a b s t r a c tThe article presents the results of modelling geothermal conditions in the Lower Triassic sedimentary formations of the Polish Lowland area (central Poland) and an electricity production model for a prospective EGS (Enhanced Geothermal System) installation situated in that area. On the basis of comprehensive analyses, this area has been selected as optimal for EGS plants operating in sedimentary complexes in the Polish Lowland. Numerical modelling was conducted using TOUGH2 code and served to evaluate the energy performance of the prospective EGS plant operating in the area. Modelling results indicate that the energy performance of the EGS plant is strongly dependent on the volume and permeability of the artificially fractured zone and its net power is dependent on the power consumed by the circulating pumps that stimulate the flow. For the top layer of the Buntsandstein formation at a depth of ca. 5500 m and temperature of ca. 170 C, the modelled net power of an EGS plant operating in the area ranged from 2 to 3 MW for a circulation of 200 m 3 /h, and at 100 m 3 /h it ranged from 1.3 to 1.6 MW depending on the permeability and volume of the fractured zone used for the circulation in question.

The main objective of this study was to develop a spatial temperature distribution of the Karkonosze Pluton to indicate optimum locations for HDR systems at drillable depth. HDR geothermal technology makes it possible to extract heat from the Earth in areas where no hydrogeothermal resources are present. To produce electricity in a binary cycle, system temperatures of > 100°C are usually required. In this paper, the authors have analysed the potential opportunities for applying HDR technology in the area of the Karkonosze Pluton, which is regarded as an optimum location for the application of the HDR concept (due to the potential for stimulation offered by the mechanical properties of the granites, radiogenic heat production, modern tectonic activity, and the thickness of the pluton). The model used in the analysis, which takes into account a hypothetical assessment of the manner and paths of fluid migration within the pluton, provides an insight into the spatial distribution of subsurface temperatures. It thus allows the location of relatively shallow high-temperature zones, which are optimal for the efficient application of HDR technology, to be identified. With respect to this technology, the Szklarska Poręba area and the NE part of the pluton seem to be better targets than the Cieplice central area, where the model indicated much lower temperatures (e.g. at a depth of 5,000 m, estimated temperatures in the vicinity of Szklarska Poręba were about 185°C and in the vicinity of Cieplice they were about 140°C).Keywords: HDR technology, Karkonosze Pluton -Poland, structural and thermal model Celem badań było opracowanie przestrzennego rozkładu temperatur plutonu Karkonoszy dla wskazania optymalnej lokalizacji dla systemu HDR na głębokościach osiągalnych wierceniami.Geotermalna technologia HDR umożliwia wykorzystanie ciepła wnętrza Ziemi na obszarach pozbawionych płynów termalnych głównie a aspekcie produkcji energii elektrycznej w systemach binarnych. Dla efektywnej pracy takich systemów wymagana jest temperatura górotworu powyżej 100°C. W artykule autorzy analizowali potencjalną możliwość zastosowania technologii HDR na obszarze plutonu Karkonoszy, który potraktowano jako optymalny dla zastosowania systemu HDR -głównie wskutek mechanicznej podatności granitów na procesy sztucznego szczelinowania, wysoką produkcję ciepła radiogenicznego, współczesną aktywność tektoniczną oraz znaczną miąższość plutonu. Prezentowany, hipotetyczny model strukturalno-termiczny uwzględniający sposób i drogi migrujących płynów pokazuje przestrzenny rozkład wgłębnych temperatur w obrębie plutonu. Umożliwia to lokalizację stref wysokich temperatur położonych względnie płytko, a zatem optymalnych dla efektywnego zastosowania technologii HDR. W tym kontekście, strefa plutonu w rejonie Szklarskiej Poręby oraz jego część NE przedstawiają się korzystniej niż strefa centralna w rejonie Cieplic, gdzie przeprowadzone modelowanie wskazuje temperatury znacznie niższe (np. w strefie Szklarskiej Poręby na głębokości 5000 m temperatury około 185°C n...

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.

In view of the disastrous air pollution in the Silesian–Kraków region, reducing emissions from the combustion of conventional fuels is a particularly important issue. Geothermal energy is among the clean and renewable sources of heat that could be used to this end, for instance for recreation or space heating purposes. However, its use in the region is limited, mainly due to insufficient knowledge of the characteristics of the geothermal complexes present. Mesozoic complexes in the region have much smaller energy resources compared to the Polish Lowlands or Podhale, but Paleozoic ones, mainly the Lower Carboniferous and Devonian, offer realistic prospects for energy extraction. The aim of this study was to identify geothermal conditions within the Lower Carboniferous–Devonian complex, primarily in terms of using the waters present there for space heating purposes. The prospective zones identified and indicated during the research are only forecasts, and their actual utility can only be confirmed after new wells have been drilled to verify the actual conditions.

The agriculture and related sectors present one of the most prospective areas for geothermal energy applications. In many countries they have already been introduced, and new investments in this sector have been also observed. Also Poland has the appropriate resources’ potential – in a wide range of temperatures, for different crops, as well as in the types of applications related to agriculture. The use of this green energy can contribute to sustainable development of agriculture.To achieve this when planning and designing geothermal installations for agriculture, they should be considered from the energy and agricultural points of view, as well as appropriate locations for them shall be selected so that they would be harmoniously incorporated, among others, into existing systems of valuable natural areas (which already play various important functions in the natural environment) and would not interfere with other underground resources of strategic economic importance.The main aspects of such an approach to the sustainable development of the geothermal energy applications in agriculture and related sectors in Poland, as well as natural circumstances, are presented in this article. Also included are basic energy parameters (based on the results of calculations) and technical and economic parameters for greenhouse facilities in one of the selected prospective locations in the Polish Lowlands, which could be supplied by local geothermal resources, contributing to sustainable development of agriculture.