scholarly journals Geothermal energy as a source of electricity. A worldwide survey of the design and operation of geothermal power plants

1980 ◽  
Author(s):  
R. DiPippo
Keyword(s):  
Geothermal Energy ◽  
Power Plants ◽  
Geothermal Power

scholarly journals A Project To Estimate The Power Capacity Of Geothermal Power Plants Based On The Enthalpy Of Geothermal Fluid And Plant Design

2021 ◽  
Author(s):  
Obumneme Oken
Keyword(s):  
Power Plant ◽  
Geothermal Energy ◽  
Electricity Generation ◽  
Power Plants ◽  
Hot Water ◽  
Power Capacity ◽  
Geothermal Fluid ◽  
Direct Heating ◽  
Single Flash ◽  
Geothermal Power

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.

Go With the Flow: The Evolvement of Geothermal Wellhead Maintenance at the Hellisheidi Power Plant

2014 ◽  
Author(s):  
Reynir S. Atlason ◽  
Oli P. Geirsson ◽  
Ari Elisson ◽  
Runar Unnthorsson
Keyword(s):  
Power Plant ◽  
Geothermal Energy ◽  
Power Plants ◽  
Waiting Times ◽  
District Heating ◽  
Real Data ◽  
Energy Company ◽  
Power Company ◽  
Geothermal Power ◽  
Maintenance Model

Iceland relies greatly on geothermal energy, for electricity, district heating and industrial activities. It is therefore of great importance that the maintenance on site is carried out quite successfully to minimize down time. Reykjavik Energy is the largest energy company in Iceland utilizing geothermal energy. The company operates two cogenerating geothermal power plants, Hellisheidi (303 MWe and 133 MWt) and Nesjavellir (120 MWe and 300 MWt). In this study we investigate the development of the wellhead maintenance at the Hellisheidi geothermal power plant. We look at the maintenance recommendations provided to on-site employees and how maintenance procedures have developed since the power plant began its operations. We investigate real data retrospectively and use it to calculate expected waiting times between repairs. The result is a maintenance model based on the observed and statistically analyzed data provided by the power company on the maintenance procedures. Such model should prove of great significance to other geothermal power plants in the early stages of planning the wellhead maintenance.

Toward Cleaner Geothermal Energy Utilization: Capturing and Sequestering CO $$_2$$ 2 and H $$_2$$ 2 S Emissions from Geothermal Power Plants

2014 ◽  
Vol 108 (1) ◽  
pp. 61-84 ◽  
Author(s):  
Edda S. P. Aradóttir ◽  
Ingvi Gunnarsson ◽  
Bergur Sigfússon ◽  
Gunnar Gunnarsson ◽  
Bjarni M. Júliusson ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Power Plants ◽  
Energy Utilization ◽  
Geothermal Power

scholarly journals Analisis Performansi Turbin dan Generator di PLTP Lahendong Unit 1 Tomohon

2019 ◽  
Vol 17 (1) ◽  
pp. 25
Author(s):  
La Ode Musa ◽  
Abdul Rahman ◽  
Ikral Gapshel ◽  
Triska Sombokanan
Keyword(s):  
Geothermal Energy ◽  
Power Plants ◽  
Electrical Energy ◽  
Analysis Method ◽  
Steam Quality ◽  
Average Quality ◽  
Turbine Efficiency ◽  
Generator Unit ◽  
Geothermal Power

Lahendong Geothermal power plant is one of the Geothermal power plants in Indonesia which has four units and it be able to generate 4 × 20 MW of electrical energy by utilizing geothermal energy in the form of steam that supplied from wells created by Pertamina. The aim of this study is to determine the performance of the turbine and generator unit 1 which has been operated since 2001 by using thermodynamic analysis method calculating the steam quality and turbine work. Afterwards, turbine efficiency, turbine power and generator power were obtained. The average quality of geothermal steam at Lahendong in 2001 and 2015 were 0.8002 and 0.8065. Turbine’s performance decreased in 2001 (664.021 kJ / kg) until 2015 (640.799 kJ / kg), with the highest generator rotation tolerance of 0.9%.

scholarly journals Utilizing renewable resources – converting geothermal energy to electricity

2020 ◽  
Author(s):  
Miljan Vlahović ◽  
◽  
Milica Vlahović ◽  
Zoran Stević ◽  
◽  
...  
Keyword(s):  
Renewable Resources ◽  
Geothermal Energy ◽  
Power Plants ◽  
Hot Water ◽  
Geothermal Heat ◽  
Geothermal Resources ◽  
Binary Cycle ◽  
Flash Tank ◽  
Solid Soil ◽  
Geothermal Power

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.

scholarly journals A Project To Estimate The Power Capacity Of Geothermal Power Plants Based On The Enthalpy Of Geothermal Fluid And Plant Design

2021 ◽  
Author(s):  
Obumneme Oken
Keyword(s):  
Power Plant ◽  
Power Output ◽  
Geothermal Energy ◽  
Power Plants ◽  
Hot Water ◽  
Geothermal Resource ◽  
Power Capacity ◽  
Geothermal Fluid ◽  
Single Flash ◽  
Geothermal Power

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.

scholarly journals Geothermal Power Generation

2021 ◽  
Author(s):  
Ziyodulla Yusupov ◽  
Mohamed Almaktar
Keyword(s):  
Power Generation ◽  
Geothermal Energy ◽  
Power Plants ◽  
Sustainable Energy ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
High Resource ◽  
Exploration Risk ◽  
Geothermal Power ◽  
Bulk Power

Bulk power system based on fossil fuels becomes less reliable and stable in economic terms, technically more labor-consuming and harmful environmental impact. These problems have led many countries to find ways to supply the electricity from a green and sustainable energy source. The electricity derived from renewable energy sources such as hydro, solar, wind, biomass and geothermal refers to as green and sustainable energy. Geothermal energy is not only utilized for electric power generation, but it is also exploited to generate environmentally friendly heat energy. As of the end of 2018, geothermal global cumulative installed capacity exceeded 13 GW, generated an energy of about 630 peta joule (PJ). This chapter presents the geothermal energy resource in terms of the types of power plants, principle of the electricity generation and current world status of geothermal resource utilization. The issues such as advantages and disadvantages of geothermal energy economically and environmentally and means to overcome shortcomings are also considered. The main barriers for the development of geothermal industry include high resource and exploration risk, overall high development cost particularly drilling, and inadequate financing and grant support. The global averaged cost of electricity for the geothermal facility is nearly 0.072 USD/kWh as compared to 0.056 for onshore wind and 0.047 USD/kWh for hydropower. However, the technology is rather competitive to other renewables such as concentrating solar power (0.185 USD/kWh) and offshore wind (0.127 USD/kWh). Meanwhile, further research and development is critically needed to eliminate the non-condensable gases (NCGs) associated with the geothermal power generation.

scholarly journals Wellhead Power Plants Improvement by Introduction of Double Flashing Cycle

2019 ◽  
pp. 24-32
Author(s):  
Thomas Mutero ◽  
Peter Muchiri ◽  
Nicholas Mariita
Keyword(s):  
Power Plant ◽  
Geothermal Energy ◽  
Power Plants ◽  
Low Pressure ◽  
Geothermal Field ◽  
Power Cycle ◽  
Single Flash ◽  
Geothermal Power ◽  
Installed Capacity

Kenya Electricity Generating Company Ltd (KenGen) has harnessed geothermal energy for over thirty seven years at the Olkaria geothermal field. The total installed capacity of geothermal energy in Kenya currently stands at 703.5 MW generated mostly by single flash and binary geothermal power plants. In the 1990s KenGen considered the Wellheads concept in which modular containerized single flash power plants were to be designed, customized and built on a wellpad for optimized well potential; this approach has largely been successful currently having an installed capacity of 83.5 MW and accounting for 15.7% of KenGen's total geothermal installed capacity. This was done to address an inherent deficiency in the construction of conventional geothermal power plants which was identified as the long period taken to put up the power plants. The wells that have been drilled by KenGen and GDC, tested and shut in awaiting the installation of power plants are rated at about 600 MW. The Wellhead power plant cycle is a single flash geothermal power plant; this research intended to improve the current Wellheads power cycle by introducing a second low pressure separator to harness more energy from the wellheads, design a turbine to be driven by the low pressure steam and evaluate an economic justification for introducing the double flashing cycle. A case study was carried out at Wellhead 914 and Wellhead 915. Data collected indicated that the combined mass flow rate of brine from wells in the two wellpads was 240.4 tonne per hour. This brine was saturated at 13.5 bar-a and at a temperature of 193.40C as it exits the high pressure separator for disposal. The optimal pressure of the low pressure separation was designed at 2.5 bar-a, 127.40C and had an ability to generate 3871 kW of electric power. A turbine operating at a steam inlet pressure of 2.5 bar-a, a speed of 6804 rpm and having an exhaust pressure of 0.075 bar-a was designed. The designed turbine had 4 stages of both stationary and moving blades with a maximum rotor disc diameter of 0.62 meters and an output of 4195 kW. The simple payback period for this project was estimated to be 1.9 years with a rate of return on investment of 42.24%. This would also minimize energy wastage by improving efficiency and footprints on the environment arising from the Wellhead power plants.

scholarly journals The Geothermal Power Plants of Amiata Volcano, Italy: Impacts on Freshwater Aquifers, Seismicity and Air

2021 ◽  
Author(s):  
Andrea Borgia ◽  
Alberto Mazzoldi ◽  
Luigi Micheli ◽  
Giovanni Grieco ◽  
Massimo Calcara ◽  
...  
Keyword(s):  
Water Table ◽  
Geothermal Energy ◽  
Power Plants ◽  
Fine Particles ◽  
Cooling Towers ◽  
Induced Earthquakes ◽  
Hydrologic Impacts ◽  
Geothermal Power ◽  
Freshwater Aquifers ◽  
Type Power

Production of geothermal energy for electricity at Amiata Volcano uses flash-type power plants with cooling towers that evaporate much of the geothermal fluid to the atmosphere to condense the geothermal vapour extracted. Because the flash occurs also within the geothermal reservoir, it causes a significant depressurization within it that, in turns, results in a drop of the water table inside the volcano between 200 and 300 m. The flow rates of natural springs around the volcano have also substantially decreased or ceased since the start of geothermal energy exploitation. Continuous recording of aquifer conditions shows substantial increases in salinity (>20%) and temperature (>2°C) as the water table falls below about 755–750 m asl. In addition to hydrologic impacts, there are also a large numbers of induced earthquakes, among which the ML 3.9, April 1, 2000 earthquake that generated significant damage in the old villages and rural houses. Relevant impacts on air quality occur when emissions are considered on a per-MW basis. For example, CO2+CH4 emissions at Amiata are comparable to those of gas-fired power plants (1), while the acid-rain potential is about twice that of coal-fired power plants. Also, a significant emission of primary and secondary fine particles is associated with the cooling towers. These particles contain heavy metals and are enriched in sodium, vanadium, zinc, phosphorous, sulphur, tantalium, caesium, thallium, thorium, uranium, and arsenic relative to comparable aerosols collected in Florence and Arezzo (2). Measurements have shown that mercury emitted at Amiata comprises 42% of the mercury emitted from all Italian industries, while an additional comparable amount is emitted from the other geothermal power plants of Tuscany (3). We believe that the use of air coolers in place of the evaporative cooling towers, as suggested in 2010 by the local government of Tuscany (4), could have and can now drastically reduced the environmental impact on freshwater and air. On the opposite side of the coin, air-coolers would increase the amount of reinjection, increasing the risk of induced seismicity. We conclude that the use of deep borehole heat exchangers could perhaps be the only viable solution to the current geothermal energy environmental impacts.

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