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Although the Acque Albule Basin has been studied since the middle of the 19th century, a comprehensive geologic conceptual model of the area has not yet been developed. The natural setting has been heavily modified by anthropic activities. Rapid evolution during the last 25 years has caused many interferences, which have led to a drastic increase of the hazards and linked risks, mainly related to water resource overexploitation and subsidence.
The implementation of an exhaustive framework has become mandatory for environmental and management purposes. Starting from a critical review of previous studies, hydrogeologic and hydrogeochemical surveys and related numerical modeling have been carried out in order to achieve a quantitative understanding of the active phenomena and processes.
Several hydrogeologic issues have been addressed concerning aquifer recharge areas and the different flowpaths of groundwater in respect to their division into a shallow and a deep circuit. Account has been taken of the groundwater chemistry as a function of water—rock interactions and mixing processes with uprising fluids. Different scenarios of groundwater flow in the Acque Albule aquifer have been built, using previously available piezometric measurements and the hydrodynamic parameters determined by in situ tests. These results led to the formulation of an updated hydrogeologic conceptual model to be further implemented, in which past, present and future anthropic instances and the potential of natural resources of the area have been included and taken into account. A sound conceptual model must rely on the design and development of a logical geo-database in which information is stored, updated and processed. This operational framework can result in a useful tool for land management, surveys planning and design, hazard and risk evaluation, identification of best practices and economic development of the area.
The general characterization of the Hungarian Szentes geothermal field is presented based on the review of previous research and is supplemented with the analysis of well hydraulic tests. Forty thermal wells were included in the study area, producing mainly from Upper Pannonian sandstone reservoirs. The intensive and long-term production of thermal water reservoirs without reinjection resulted in significant reservoir pressure decrease from natural conditions. By means of deep-well pressure build-up curves, deep-well capacity curves and surface pressure curves the reservoir condition changes were described in the last half century.
Europe’s largest thermal water system can be found in the capital of Hungary. The springs and wells that supply the famous baths of Budapest discharge mainly from a regional Triassic carbonate rock aquifer system. The springs have mostly been substituted by wells; only a few natural springs are known today, most of which are drained unused into the Danube.
In this study, first the heat potential of these unutilized spring waters in the three natural discharge areas was assessed. Secondly, the heat potential of used thermal waters of three baths was calculated. At the springs discharge and temperature measurements were carried out. In the case of the baths, water management data were evaluated. At the Boltív Spring at the foot of Rózsadomb, the heat potential calculation shows that cooling the spring water to 5 °C would provide 6 MWth thermal capacity, providing a stable energy source for heat pumps. From the overflowing water of the springs of Rudas Bath at the foot of Gellért Hill, a total of 107 kWth heat could be utilized when cooling it to 5 °C, possibly by heat pump system. However, the heat potential of the Bründl Spring is not sufficient for geothermal utilization, mainly due to lack of end users in the vicinity of the spring. Together with the wastewater of the thermal baths, the effluent springs and wastewaters of pools carry a total of 25 MWth waste heat, which is a considerable amount compared to the needs of a public institution. The importance of this study is in the assessment of such potential heat sources (unused lukewarm and thermal springs, wastewater of spa pools) which are present either naturally or artificially, and do not require further thermal water production for heating purposes.
The heat content of shallow or deep aquifers can be used for space heating. Two innovative systems are described below in detail: a geothermal heat pump system based on a single well in China (= shallow), and a cascading use of tunnel waters (= deep) in Switzerland. The “Single Well System” (HYY SWS) was invented and developed by Beijing Ever Source Science & Technology Development Co., Ltd (HYY) to provide buildings with heating and cooling as well as with domestic hot water. The powerful system operates at about 500 kWth capacity. Unlike traditional groundwater heat pump systems, in which two wells are used (one for pumping groundwater out and the other to dispose of cooled water), the HYY SWS uses only one, specially designed well for production and reinjection. A borehole with a depth of about 70–80 m and a diameter of 0.5 m is drilled for HYY Single Well Systems. The necessary local geologic site condition is to have a shallow aquifer with a hydraulic conductivity of 10−3 m/sec or higher. Many such systems operate now in China, several of which, for instance, serve the 2008 Summer Olympic Facilities in Beijing. Switzerland has, in its mountainous parts, hundreds of deep tunnels. Tunnels drain the rock overburden and, depending on its thickness, water temperatures up to 50 °C can be encountered and utilized. The most straightforward and cheapest form of tunnel heat usage is to collect and transport inflowing waters via ducts to the portals, with as little temperature drop as possible. The thermal power depends on flow rate and temperature. At or near the portals the heat content of the waters can be used for various applications. When the temperature level of the tunnel water outflows is too low for direct applications (e.g. for district heating), heat pumps are employed. From Switzerland a whole suite of uses can be reported: space heating, greenhouses, balneology and wellness, fish farming. At the northern portal of the 35 km long Loetschberg base tunnel at Frutigen, the tunnel water is used subsequently (“cascading”) for space heating, greenhouse, and fish farming (incl. caviar production).
Our research team has developed a new well completion and rework technology involving lasers. The system is made up of a high-power laser generator and a custom-designed directional laser drilling head. The laser head is attached to a coiled tubing unit to maximize production and to carry out special downhole tasks. In this phase of the development effort, laser technology is particularly well suited to cost-efficiently drill short laterals from existing wells in a single work phase, drilling through the casing and cement as well as the formation. The technology, which is an extended perforation solution, enables a more intensive interaction with the downhole environment and supports cutting edge subsurface engineering scenarios such as barite removal. Laser-induced heat treatment appears to be a suitable alternative to effectively remove the almost immovable deposits and scales from thermal water-well pipes.
Budapest is famous for its thermal springs and spas and outstanding thermal water resources. In the 21st century renewable energy utilization — including the use of geothermal energy — became the focus of interest. Improving the use of the different forms of geothermal energy requires the assessment of their possibilities. The potential for deep geothermal doublet systems for direct heating in Budapest was evaluated based on the temperature conditions, the depth and reconnaissance of the carbonate reservoir. NW Buda is not appropriate for thermal water exploration. SW and SE Budapest have better temperature conditions but the lithology of the reservoir is uncertain. Beneath Pest the thermal water is well exploitable. It is obvious from the map of the region that the area is promising; however, due to the hydraulic continuity of the system, reinjection is desirable. Considering the reliability of the employed data the geothermal potential map is suitable only for general orientation and guidance.
The geothermal potential map for Groundwater-sourced Heat Pump Systems (GHPS; scale = 1:40,000) was assembled by evaluating the thickness and appearance of the gravel strata and water table, complemented by the sulfate content as an aggressive component of groundwater. The original geothermal potential map series can be used for the evaluation of potential sites in Budapest. It can be concluded that the Buda side of the Danube River is almost entirely unsuitable for shallow groundwater-based heat pump installations. The only areas under consideration are Óbuda and the riverbanks. On the Pest side, there is no gravel in the central part; the largest areas close to the river and in the immediate surroundings are uncertain, with patches of suitable and possible categories. The southern and eastern area of Pest is the most prospective for GHPS installation. The potential maps only consider natural parameters; however, installation may be strongly influenced by the urbanization and the city environment.
The Institute of Environmental Management at the University of Miskolc, as a major Hungarian research entity in groundwater management, is dedicated to finding solutions to regional issues of global sustainable water resource management challenges, thus further developing its scope of groundwater management competence. WELLaHEAD is an EU-funded fundamental research program coordinated by the faculty members of the institute, covering a broad spectrum of relevant groundwater related research topics based on Northern Hungarian test sites. The research concept is described in the detailed Research Plan of the project, and after 14 project months some of intermediate results can be presented from three research modules.
The Triassic karstic aquifer is the system with the greatest potential for the utilization of thermal waters in Serbia. As an integral part of the Dinaric tectonic unit, the Triassic aquifer extends widely over the western part of the Serbian territory and is characterized by cold waters. In contrast, the same but confined type of aquifer overlain by thick Tertiary sediments in the Pannonian Basin has significant geothermal potential. The major potential for tapping geothermal flow is in the southern and southwestern parts of the Pannonian Basin (Srem) and in the adjacent areas of Mačva and Semberija in the Sava tectonic graben. In these areas the Triassic karstic aquifer has been tapped by several boreholes with depths ranging from 400 m to 2400 m. The temperature of the hottest water exceeds 75 °C, while maximal discharge is 40 l/s.
Although the prospect of wider utilization of geothermal energy undoubtedly exists, some Serbian national plans count on a limited contribution of geothermal energy in renewable energy sources of only 4%. This is probably due to the low level of current utilization, and the inefficient use of even some highly productive wells with a high water temperature, such as those drilled in the most prosperous Mačva region.
