scholarly journals Regeneration of Electrical Energy from Waste Geothermal Fluid in Geothermal Power Plants

2019 ◽  
Vol 2 (3) ◽  
pp. 525-531
Author(s):  
Mahmut Hekim ◽  
Engin Cetin

Geothermal power plants are the plants that provide the conversion of thermal energy in geothermal fluid to electrical energy as a result of the extraction of underground hot water resources to the earth by drilling. The total installed power of geothermal power plants in the field of geothermal resources in Turkey has reached 1,336 MW. The geothermal fluid, which is used for electric power generation in geothermal power plants, is re-injected into the underground wells after electrical energy production. For efficient generation of electrical energy in geothermal power plants, it is aimed to reuse the waste heat energy within the geothermal fluid before it is sent to the re-injection well. To achieve this aim, thermoelectric generator modules which convert waste heat energy to electrical energy can be used. In this study, a thermoelectric generator-based geothermal power plant simulator that converts geothermal fluid waste heat into electrical energy is installed and commissioned in the laboratory conditions.

Author(s):  
Obumneme Oken

Nigeria has some surface phenomena that indicate the presence of viable geothermal energy. None of these locations have been explored extensively to determine the feasibility of sustainable geothermal energy development for electricity generation or direct heating. In this context, the present study aims to provide insight into the energy potential of such development based on the enthalpy estimation of geothermal reservoirs. This particular project was conducted to determine the amount of energy that can be gotten from a geothermal reservoir for electricity generation and direct heating based on the estimated enthalpy of the geothermal fluid. The process route chosen for this project is the single-flash geothermal power plant because of the temperature (180℃) and unique property of the geothermal fluid (a mixture of hot water and steam that exists as a liquid under high pressure). The Ikogosi warm spring in Ekiti State, Nigeria was chosen as the site location for this power plant. To support food security efforts in Africa, this project proposes the cascading of a hot water stream from the flash tank to serve direct heat purposes in agriculture for food preservation, before re-injection to the reservoir. The flowrate of the geothermal fluid to the flash separator was chosen as 3125 tonnes/hr. The power output from a single well using a single flash geothermal plant was evaluated to be 11.3 MW*. This result was obtained by applying basic thermodynamic principles, including material balance, energy balance, and enthalpy calculations. This particular project is a prelude to a robust model that will accurately determine the power capacity of geothermal power plants based on the enthalpy of fluid and different plant designs.


2020 ◽  
Author(s):  
Paolo Basile ◽  
Roberto Brogi ◽  
Favaro Lorenzo ◽  
Tiziana Mazzoni

<p><span><span>Social consensus is a </span><span>condition precedent for any intervention having an impact on the territory, such as geothermal power plants. Therefore, private investors studied and proposed innovative solution for the exploitation of the medium enthalpy geothermal resource, with “zero emissions” in atmosphere, with the target of minimizing its environmental impact. “Montenero” project, developed by GESTO Italia, complies with this precondition.</span></span></p><p><span><span>The area covered b</span><span>y the exploration and exploitation permit is located on the northern edge of the great geothermal anomaly of Mt. Amiata (Tuscany), about 10 km north of the geothermal field of Bagnore, included in the homonymous Concession of Enel Green Power.</span></span></p><p><span><span>The geological - structural setting of the area around the inactive volc</span><span>ano of Mt. Amiata has been characterized by researches for the geothermal field of Bagnore, carried out by Enel Green Power over the years. The geothermal reservoir is present in the limestone and evaporitic rocks of the “Falda Toscana”, below which stands the Metamorphic Basement, as testified by the wells of geothermal field of Bagnore. The foreseen reservoir temperature at the target depth of 1.800 m is 140 °C, with an incondensable gas content of 1,8% by weight.</span></span></p><p><span><span>The project was presented to the authorities in 2013 and it is </span><span>now undergoing exploitation authorization and features the construction of a 5 MW ORC (Organic Ranking Circle) binary power plant. The plant is fed by three production wells for a total mass flow rate of 700 t/h. The geothermal fluid is pumped by three ESPs (Electrical Submersible Pump) keeping the geothermal fluid in liquid state from the extraction through the heat exchangers to its final reinjection three wells.</span></span></p><p><span><span>The reinjection temperature is 70 °C and the circuit pressure is maintained above the </span><span>incondensable gas bubble pressure, i.e. 40 bar, condition which prevents also the formation of calcium carbonate scaling. The confinement of the geothermal fluid in a “closed loop system” is an important advantage from the environmental point of view: possible pollutants presented inside the geothermal fluid are not released into the environment and are directly reinjected in geothermal reservoir.</span></span></p><p><span><span>The </span><span>environmental authorization procedure (obtained) has taken into account all the environmental aspects concerning the natural matrices (air, water, ground, ...) potentially affected by the activities needed for the development, construction and operation of “Montenero” ORC geothermal power plant. A numerical modeling was designed and applied in order to estimate the effect of the cultivation activity and to assess the reinjection overpressure (seismic effect evaluation). The project also follows the “best practices” implemented in Italy by the “Guidelines for the usage of medium and high enthalpy geothermal resources” prepared in cooperation between the Ministry of Economic Development and the Ministry of the Environment.</span></span></p>


The growing concern on energy conservation and reduction of carbon footprint has led to a lot of inventions and innovations in terms of energy-efficient technologies in all the energy consuming applications. The automobile sector is a crucial zone where these technologies have a major role to play due to the sheer abundance of the number of automobiles.Many small refinements, alterations and innovations are happening in this field which has led to furthermore energy economic automobiles than before.But even in an advanced internal combustion engine, about two-thirds of fuel consumed by an automobile is discharged into the surroundings as waste heat. The effect of this is the increase in the surrounding air temperature which in turn contributes significantly to global warming. This paper proposes amethod to reduce the emission of heat from automobiles by designing and implementinga waste heat recovery system for internal combustion (IC) engines. The key aim is to reduce the amount of heat released into the environment and to convert it into useful energy. A thermoelectric generator (TEG) assembly is used to directly convert the wasted heat energy from the automobile into electrical energy. This electrical energy is conditioned using a Cukconverter and maximum power point tracking (MPPT) algorithm is embedded in the converter for impedance matching and maximum power transfer from TEG to the converter. The conditioned output is used to charge the battery of the vehicle. This methodologyalso increases the energy efficiency of the vehicle as a higher capacity battery can be employed.The proposed system can work well under varying temperature conditions to give a constant output. It can be implemented in any mechanical/ electrical systems were there is wastage of heat energy like gas pipelines, wearable electronics, space probes, cookstoves, boilers, thermal vision, etc. One of the thrust areas where this technology can be effectively utilized in today’s world is in electric vehicles where the energy efficiency is the most important factor.


2021 ◽  
Vol 20 (4) ◽  
pp. 127-132
Author(s):  
Md Abdullah Al Rakib Rakib ◽  
Md. Saniat Rahman Zishan ◽  
Md. Abid Hasan Abid

In this project, heat energy is used for generatingelectrical energy by a conversion process. The energy harvestingfrom the heat of motorbike has become a new source of portableenergy for rechargeable gadgets. In contrary, the conventionalnonrenewable energy sources have likewise added to anexpansion in contamination on the planet and a disintegration ofhuman wellbeing. From the electrical energy, the mobile phonewill be charged. A thermoelectric generator has been connectedto the hot portion of the motorbike and while riding the bike, anykind of chargeable device will get charged. The prototype of thisresearch work has effectively harvested electrical energy fromheat using thermoelectric generator and has managed to provideenough power at different speeds of the motorbike.


Author(s):  
Miljan Vlahović ◽  
◽  
Milica Vlahović ◽  
Zoran Stević ◽  
◽  
...  

According to the official definition, approved by the European Geothermal Energy Council (EGEC), geothermal energy is energy accumulated as heat below the surface of solid soil. Geothermal energy is thermal energy generated and stored in the Earth. It is generally defined as the part of geothermal heat that can be directly utilized as heat or converted into other types of energy. Geothermal resources vary by location and depth towards the Earth's core. Their use is possible for different purposes depending on their temperature. This paper presents the harnessing geothermal resources for electricity generation. There are three main types of geothermal power plants: dry steam plants, flash steam plants, and binary cycle plants. Dry steam plants pipe hot steam from underground into turbines, which powers the generator to provide electricity. Flash steam plants pump hot water from underground into a cooler flash tank. The formed steam powers the electricity generator. Binary cycle plants pump hot water from underground through a heat exchanger that heats a second liquid to transform it into steam, which powers the generator. In all mentioned systems the used fluids are recycled. It can be concluded that geothermal power plants work similarly to other power plants, but providing the steam for starting the turbine from the earth's interior. The fact that used fluids return to the ground makes geothermal energy resources renewable.


2020 ◽  
Vol 5 (3) ◽  
pp. 58-61

Energy crisis is major problem in this era. Thermoelectric generator is a promising solution for this problem. This research aims to recover waste heat energy from automobile by converting it into electrical energy using thermoelectric generator. Thermoelectric generator is applied at automobile exhaust system to produce electrical energy from heat energy directly with a phenomenon called see-beck effect. This work develops a heat exchanger model with thermoelectric generator for automobile waste heat recovery in which heat source and cold sink are actually modeled. Main emphasis is put on effective temperature difference across the TEGs to get better performance of the exhaust waste heat recovery system. This research shows that the model is able to produce up to 2.67 W energy using 3 Numbers of TEGs in this design.


Author(s):  
Obumneme Oken

Surface phenomena that signal the presence of viable geothermal energy can be found in various locations in Nigeria. None of these locations have been explored extensively to determine the feasibility of sustainable geothermal energy development for electricity generation or direct heating purposes. In this context, the present study aims to provide insight into the energy potential of such development based on the enthalpy estimation of geothermal reservoirs. This particular project was conducted to determine the power output from a geothermal resource given an estimated enthalpy of the geothermal fluid. The process route chosen for this project is the single-flash geothermal power plant because of the temperature (180℃) and unique property of the geothermal fluid (a mixture of hot water and steam that exists as a liquid under high pressure). The Ikogosi warm spring in Ekiti State, Nigeria was chosen as the site location for this power plant. To support food security efforts in Africa, this project proposes the cascading of a hot water stream from the flash tank to serve direct heat purposes in agriculture for food preservation, before re-injection to the reservoir. The flowrate of the geothermal fluid to the flash separator was chosen as 3125 tonnes/hr. The power output from a single well using a single flash geothermal plant was evaluated to be 11.3 MW*. This result was obtained by applying basic thermodynamic principles, including material balance, energy balance, and enthalpy calculations. This particular project is a prelude to a robust model that will accurately determine the power capacity of geothermal power plants based on the enthalpy of geothermal fluid, size of the geothermal resource, and different plant designs. I hope that the knowledge gained from the study will promote best practices in geothermal engineering and emphasize appropriate planning for, and implementation of, geothermal plants.


2020 ◽  
Vol 6 (27) ◽  
pp. eaaz5264
Author(s):  
Yoshitaka Nakamura ◽  
Yuki Sakai ◽  
Masaki Azuma ◽  
Shin-ichi Ohkoshi

In thermal and nuclear power plants, 70% of the generated thermal energy is lost as waste heat. The temperature of the waste heat is below the boiling temperature of water. Here, we show a long-term heat-storage material that absorbs heat energy at warm temperatures from 38°C (311 K) to 67°C (340 K). This unique series of material is composed of scandium-substituted lambda-trititanium-pentoxide (λ-ScxTi3−xO5). λ-ScxTi3−xO5 not only accumulates heat energy from hot water but also could release the accumulated heat energy by the application of pressure. λ-ScxTi3−xO5 has the potential to accumulate heat energy of hot water generated in thermal and nuclear power plants and to recycle the accumulated heat energy on demand by applying external pressure. Furthermore, it may be used to recycle waste heat in industrial factories and automobiles.


2015 ◽  
Vol 787 ◽  
pp. 782-786 ◽  
Author(s):  
R. Prakash ◽  
D. Christopher ◽  
K. Kumarrathinam

The prime objective of this paper is to present the details of a thermoelectric waste heat energy recovery system for automobiles, more specifically, the surface heat available in the silencer. The key is to directly convert the surface heat energy from automotive waste heat to electrical energy using a thermoelectric generator, which is then regulated by a DC–DC Cuk converter to charge a battery using maximum power point tracking. Hence, the electrical power stored in the battery can be maximized. Also the other face of the TEG will remain cold. Hence the skin burn out accidents can be avoided. The experimental results demonstrate that the proposed system can work well under different working conditions, and is promising for automotive industry.


2021 ◽  
Author(s):  
Benjamin Adams ◽  
Jonathan Ogland-Hand ◽  
Jeffrey M. Bielicki ◽  
Philipp Schädle ◽  
Martin Saar

<p><b>Abstract</b></p><p>Sedimentary basins are ubiquitous, naturally porous and permeable, and the geothermal heat in these basins can be extracted with geologic water or CO<sub>2</sub> and used to generate electricity. Despite this, the broad potential that these formations may have for electricity generation is unknown. Here we investigate this potential, which required the creation of the <u>gen</u>eralizable <u>GEO</u>thermal techno-economic simulator (genGEO). genGEO is built with only publicly available data and uses five standalone, but integrated, models that directly simulate all components of geothermal power plants to estimate electricity generation and cost. As a result of this structure, genGEO, or a portion of it, can be applied or extended to study any geothermal power technology. In contrast, the current techno-economic tools for geothermal power plants rely on characterizations of unpublished ASPEN results and are thus not generalizable enough to be applied to sedimentary basin geothermal power plants which use subsurface CO<sub>2</sub>.</p> <p>In this study, we present genGEO as open-source software, validate it with industry data, and compare its estimates to other geothermal techno-economic tools. We then apply genGEO to sedimentary basin geothermal resources and find that using CO<sub>2</sub> as a subsurface heat extraction fluid compared to water decreases the cost of geothermal electricity across most geologic conditions that are representative of sedimentary basins. Using genGEO results and p50 geologic data, we produce supply curves for sedimentary basin geothermal power plants in the U.S., which suggests that there is present-day potential to profitably increase the capacity of geothermal power by ~10% using water as the subsurface heat extraction fluid. More capacity is available at lower cost when CO<sub>2</sub> is used as the subsurface fluid, but realizing this capacity requires geologically storing between ~2 and ~7 MtCO<sub>2</sub>/MW<sub>e</sub>. But developing sedimentary basin resources in the short-term using subsurface water may not eliminate options for CO₂-based power plants in the long-term because the least-cost order of sedimentary basins is not the same for both CO<sub>2</sub> and water. With sufficient geologic CO<sub>2</sub> storage, developing sedimentary basins using CO<sub>2</sub>- and water-based power plants may be able to proceed in parallel.</p>


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