scholarly journals Geothermal Power Generation

2021 ◽  
Author(s):  
Ziyodulla Yusupov ◽  
Mohamed Almaktar

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.

Author(s):  
Yoshinobu Nakao ◽  
Toru Takahashi ◽  
Yutaka Watanabe

Geothermal energy is considered a comparatively abundant renewable energy resource. The geothermal power generation system has negligible environmental impact (approximately 0.015kg-CO2/kWh), and it is expected to help prevent carbon dioxide emissions to the atmosphere. On the other hand, in our institute, we have developed general purpose software (EnergyWin™) to analyze the thermal efficiencies of power generation systems easily and rapidly. Such software can not only analyze the plant performance but also investigate the effect of the performance-deteriorated equipment or air condition change on power output quantitatively. Using this software, we have developed a new plant performance analysis system based on actual operation data for geothermal power plants. Then, applying the system to existing facilities, we have analyzed the plant performance and evaluated the effectiveness of the plant maintenance strategy during periodic inspection for consistency.


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.


2018 ◽  
Vol 4 (7) ◽  
Author(s):  
Andrijana Stevanović ◽  
Boban Jolović

One of the most used renewable energy sources worldwide is geothermal energy. Itrepresents the heat, originated by natural processes happen in the Earth interior. The hot springsphenomena are the most frequent natural manifestation of geothermal activity.Geothermal potentiality of some area can be estimated based on geothermal gradient. Geothermalgradient is a conductive terrestrial parameter that represents the degree of increasing of the Earthtemperature vs. depth. It is usually expressed in ⁰C/m or ⁰C/km. Different areas have differentthermal gradients and thus different geothermal potential. Generally, higher geothermal gradientscorrespond to areas containing more geothermal energy.Geothermal characteristics of the territory of the Republic of Srpska are closely related to itscomplex geological setting. It is the reason why geothermal characteristics are different from areato area. Higher geothermal potentiality is recognised in the northern parts of the entity, in the firstorder in Semberija, Posavina and Banja Luka regions.The use of geothermal energy with different fluid temperatures can be considered throughthe Lindaldiagram, who firstly proposed acomprehensive scale with appropriate temperatures for differentuses. High temperature fluids are mostly used for electricity production and moderate and lowtemperature fluids for the direct use.Despite the fact that the territory of the Republic of Srpska hasfavourable geothermal properties, utilization of this kind of renewable energy resource isinadequate. Especially indicative are data about the use of geothermal energy by heat pumps (inbad sense) in comparison with praxis of developed countries.Chemical composition of thermal waters plays very important role and can be used in itsexploration stage, for analyses of possibility of its use and for prediction of exploitation effects, aswell. This kind of renewable energyresource, highly ecologically recommended, must be consideredmore seriously in the future in the Republic of Srpska. Furthermore, it must be put into the energystrategic documentsin appropriate manner.


2021 ◽  
Vol 3-4 (185-186) ◽  
pp. 109-125
Author(s):  
Myroslav Podolskyy ◽  
Dmytro Bryk ◽  
Lesia Kulchytska-Zhyhailo ◽  
Oleh Gvozdevych

An analysis of Ukraine’s sustainable development targets, in particular in the field of energy, resource management and environmental protection, are presented. It is shown that regional energetic is a determining factor for achieving the aims of sustainable development. Changes in the natural environment in Ukraine due to external (global) and internal (local) factors that are intertwined and overlapped can cause threats to socio-economic development. It is proved that in the areas of mining and industrial activity a multiple increase in emissions of pollutants into the environment are observed. The comparison confirmed the overall compliance of the structure of consumption of primary energy resources (solid fossil fuels, natural gas, nuclear fuel, oil and petroleum products, renewable energy sources) in Ukraine and in the European Union, shows a steaby trend to reduce the share of solid fuels and natural gas and increasing the shares of energy from renewable sources. For example, in Ukraine the shares in the production and cost of electricity in 2018 was: the nuclear power plants – 54.33 % and in the cost – 26.60 %, the thermal power – 35.95 and 59.52 %, the renewable energy sources – 9.6 and 13.88 %. The energy component must be given priority, as it is crucial for achieving of all other goals of sustainable development and harmonization of socio-economic progress. The paper systematizes the indicators of regional energy efficiency and proposes a dynamic model for the transition to sustainable energy development of the region.


Author(s):  
Reynir S. Atlason ◽  
Oli P. Geirsson ◽  
Ari Elisson ◽  
Runar Unnthorsson

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.


Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 67
Author(s):  
Rakkyung Ko ◽  
Sung-Kwan Joo

Virtual power plants (VPPs) have been widely researched to handle the unpredictability and variable nature of renewable energy sources. The distributed energy resources are aggregated to form into a virtual power plant and operate as a single generator from the perspective of a system operator. Power system operators often utilize the incentives to operate virtual power plants in desired ways. To maximize the revenue of virtual power plant operators, including its incentives, an optimal portfolio needs to be identified, because each renewable energy source has a different generation pattern. This study proposes a stochastic mixed-integer programming based distributed energy resource allocation method. The proposed method attempts to maximize the revenue of VPP operators considering market incentives. Furthermore, the uncertainty in the generation pattern of renewable energy sources is considered by the stochastic approach. Numerical results show the effectiveness of the proposed method.


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

2014 ◽  
Vol 21 (2) ◽  
pp. 327-336 ◽  
Author(s):  
Robert Kasperek ◽  
Mirosław Wiatkowski

Abstract Adopted in 2009, the Directive of the European Parliament and of the Council on the promotion of the use of energy from renewable sources sets out the rules for how Poland is to achieve the 15% target of total primary energy from renewables by 2020. However, there are fears that the goals set out in this Directive may not be met. The share of Renewable Energy Sources (RES) in national energy consumption (150 TWh) is estimated at 8.6 TWh in 2009 and 12 TWh in 2011 (5.7 and 8% respectively). The level of RES in Poland until 2005 was approx. 7.2%. The analysis of RES technologies currently in use in Poland shows that in terms of the share in the total capacity, the 750 hydro-electric power plants which are currently in operation (with the overall capacity of almost 0.95 GW) are second only to wind power stations (2 GW). The authors have studied the Nysa Klodzka River in terms of possible locations for hydro-electric facilities. Eight locations have been identified where power plants might be constructed with installed capacities ranging from 319 to 1717 kW. The expected total annual electric power generation of these locations would stand at approx. 37.5 GWh.


2019 ◽  
Vol 17 (1) ◽  
pp. 25
Author(s):  
La Ode Musa ◽  
Abdul Rahman ◽  
Ikral Gapshel ◽  
Triska Sombokanan

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%.


2021 ◽  
Vol 236 ◽  
pp. 02016
Author(s):  
Jiaying Zhang ◽  
Yingfan Zhang

The power output of the photovoltaic power generation has prominent intermittent fluctuation characteristics. Large-scale photovoltaic power generation access will bring a specific impact on the safe and stable operation of the power grid. With the increase in the proportion of renewable energy sources such as wind power and photovoltaics, the phenomenon of wind abandonment and light abandonment has further increased. The photovoltaic power generation prediction is one of the critical technologies to solve this problem. It is of outstanding academic and application value to research photovoltaic power generation prediction methods and systems. Therefore, accurately carrying out the power forecast of photovoltaic power plants has become a research hot point in recent years. It is favored by scholars at home and abroad. First, this paper builds a simulation model of the photovoltaic cell based on known theoretical knowledge. Then it uses the density clustering algorithm (DBSCAN) in the clustering algorithm and classifies the original data. Finally, according to a series of problems such as the slow modeling speed of photovoltaic short-term power prediction, the bidirectional LSTM photovoltaic power prediction model, and CNN-GRU photovoltaic power prediction model based on clustering algorithm are proposed. After comparing the two models, it is concluded that the bidirectional LSTM prediction model is more accurate.


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