Geoelectric Research Articles

Analytical study of integrating downhole thermoelectric power generation with a coaxial borehole heat exchanger in geothermal wells

Geothermal power generation employing Organic Rankine Cycle (ORC) technology is a widely acknowledged and conventional approach for harnessing geothermal energy. In an innovative advancement, we propose a novel design integrating downhole thermoelectric power generation with a coaxial borehole heat exchanger. This design aims to enhance the efficiency and sustainability of geothermal energy utilization. In this innovative design, the geothermal well is divided into two distinct sections: a power generation section and a heat exchanging section, achieved through the implementation of a packer positioned from the uppermost part of the targeted zone. The process involves the injection of cold fluid downhole via an insulated pipe. Subsequently, a portion of the injected fluid is directed to flow in reverse within the casing-tubing annulus above the packer, while another portion circulates into the casing-tubing annulus below the packer before ascending through the tubing. This dual flow mechanism establishes distinct cold and hot sources for the thermoelectric generator, a key feature facilitated by this innovative design. Analytical models detailing of downhole temperature distribution for thermoelectric power have been meticulously developed. A comprehensive case study, focusing on a geothermal well with 3000 m length of power generation section and 500 m heat exchanging section, has been conducted. The results indicate that a significant generating capacity could be achieved with a higher wellhead temperature, and the payback period under different carbon tax scenarios is about 6–8 year. Furthermore, the effects of injection rate, fluid diversion ratio, and casing-tubing configuration on power performance and thermal-electricity efficiency are also discussed. This method not only enables the concurrent harvesting of geothermal energy and power generation but also operates consistently throughout the year. The results thus emphasize the viability and economic feasibility of the proposed approach.

Evaluation of the energy performance of a shallow geothermal facility through a second‐order cone programming

AbstractEnergy consumption and operational cost are two decision‐making factors which evaluate the feasibility of any energy system. Whether a thermal unit is efficiently working or not depends on the state properties of the thermodynamic system. Therefore, operational research on a geothermal site was performed. Most research pivots around the basic energy conservation equation to determine the parameters. However, finding the parameters does not serve the purpose of an investor. Investment of capital in any project depends on the return and feasibility of the task performed under the project. In the same direction, this article focuses on the optimisation of the performance of a shallow geothermal site in terms of energy and plant economics using the concept of a second‐order cone program (SOCP). The site was used to operate the hybrid heating, ventilation, and air conditioning unit (HVAC) installed in an academic building. The second‐order cone programming was considered to minimize the energy requirement and cost of energy generation during the winter season. It is to be noted that the solver‐based approach was considered to examine the unit. The optimized energy consumption of GSHP was 24.29 kW⋅h. The levelized cost of energy (LCOE/kW⋅h) derived from SOCP would vary from $ 0.38 to $ 0.58 for the shallow geothermal plant. The rate of return for air conditioning in the building through the geothermal plant would be 1.74%. The optimized upfront cost per m2 was estimated to be $ 1440.87.

Temporal Fusion Transformer and transfer learning techniques applied to predict steam enthalpy with limited data in geothermal power plants

Temporal Fusion Transformer and transfer learning techniques applied to predict steam enthalpy with limited data in geothermal power plants

A Comprehensive Analysis of Electric Vehicle Adoption, Environmental Impact and Future Prospects

Electric Vehicles (EVs) are rapidly transforming transportation, offering a cleaner and more sustainable alternative to gasoline-powered cars. This paper delves into the history of EVs, highlighting their rise and fall, followed by the current resurgence driven by environmental concerns and technological breakthroughs. Government support and regulations play a crucial role in promoting wider adoption. The analysis examines the current landscape of EVs, marked by a booming market, advancements in battery technology, expanding charging infrastructure, and a growing variety of vehicle models. However, challenges such as range anxiety, limited charging options, battery cost, and consumer awareness still need to be addressed. The paper emphasizes the significant environmental benefit of EVs – zero tailpipe emissions when charged with renewable energy sources. It compares the pollution generated by EVs and fuel-based vehicles, showcasing the environmental advantages of EVs. The exploration of renewable energy sources like solar, wind, hydro, and geothermal power provides sustainable solutions for EV charging, with a comparison highlighting the most effective options. The conclusion acknowledges the cost and accessibility hurdles but underscores the importance of government incentives and cost-effective models in accelerating EV adoption. By highlighting the environmental and economic benefits of EVs, the paper reinforces their potential to combat climate change and pave the way for a more sustainable future.

Self-Sustainability for green energy in megacities: A case Study of Shanghai towards Net-Zero Goal

China’s ambitious 2060 net-zero carbon emission goal places increasing pressure on megacities to transition towards green energy self-sustainability. This paper delves into the feasibility of this target using a case study of Shanghai, the largest city in the world’s highest emitting nation. In the study, both quantitative and qualitative evaluations involving literature review, ArcGIS, and approximation analysis were applied to calculate the total amount of electricity that local could generate and maximize for renewable energy in order to fulfill the percentage of Shanghai’s energy demand. Through discussing various renewable methods such as solar, wind, tidal, and geothermal power, it projects the city’s potential for renewable energy self-sufficiency from now to 2060. The outcome of this study aims to: (1) Evaluate the vicinity and feasibility of green energy self-sustainability in megacities, considering the trade-off between ideal scenarios and real-world limitations; (2) Determine the necessity and potential volume of imported electricity under different renewable energy scenarios for Shanghai; (3) Provide a practical reference for other cities to benchmark their own renewable energy infrastructure development and assess their progress towards net-zero emissions; (4) Identify existing gaps and challenges that need to be addressed to achieve green energy self-sustainability in large urban centers. By offering a detailed analysis of Shanghai’s renewable energy potential and its implications for China’s national target, this study is expected to contribute to the broader discourse on urban decarburization and paves the way for a greener future for megacities worldwide.

Modelling the solubility of gases in aqueous solutions with a focus on geothermal applications– assessment and benchmarking of two free software packages

The interactions between aqueous solutions, gases, and minerals dictate the extent of issues such as scaling, degassing, and corrosion, which have a major impact on the performance of a vast number of industrial applications (e.g., geothermal plants, oil and gas production facilities, natural gas storage in saline aquifers, flue gas scrubbing, carbon sequestration, etc.). Among the different software programs available for aqueous chemistry calculations, Phreeqc and Reaktoro were tested and validated against a wide dataset of gas solubility measurements. For the datasets considered, the two programs essentially led to the same outcome with only a few discrepancies observed. Yet, the agreement between the models and experimental data was greatly affected by the selected database. The models implemented in Phreeqc and Reaktoro were also compared with the experimental bubble point pressure of fluids sampled at several geothermal wells. The satisfactory performance of both Phreeqc and Reaktoro for describing different chemical systems at a wide range of pressures and temperatures showcases their versatility and practicality for assisting in the design and optimization of various processes relevant to the energy transition (e.g., geothermal exploitation, CO2/H2 transport and storage).

Comprehensive Environmental and Economic Assessment of Low-Carbon Energy Sources

The article presents the results of a study of various low-carbon energy sources based on a multi-criteria analysis for the purpose of a comprehensive environmental and economic assessment of the effectiveness of their use. The peculiarity of the study is that it analyzed both renewable energy sources and traditional fossil fuel based ones using innovative technologies for carbon dioxide capture and storage, as well as nuclear energy. The purpose of this work is to conduct a comprehensive assessment based on three criteria: normalized cost of electricity LCOE (Levelized Cost of Energy)/LEC (Levelized Energy Cost), specific value of carbon dioxide emissions and material intensity expressed in total MI (Material Input) numbers. The hypothesis of the study is as follows: the introduction of the criterion of material intensity in MI numbers into a comprehensive assessment will allow one to identify low-carbon energy sources with the greatest ecological and economic effect. As a result, it was found that in 2023, the global energy capacity of low-carbon energy sources reached 51.8%, but the share of energy produced by them is significantly lower, amounting to only 39.4%. The multi-criteria analysis made it possible to identify low-carbon energy sources that, at the lowest cost, provide the greatest reduction in carbon dioxide emissions, and at the same time reduce the overall environmental impact by reducing the disturbance of biospheric material flows. Wind farms have high ecological and economic efficiency, while solar energy sources and bioelectric power plants – slightly less so. Geothermal and hydroelectric power plants have a low normalized cost of electricity, but they have relatively high values of material intensity. The environmental and economic efficiency of nuclear power is higher than that of gas and coal-fired power plants using carbon dioxide capture technologies; it occupies an intermediate position between renewable and traditional energy sources. An unexpected established fact is that gas and coal-fired power plants with carbon dioxide capture technologies have the same environmental and economic efficiency. The results obtained can be useful in making decisions about the possibility of prioritizing the development of individual low-carbon energy sources.

ЭЛЕКТРОСНАБЖЕНИЕ РЕСПУБЛИКИ ДАГЕСТАН: ОТ КОЛЛАПСА К БЕЗАВАРИЙНОСТИ И НАДЕЖНОСТИ

The article examines the regional problems of electricity supply. The role of the electric power industry in the socio-economic development of the country is noted. Global trends in the production and consumption of electric power are highlighted. Dagestan, before market transformations, fully provided itself with the energy produced in the republic, and over the past twenty years, electricity consumption has doubled, but its production has not increased, and moreover, in some years there has even been a decrease. The reasons for the sharp increase in electricity consumption by the population of the republic are the increase in living standards, housing construction in cities and the development of the shadow economy, especially mining activities. But the main problem in the article is not so much the shortage of energy itself, as the wear and tear of the grid complex. The wear rate of the networks is more than 20%. The loss of electricity in the networks exceeds 75% of the power consumption. The article emphasizes that without attracting large investments from the federal center, the reconstruction of the energy grid system is impossible. In parallel, the directions of development of distributed energy are highlighted: the construction of small hydroelectric power plants on mountain rivers, geothermal, solar and wind power plants. All this is aimed at ensuring trouble-free reliable electricity supply to the population.

Thermodynamic Performance Analysis of Geothermal Power Plant Based on Organic Rankine Cycle (ORC) Using Mixture of Pure Working Fluids

Thermodynamic Performance Analysis of Geothermal Power Plant Based on Organic Rankine Cycle (ORC) Using Mixture of Pure Working Fluids

Numerical study for effect of injection parameters on reservoir: A case study for Lahendong, Indonesia

A single-flash cycle of thermodynamic model coupled with a reservoir of numerical model has been developed through the COMSOL Livelink module to investigate the impact of the geofluid mass flow rate and injection temperature on production temperature and net output power of the power cycle. The geothermal reservoir model was established by using a thermal–hydraulic–mechanical (THM) module in COMSOL Multiphysics. Moreover, the single-flash cycle of the thermodynamics model was constructed in MATLAB. The geothermal reservoir conditions of Lahendong, North Sulawesi, Indonesia was adopted to simulate the geothermal power plants’ actual operation. The results revealed that the variation in geofluid mass flow rate and injection temperature impacted production temperature and net output power. The production temperature considerably decreased with an increase in the geofluid mass flow rate. However, the difference in production temperature between geofluid mass flow rates of 50 kg/s and 250 kg/s at 1st and 30th years were 0.23 K and 0.41 K, respectively. The net output power differences were also 16.204 MW and 15.349 MW, respectively. Finally, increasing the injection temperature correspondingly led to an increase in production temperature and net output power, even though the increment did not exceed 1 K and 0.002 MW, respectively.

Rare earth element extraction from geothermal brine using hybrid capacitive-deionisation process

Rare Earth Elements (REE) in geothermal brine include pollutants such as dissolved Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, lithium, and other ions. These REEs in geothermal brine, also popularly known as “Vitamins of the modern industry”, are vital for industries such as new energy vehicles, wind turbines, radar systems, laser crystals, etc., and harmful for agriculture and drinking purposes. Hence, identifying, quantifying, and extracting these REEs are essential and economical for a geothermal plant. The present study systematically investigates identifying and quantifying the REE and other essential ions in geothermal brine sources from Gujarat regions. For the extraction of REE from geothermal brine, geothermal brine treatment systems and their integration with automation control are designed in the present work. The proposed system filters geothermal brine and extracts REE through a hybrid filtration setup using capacitive deionization. Solar photovoltaic Water Filtration uses a hybrid Capacitive De-Ionization (CDI) treatment-based prototype to purify water and extract REE. The CDI method is an emerging technology in the desalination systems. It has far greater leverage over other desalination methods such as electrodialysis. The proposed design allows the simultaneous removal of various dissolved organic and inorganic contaminants in geothermal brine.

Evaluation and Optimization Based on Exergy in Kamojang Geothermal Power Plant Unit 3

The quality of production well from the Kamojang geothermal power plant unit 3 diminishes annually, whereas there has been a substantial rise in the demand for electrical energy in the region. This research focuses on optimizing the vacuum pressure in the main condenser by employing exergy analysis, a methodology grounded in the principles of the second law of thermodynamics. Exergy analysis offers insights into each system component's exergy efficiency and irreversibility. Furthermore, an energy assessment is conducted to offer insights into each component's energy consumption or utilization. Energy and exergy rates are computed for every state and component within the power plant, encompassing the steam receiving header, separator, demister, turbine, main condenser, inter condenser, after condenser, and cooling tower. The exergy analysis findings reveal that the exergy rate derived from the production well amounts to 95327 kW, generating 52882 kW of electricity and producing a system exergy efficiency of 55.47%. The turbine experiences the highest irreversibility, totaling 12874 kW. Adjustments are made to the main condenser vacuum pressure to optimize the system, aiming to identify the optimal setting that maximizes both exergy efficiency and power output. The optimization outcomes indicate that reducing the vacuum pressure in the main condenser leads to enhanced exergy efficiency and increased power output. The optimal vacuum pressure obtained is 0.1 bar, resulting in the highest exergy efficiency and output power of 57.42% and 54738 kW, respectively, with the lowest irreversibility of 32751.07 kW.

Evaluation and Optimization Based on Exergy in Kamojang Geothermal Power Plant Unit 3

The quality of production well from the Kamojang geothermal power plant unit 3 diminishes annually, whereas there has been a substantial rise in the demand for electrical energy in the region. This research focuses on optimizing the vacuum pressure in the main condenser by employing exergy analysis, a methodology grounded in the principles of the second law of thermodynamics. Exergy analysis offers insights into each system component's exergy efficiency and irreversibility. Furthermore, an energy assessment is conducted to offer insights into each component's energy consumption or utilization. Energy and exergy rates are computed for every state and component within the power plant, encompassing the steam receiving header, separator, demister, turbine, main condenser, inter condenser, after condenser, and cooling tower. The exergy analysis findings reveal that the exergy rate derived from the production well amounts to 95327 kW, generating 52882 kW of electricity and producing a system exergy efficiency of 55.47%. The turbine experiences the highest irreversibility, totaling 12874 kW. Adjustments are made to the main condenser vacuum pressure to optimize the system, aiming to identify the optimal setting that maximizes both exergy efficiency and power output. The optimization outcomes indicate that reducing the vacuum pressure in the main condenser leads to enhanced exergy efficiency and increased power output. The optimal vacuum pressure obtained is 0.1 bar, resulting in the highest exergy efficiency and output power of 57.42% and 54738 kW, respectively, with the lowest irreversibility of 32751.07 kW.

Lithuania’s geo-energy landscape: a brief overview of CCUS, hydrogen, and geothermal

Lithuanian energy landscape is changing because of a strong push to reduce carbon emissions and reliance of fossil-based energy production. EU climate directive promotes investments into carbon capture and storage technologies along with renewable energy resource development. CCUS, hydrogen and geothermal are some technologies which could promote reduction in carbon emissions and along with reducing dependence on fossil-based energy sources. Lithuania already has large potential for carbon and hydrogen storage and in past had a working geothermal power plant for district heating. In this work we revisit the carbon storage potential in Lithuania subsurface and provide a high-level estimate of potential of generating hydrogen energy from depleted hydrocarbon fields using in-situ methods. We also evaluate the prospects of development of geothermal energy production from deep Cambrian reservoirs where temperature above 85 °C has been documented.

Power generation prediction of a geothermal-thermoelectric hybrid system using intelligent models

This study focuses on the most effective use of energy resources, which is the main goal of sustainable energy systems. The first contribution of the research is to ensure that the waste and geothermal fluids generated during the geothermal energy production process are evaluated in the most efficient way and reused for energy production. For this purpose, a geothermal-thermoelectric hybrid experimental system has been designed to produce electrical energy through heat exchange and how waste thermal energy could be reused in this process has been examined. Experimental tests have been performed under electrical load and in the presence of real-time uncertainties such as temperature changes, thermal conductivity, electrical noise, heat losses and random variations in thermal interaction. The second main contribution of the study is to predict and evaluate different power generation performances in the Thermoelectric Generator (TEG) system, which is affected by the mentioned experimental limitations based on artificial intelligence models. In addition, the optimal prediction performance of artificial intelligence models using hyper-parameter optimization has also been compared. Experimental results have shown that intelligent models are a successful tool for energy prediction in geothermal power generation. As a result of the hyper-parameter optimization, each model is improved by ∼5 % to ∼30 % in various error metrics. However, it was observed that the decision tree-based learning techniques resulted in ∼46 % to ∼96 % less inaccurate predictions on various error metrics compared to other methods. Power production predictions obtained using intelligent models have been obtained with 98.7 % accuracy with LightGBM learning algorithms. Most of the models used to classify different hot and cold water levels exhibit very high classification performance. The results show the successful integration of artificial intelligence models in effectively utilizing waste thermal energy and adopting a sustainable approach to energy production.

The Exergy and Energy Analysis of Change Phase Steam in Patuha Geothermal Well Production

A Geothermal Power Plant Company in West Java Indonesia have capacity around 55MW. It company have increased the well production quality to keep up the Indonesia's energy demands. The power plant has been operated around ten years, it has ten geothermal production wells and two injection wells. The either of it wells has an abnormality. It wells has water dominated condition so, the separator equipment is required to separate the steam from water and vapor. Previous study indicated that subsurface water entering the broken reservoir pipe. That leaks in reservoir pipe was repaired in 2020. The impact after the pipe have been repaired it made the fluid characteristic of reservoir be vapor dominated. After that a separator as a steam separator is no longer required. The study compares the value energy and exergy power of the power plant. The calculations are performed from the well reservoir and all power plant equipment. According to the results of the energy study, the plant's energy efficiency after the transformation increased by 0.03%, from 19.48% to 19.52%. The exergy value of the brine in either wells (separated steam cycle) is also known to be 2.512,52 kW, beyond which the value will become zero.

Hydrogen energy: solution for renewable energy shortage

As the demand for renewable energy increases, people are now searching for clean energies that can ameliorate the existing circumstances. Fortunately, hydrogen energy offers an alternative with its adaptability in multiple aspects. Hydrogen, in comparison with wind power, photovoltaic cells, geothermal power, and hydropower, has stood out prominently in the aspects of conversion efficiency and carbon dioxide (CO2) production. This paper will delve into three methods of producing hydrogen as well as the obstacles related to storing and transporting it. Additionally, it will examine aspects of hydrogen energy and its potential to revolutionize the energy sector. Hydrogen is an inventive way of generating energy, as it does not produce any CO2 when produced as green hydrogen. Nevertheless, current ways of producing hydrogen are still harmful to the environment, and the storage of it still proves difficult. The pursuit of a future fueled by hydrogen brings both possibilities and significant challenges. The key lies in research, innovation, and infrastructure development as we strive to make hydrogen energy an integral part of an environmentally friendly energy model for future generations.

Analysis of thermal efficiency in Star Energy Gothermal Darajat

After years of operation, the plant will no longer operate optimally according to its design. The practice of the work cycle shows that the original value of thermal efficiency will always be below 100%, this is because during the cycle process of creating work, the energy received by the system by heat transfer will not be fully received and will be absorbed by the environment. In this research, thermal efficiency analysis was carried out in accordance with the first and second laws of thermodynamic efficiency and thermoeconomic calculations to calculate losses. Based on calculations that have been carried out, the thermal efficiency of the Star Energy Geothermal Darajat unit-3 geothermal power plant system is 21.72% with the largest exergy loss being in the condenser component of 62,219,418 kW with an exergy loss cost of 252,766,682.24 Rp/ days and the smallest is in the cooling tower of 599,362 kW with exergy loss costs of 23,655,907.11. Rp/day from the following results it can be seen that this efficiency value depends on the performance of each component.

Development and assessment of a newly developed renewable energy-based hybrid system with liquid hydrogen storage for sustainable development

One of the most effective ways to address the environmental issues triggered by fossil fuels is through the use of renewable energy. In this study, clean and sustainable power and hydrogen generation with three renewable energy sources, a wind-solar-geothermal assisted hybrid plant is planned, investigated, and analyzed. An exhaustive thermodynamic performance analysis is executed to specify the system efficiency by the way energy and exergy efficiency methods. Moreover, this developed cycle comprises a solar photovoltaic (PV) unit, a triple flash geothermal power plant, wind turbines for power generation, and a hydrogen generation and liquefaction unit. Additionally, a case study for Isparta is conducted using actual data on wind speed and solar radiation. A parametric analysis, on the other hand, is conducted to figure out the consequences of the examined cycle's performance. In light of the examination outcomes, the developed plant's power rate is figured as 9942 kW. The hydrogen generation rate and sustainability index are also figured out as 0.02143 kg/s and 2.003, respectively. Finally, the proposed hybrid cycle encloses an energetic and exergetic performance of 32.755 % and 50.06 %, respectively.

Geochemical modelling of heavy metal deposition in a geothermal heat exchanger

Heavy metal deposition and corrosion of carbon and low alloy steels exposed to geothermal two-phase fluids and brine solutions under acidic fluid conditions have been widely reported. Similarly, near neutral conditions can result in the precipitation of arsenic and antimony scales that can limit heat exchange. Geochemistry modelling has been undertaken to explain observed deposition and scaling in a two-phase geothermal fluid heat exchanger with a view to predicting the risk of heavy metal deposition and corrosion and heavy metal scaling in geothermal process fluids for new and existing energy facilities. Understanding of the geochemical parameters that control deposition, scaling and corrosion will allow the prediction of the risk of heavy metal deposition and scaling at the design stage for geothermal energy plants and assist in the selection of materials and processes that will give reliable long-term performance. The developed models have application in other industries for prediction of risk of scaling and corrosion and for process development support for example for the gettering of heavy metals from contaminated liquids and soils.