scholarly journals Self-start manual for direct use applications of geothermal resources

1978 ◽  
Author(s):  
C.C. Christiansen
Keyword(s):  
Geothermal Resources ◽  
Direct Use

scholarly journals Direct Use of Geothermal Resources for Circular Food Production

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 497 ◽  
Author(s):  
Ragnheidur Thorarinsdottir ◽  
Runar Unnthorsson
Keyword(s):  
Value Chain ◽  
Production System ◽  
Food Production ◽  
System Optimization ◽  
Production Unit ◽  
Heat Extraction ◽  
Geothermal Resources ◽  
Commercial Unit ◽  
Recirculating Aquaculture Systems ◽  
Direct Use

The objectives of the work are to increase the direct use of geothermal resources for circular food production systems. The focus is on circular agricultural production processes: combining recirculating aquaculture systems and hydroponics into one system, including water treatment and waste recovery processes. The main outputs are vegetables, fish, fertilizers and potentially, algae and biogas. These outputs can generate revenue streams that can cover the costs of heat extraction while supporting viable businesses. The results and conclusions from a pilot case that was conducted in Iceland in recent years are presented, and the next steps are discussed. The pilot setup is now in the process of expansion to a semi-commercial production unit. However, there are still scientific, technical and commercial challenges to be solved. The scientific challenges are interdisciplinary and relate mainly to the optimization of the overall production system. Optimization involves creating good environmental conditions for each production unit while maintaining optimal oxygen, carbon dioxide, relevant pH and temperature levels and supplying all necessary nutrients. Additionally, accumulation of salts or other unwanted substances must be prevented. The primary technical challenges are to develop the circular food production system for optimized production while controlling the expenditure of energy, water, nutrients and manpower resources. Optimization also involves careful choices of species and the integration of new ideas into the value chain, both of which increase the synergy between the different components of the system. Furthermore, energy efficiency needs to be improved through using excess heat for other parts of the system and developing enhanced heating and cooling cycles. The aim is to transform the semi-commercial unit into a showcase model for solving commercial challenges while presenting a feasible business model for installing and operating a geothermal well for circular food production, making the most use of all available resources, securing optimum production conditions and minimizing waste.

scholarly journals New methods of geothermal potential assessment in the Pannonian basin

2019 ◽  
Vol 98 ◽  
Author(s):  
Annamária Nádor ◽  
László Sebess-Zilahi ◽  
Ágnes Rotár-Szalkai ◽  
Ágnes Gulyás ◽  
Tamara Markovic
Keyword(s):  
Pannonian Basin ◽  
Pore Space ◽  
Heat Content ◽  
Geothermal Resources ◽  
Geothermal Potential ◽  
Technical Potential ◽  
Long Time ◽  
Geothermal Model ◽  
Bounding Surfaces ◽  
Direct Use

Abstract The Pannonian basin in Central Europe is well known for its rich geothermal resources. Although geothermal energy has been utilised, mainly for direct use purposes, for a long time, there are still a lot of untapped resources. This paper presents novel methods for outlining and assessing the theoretical and technical potential of partly still unknown geothermal reservoirs, based on a case study from the Dráva basin, one of the sub-basins of the Pannonian basin along the Hungarian–Croatian border. The presented methods include reservoir delineation based on combining geological bounding surfaces of the Upper Pannonian basin-fill units with a set of isotherms deriving from a conductive geothermal model. The geothermal potential of each identified reservoir was calculated by a Monte Carlo method, which was considered as being represented by the heat content of the fluids stored in the effective pore space (‘moveable fluid’). The results underline the great untapped geothermal potential of the Dráva basin, especially that of the reservoir storing thermal water of 50–75°C, which has the largest volume and the greatest stored heat content.

scholarly journals Introduction to this special section: Geothermal energy

2020 ◽  
Vol 39 (12) ◽  
pp. 855-856
Author(s):  
J. O. Kaven ◽  
D. C. Templeton ◽  
Arpita P. Bathija
Keyword(s):  
Geothermal Energy ◽  
Special Section ◽  
Renewable Resource ◽  
The United States ◽  
Geothermal Systems ◽  
Geothermal Resources ◽  
Elevated Pressures ◽  
Generation Capacity ◽  
Direct Use

Geothermal energy is a global renewable resource that has the potential to provide a significant portion of baseload energy in many regions. In the United States, it has the potential to provide 8.5% of the electric generation capacity by the middle of the century. In general, geothermal systems require heat, permeability, and water to be viable for energy generation. However, with current technologies, only heat is strictly necessary in a native system. Engineered geothermal systems (EGS) introduce water into the subsurface at elevated pressures and reduced temperatures and enhance permeability through hydraulic and/or shear fracturing. Additionally, although moderate- to high-temperature resources currently dominate geothermal energy production, low-temperature resources have been utilized for direct-use cases. When well balanced and maintained, geothermal resources can produce significant amounts of heat and achieve long-term sustainability on the order of an estimated tens to hundreds of years.

scholarly journals Economic and fault stability analysis of geothermal field development in direct-use hydrothermal reservoirs

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Caroline Zaal ◽  
Alexandros Daniilidis ◽  
Femke C. Vossepoel
Keyword(s):  
Large Scale ◽  
Net Present Value ◽  
Spatial Density ◽  
Geothermal Systems ◽  
Geothermal Resources ◽  
Field Development ◽  
Fault Stability ◽  
Economic Output ◽  
Fault Permeability ◽  
Direct Use

AbstractThe installed capacity of geothermal systems for direct use of heat is increasing worldwide. As their number and density is increasing, the their interaction with subsurface faults becomes more important as they could lead to safety risks from induced seismicity. Assessment and management of such risks is essential for the further development and extension of geothermal energy for heating. At the same time, the economic output of geothermal systems can be marginal and is hence often supported by subsidy schemes. A combined assessment of fault stability and economic output could help operators to balance economic and safety aspects, but this is currently not common practice. In this study we present a methodology to assess field development plans based on fault stability and Net Present Value (NPV) using reservoir simulations of a fluvial, heterogeneous sandstone representative of the majority of direct-use Dutch geothermal systems. We find that the highest friction coefficient leading to exceedance of the Mohr–Coulomb failure criteria in this sandstone is 0.17; such values could be encountered in clay-rich fault gouges. Similar or lower fault permeability compared to the reservoir results in no changes and an increase respectively of both NPV and fault stability with larger Fault-to-Well Distance (FWD). Fault permeability higher than the reservoir permeability results in a minor increase in NPV with smaller FWD. Our results demonstrate that a combined analysis of thermal, hydraulic, mechanical and economic assessment supports a responsible and viable development of geothermal resources at a large scale. The importance of a high spatial density of supporting stress data will be essential for a better understanding and quantification of economic and fault stability effects of geothermal operations.

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