal resources are practically independent of climate factors, those factors significantly condition the potential use of the Earth’s natural heat resources. Unlike all the other factors limiting or facilitating the use of geothermal heat (like receivers’ temperature expectation, financial issues or local regulations), climate factors remain immovable. Thus, climate remains the main factor influencing the effective use of geothermal resources. Volumes of sold energy, typical capacity factors and rapid changes in heat demand may all influence the financial and technological performance of an investment. In the current paper, climate factors are translated into heat demand based on historical data (meteorological and district heating logs) by means of a dedicated artificial neural network, and analysed in terms of possible constraints and facilitators that might affect the effective use of geothermal energy. The results of ANN simulation indicate that average and typical operation is expected without any turbulences, yet about 10% of operating hours may require additional technical measures, like peak source support, smart management and buffers in order to limit pumping ramp rate. With appropriate dimensioning and exploitation, capacity factors as high as 60% are available, proving the potential for financially and environmentally effective use of geothermal resources.

Agriculture is among the most promising applications of geothermal energy, and Poland has conditions to develop geothermal use in this sector. Suitable locations for agricultural geothermal installations shall be selected during the planning stage. To support the selection process, the authors chosed and analyzed thematic maps and other information on basic natural conditions for agriculture in Poland, potential conflicts between the operation of possible geothermal agricultural installations and other important functions of the natural environment, valuable natural areas and protection systems, elements of the current agricultural economy, etc. The authors combined them with the spatial distribution of geothermal reservoir parameters suitable for their agricultural applications using CorelDRAW X7 software. As a result, the regions with prospective geothermal applications in a sustainable agriculture can be identified, while maintaining the existing natural functions of the area. An example is given of the energetic, technical and economic calculations for agricultural greenhouses which can be supplied by geothermal resources in an area with existing natural functions, and a relevant study case is presented. The novel approach described in this paper may serve as an example in other countries of agricultural development with the use of geothermal resources.