Barbara Tomaszewska

Dynamics of clogging processes in injection wells used to pump highly mineralized thermal waters into the sandstone structures lying under the polish lowlands

Abstract When identifying the conditions required for the sustainable and long-term exploitation of geothermal resources it is very important to assess the dynamics of processes linked to the formation, migration and deposition of particles in geothermal systems. Such particles often cause clogging and damage to the boreholes and source reservoirs. Solid particles: products of corrosion processes, secondary precipitation from geothermal water or particles from the rock formations holding the source reservoir, may settle in the surface installations and lead to clogging of the injection wells. The paper proposes a mathematical model for changes in the absorbance index and the water injection pressure required over time. This was determined from the operating conditions for a model system consisting of a doublet of geothermal wells (extraction and injection well) and using the water occurring in Liassic sandstone structures in the Polish Lowland. Calculations were based on real data and conditions found in the Skierniewice GT-2 source reservoir intake. The main product of secondary mineral precipitation is calcium carbonate in the form of aragonite and calcite. It has been demonstrated that clogging of the active zone causes a particularly high surge in injection pressure during the fi rst 24 hours of pumping. In subsequent hours, pressure increases are close to linear and gradually grow to a level of ~2.2 MPa after 120 hours. The absorbance index decreases at a particularly fast rate during the fi rst six hours (Figure 4). Over the period of time analysed, its value decreases from over 42 to approximately 18 m3/h/MPa after 120 hours from initiation of the injection. These estimated results have been confi rmed in practice by real-life investigation of an injection well. The absorbance index recorded during the hydrodynamic tests decreased to approximately 20 m3/h/MPa after 120 hours.

APPLICATION OF A HYBRID UF-RO PROCESS TO GEOTHERMAL WATER DESALINATION. CONCENTRATE DISPOSAL AND COST ANALYSIS

Abstract M embrane-based water desalination processes and hybrid technologies are often considered as a technologically and economically viable alternative for desalination of geothermal waters. This has been confirmed by the results of pilot studies concerning the UF-RO desalination of geothermal waters extracted from various geological structures in Poland. The assessment of the feasibility of implementing the water desalination process analysed on an industrial scale is largely dependent on the method and possibility of disposing or utilising the concentrate. The analyses conducted in this respect have demonstrated that it is possible to use the solution obtained as a balneological product owing to its elevated metasilicic acid, fluorides and iodides ions content. Due to environmental considerations, injecting the concentrate back into the formation is the preferable solution. The energy efficiency and economic analysis conducted demonstrated that the cost effectiveness of implementing the UF-RO process in a geothermal system on an industrial scale largely depends on the factors related to its operation, including without limitation the amount of geothermal water extracted, water salinity, the absorption parameters of the wells used to inject water back into the formation, the scale of problems related to the disposal of cooled water, local demand for drinking and household water, etc. The decrease in the pressure required to inject water into the formation as well as the reduction in the stream of the water injected are among the key cost-effectiveness factors. Ensuring favourable desalinated water sale terms (price/quantity) is also a very important consideration owing to the electrical power required to conduct the UF-RO process.

Modelling geothermal conditions in part of the Szczecin Trough – the Chociwel area

Abstract The Chociwel region is part of the Szczecin Trough and constitutes the northeastern segment of the extended Szczecin-Gorzów Synclinorium. Lower Jurassic reservoirs of high permeability of up to 1145 mD can discharge geothermal waters with a rate exceeding 250 m3/h and temperatures reach over 90°C in the lowermost part of the reservoirs. These conditions provide an opportunity to generate electricity from heat accumulated in geothermal waters using binary ORC (Organic Rankine Cycle) systems. A numerical model of the natural state and exploitation conditions was created for the Chociwel area with the use of TOUGH2 geothermal simulator (i.e., integral finite-difference method). An analysis of geological and hydrogeothermal data indicates that the best conditions are found to the southeast of the town of Chociwel, where the bottom part of the reservoir reaches 3 km below ground. This would require drilling two new wells, namely one production and one injection. Simulated production with a flow rate of 275 m3/h, a temperature of 89°C at the wellhead, 30°C injection temperature and wells being 1.2 km separated from each other leads to a small temperature drop and moderate requirements for pumping power over a 50 years’ time span. The ORC binary system can produce at maximum 592.5 kW gross power with the R227ea found as the most suitable working fluid. Geothermal brine leaving the ORC system with a temperature c. 53°C can be used for other purposes, namely mushroom growing, balneology, swimming pools, soil warming, de-icing, fish farming and for heat pumps.

Numerical modelling in research on geothermal systems

Abstract Nowadays, numerical modelling is a common tool for supporting the research of geothermal systems. Due to the development of computer sciences and access to software dedicated to numerical modelling of hydrogeological processes this is possible. Research can schematise hydrogeological conditions and simulate the work of geothermal systems and thermal water intakes. Research creates numerical models of geothermal systems at the regional and local scale for simulating work of specific thermal waters for example. In connection with the economic development of the use of thermal waters in Poland there are many research projects where numerical modelling occurs as a primary tool. This paper provides an overview of research issues where the solution to the problem was found by using computer applications and numerical simulators.

The review of Polish formal and legal aspects related to hydropower plants

In recent years, dynamic growth of expenditure on environmental protection has been observed in European Union (EU) countries (Tsireme et al. 2012). Access to EU funds has allowed significant resources for the financing of investment and ecological activities to accumulate in some countries (Kulczycka and Smol 2016). Renewable power engineering sector investments are recognised, by virtue of the European Parliament and Council Directive 2009/28/EC of 23 April 2009 on the promotion of the use of energy from renewable sources as important sources of energy, supported due to the care about the environment. Thus, the benefits from execution of such investments are highly valued in both regional and global scale, especially in the aspect of climatic changes and progressing pollution of the environment (Mennicken et al. 2016). To confirm the priority of sources of energy recognised as renewable and friendly to the environment, the directive imposes the obligation of generating and managing resources of renewable source energy, thus defining the objectives for the member countries, including Poland—at 15% of the gross final consumption of energy by 2020. Research addressing the development of the use of hydropower engineering and its improvement (Kougias et al. 2016a, b) and improvement of conditions of the functioning of the facilities is conducive for new projects executed in many parts of the world (Chang et al. 2010) and Europe (Bodis et al. 2014, Pacesila et al. 2016). Consumption of energy generated in hydropower plants constitutes an important share in the final consumption of gross energy. At the end of 2011, over 160 countries had hydropower resource capacity, with a total capacity of 936 GW across 11,000 hydropower stations. The leading generating countries were China (61.4 Mtoe per year), Canada (29.9 Mtoe per year), Brazil (36.9 Mtoe per year) and the USA (23 Mtoe per year), respectively, although it is worth noting that Norway and India both have significant hydropower generation, particularly relative to their size and total electricity supply (World Energy Council 2016). In Poland, installed power in hydropower plants in 2015 was estimated at 977,676 MW (URE 2016). Figures 1 and 2 present the data on installed power in Polish hydropower plants and forecasts resulting from EU obligations. The legislation of the countries of the EU provides the basic definitions in the directives then determine the community attitude to many aspects, including to the use of renewable sources of energy. Unification of terms in the pursuit to achieve the ultimate objectives, defined in the basic community document (the said Directive 2009/28/EC), has the key significance and is focused on achieving the goal that is often commonly called B3 × 20^. The definition of Brenewable energy source^ follows which has been evolving in the successive Bpower^ directives (Table 1). Communicated by: Philippe Garrigues

Evaluation of the Possibility of Use Geothermal Energy Micropiles TITAN 73/53 to Obtain Low-Temperature Heat Energy Accumulated in the Near-Surface Layers of the Ground in Poland Area

Increasing demand in the usage of low-temperature energy sources such as atmospheric air, ground, groundwater or wastewater, which are freely available in the environment, lead to seek new methods and technologies to obtain them. One of these are for example geothermal energy piles (GEP), foundation piles inside which a vertical exchanger is placed to exploit low-temperature geothermal energy. They gained growing popularity over past few years, because of modern assembly technology which allows to make them in any conditions during one technological process. The aim of the work was to estimate the possibility of use geothermal energy micropiles TITAN 73/53 to obtain low-enthalpy heat energy from near-surface layers of the ground in Poland area. Assessment was carried out based on Map of Geological-Engineering of Poland on a scale of 1:500,000, enriched with information gained from literature data and from TITAN Polska Company. Conducted analysis has shown that geothermal energy micropiles TITAN 73/53 in the most parts of the country can be used as very promising and cost-effective technology for more efficient, even 50% more than conventional, acquisition of relatively large amounts of heat energy accumulated in shallow layers of ground in Poland area.

Prospects of geothermal water Use in cultivation of Spirulina

Abstract Spirulina has been studied due to its commercial importance as a source of essential amino acids, protein, vitamins, fatty acids etc. Most of the culture systems in use today are open ponds. The new approach proposed in this paper is to use the geothermal water as a medium for microalgae cultivation. Poland has beneficial conditions for wide geothermal use, as one of the environmentally friendly and sustainable renewable energy sources. In the planned research, geothermal water could be used to prepare microalgal culture medium, to heat greenhouses with bioreactors used for the growth of Spirulina, to dry the obtained biomass, as well as to heat the ground in foil tunnels. Using geothermal water gives the possibility to produce algae in open ponds covered with greenhouses and to cultivate plants during winter. The obtained algae can be used for the production of algal bio-products (e.g. homogenates), having the potential application in plant cultivation. Graphical Abstract

The Energy Efficiency in a Commune. The Formal and Legal Requirements with Examples of a Good Practice

The energy efficiency together with the utilization of renewable energy resources are considered to be crucial parts of a transition to the low-carbon economy. Their development can involve various administrative levels, nevertheless, the tremendous potential is assigned to a commune. Thus, the paper presents the most important formal and legal regulations that have an influence on the improvement of the energy efficiency, considering mainly obligations arising directly from the Energy Law and the Energy Efficiency Act. Moreover, the importance of the effective energy management in a commune is strongly emphasized, as the key for the low-carbon and resource-efficient economy. In the instance of the development of the energy efficient economy, many benefits are pointed out, and in case of the collaboration between neighboring communes, they are often multiplied at that. The particular examples of projects that have been realized in Polish communes of Niepolomice (the installation of renewable energy systems for public and private buildings) and Charasznica (the modernization of the street lighting), together with the indication of costs and profits relevant to the investment in the energy efficiency, as well as the environmental and socio-economic aspects, are also presented.

Selected technical aspects of well construction for geothermal energy utilization in Poland

Abstract Geothermal resources have been used in Poland since the 90s of the last century. Since then, several geothermal heating plants, recreation and balneological centers have been operated. Accessing geothermal resources is possible due to deep boreholes that are either brand-new wells or old but revitalized petroleum and/or exploratory wells. In this case, the construction of production and injection wells is of significant importance. The utilization of deep geothermal energy resources is strongly dependent on the binding domestic law regulations – primarily in case of acquiring the concession enabling an execution of geological and drilling works, and subsequently a proper exploitation. The paper presents the current state of development of the geothermal energy sector in Poland, indicating examples of exploitation systems based on deep boreholes. Furthermore, the constructions of existing wells are discussed extensively. The existing examples of old but reconstructed wells in Poland, are characterized. The importance of national law and its influence on the development of a geothermal investment is highlighted, as well.

Solar, wind and geothermal energy applications in agriculture: back to the future?

The agri-food chain consumes about one third of the world’s energy production with about 12% for crop production and nearly 80% for processing, distribution, retail, preparation and cooking (Fig. 1.1) (FAO, 2011b). The agri-food chain also accounts for 80–90% of total global freshwater use (Hoff, 2011) where 70% is for irrigation alone. Additionally, on a global scale, freshwater production consumes nearly 15% of the entire energy production (IEA, 2012). It can therefore be argued that making agriculture and the agri-food supply chain independent from fossil fuel use has huge potential to contribute to global food security and climate protection not only for the next decades, but also for the coming century. Provision of secure, accessible and environmentally sustainable supplies of water, energy and food must thus be a priority. One of the major objectives of theworld’s scientists, farmers, decision-makers and industrialists is to overcome the present dependence on fossil fuels in the agri-food sector. This dependency increases the volatility of food prices and affects economic access to sustenance. For example, Figure 1.2 shows the close interrelationship between the crude oil price index and the cereals price index. An increasing energy demand for cultivation is particularly important in regions with expanding irrigated agriculture using pumped water. This translates to a food-related risk to energy security. The development and commercialization of renewable energy sources such as solar, wind and geothermal provides great potential to reduce costs in the agri-food sector. For instance, in addition to power generation, the main uses of geothermal waters are for space heating, district heating, spas balneology, aquaculture and greenhouse heating (Lund and Boyd, 2015). However, much work remains to be done to make better use of renewable energy in the agri-food sector. The aim of this introductory chapter is to critically review recent developments in solar, wind and geothermal energy applications in agriculture and the agri-food sector such as processing, distribution, retail, preparation and cooking.