Paper presents cost – benefit analysis of biogas
CHP plant. It will cover the technical characte... more Paper presents cost – benefit analysis of biogas CHP plant. It will cover the technical characteristics of different biogas CHP plant with emphasis on energy efficiency and costs for biogas power plants. Comparison of electrical efficiency and overall (CHP) efficiency for different types of biogas power plants will also be presented
Paper deals with calculation and design of the heat
pumps that are used for purposes of heating ... more Paper deals with calculation and design of the heat pumps that are used for purposes of heating and cooling. Heat pumps are systems that draw heat from one source (earth, water, air or ambient) and transfer it to another. Their operation is described by Carnot circular process, in which thermal energy is taken from one body to working medium and then from a working medium to the heated body. Energy put in the process is equal to the energy needed for moving and compression of the working medium. Authors have calculated that average energy input is equal to ¼ of useful thermal energy (output). Further on in the paper the working principle of the heat pumps and their main parts are described
This paper presents the reliability assessment of the
southern part of Croatian transmission net... more This paper presents the reliability assessment of the southern part of Croatian transmission network and the influence of the wind farm on reliability indices. Croatian Electric Utility (HEP) Renewable Energy Sources with partner C.E.M.P. is developing wind farm in the region near town Knin. Wind farm will have installed capacity of 100 MW in the first phase. In the second phase additional 40 MW is planned to be installed. For the purpose of this paper, it was assumed that wind farm consist of the 50 turbine units, 2 MW each. Reliability assessment was performed, and reliability indices were computed for the case before and after construction of the wind farm. The reliability is analyzed using state enumeration method and NEPLAN software. Input data were obtained from annual reports of HEP TSO (Transmission System Operator) and statistic analysis of data was performed first. Since there are no statistical data for new cables and transformer stations that are constructed, input data for them were taken from the relevant literature. Probability of wind farm production level is taken from measured wind statistics. In reliability assessment Markov state space model of the wind generator, busbars, transformers, breakers and disconectors was used. Load is modeled at the output substation busbars with maximum active and reactive power. The simulations are performed in order to calculate reliability indices before and after the construction of wind farm. Conclusions and comments on the results are presented at the end of the paper.
Abstract—The paper presents a basic stochastic model of the influence of the failure statistics o... more Abstract—The paper presents a basic stochastic model of the influence of the failure statistics of the different wind turbine types and it’s components on the expected energy production. Based on the reliability performance surveys conducted in several European countries [1] the influence of the most unreliable component, the gearbox in particular has been examined taking into account the different behavior of the different wind turbine types (with and without gearbox) at different wind speeds with associated Weibull probability distribution. The load factors and expected energy not supplied has been calculated for two different commercial wind turbine types and compared.
The design and operation of a gasifier require an understanding of the gasification process
and ... more The design and operation of a gasifier require an understanding of the gasification process and design process of gasifier, primary energy source (biomass), and operating parameters influence on the performance of the plant. A good comprehension of the basic reactions is fundamental to the planning, design, operation, troubleshooting, and process improvement of a gasification plant. The design of a gasification plant includes the gasifier reactor as well as its auxiliary or support equipment. A typical biomass gasification plant design comprises gasifier reactor, biomass handling system, biomass feeding system, gas cleanup system and ash and solid residue removal system. As with most process plant equipment, the design of a gasifier may be divided into major phases such as process design and preliminary sizing, optimization of design and detailed mechanical design.
Two parts of this paper represent a contribution to implementation of a pump-storage hydroelectri... more Two parts of this paper represent a contribution to implementation of a pump-storage hydroelectric power plant stochastic model into a power plant system reliability model. Part II provides the method for determining the probability distribution of required pumping capacity of a pump-storage plant with natural inflow, and then the insertion of pump-storage hydro plants into the reliability model of the entire electrical energy production system. The inflow is thereby treated as a random variable, and stochastic modelling relies on the well-known method of constant and variable energy production. The model developed is suitable to create an additional decision-making criterion for studies related to expansion planning strategy of generating capacities in power systems. The stochastic models presented in this paper are illustrated by simple numerical examples
Two parts of this paper represent a contribution to the implementation of a pump-storage hydroele... more Two parts of this paper represent a contribution to the implementation of a pump-storage hydroelectric power plant stochastic model into a power plant system reliability model. After analysis of operation modes of such type of power plants, Part I gives an overview referring to the determination of the probability distribution of variable production when natural hydraulic inflow into the upper storage is exclusively used, the probability distribution of variable production from a pumped-storage drive, as well as the probability distribution of necessary energy of the plant with natural hydraulic inflow. The inflow is thereby treated as a random variable, and stochastic modeling relies on the well-known method of constant and variable energy production. The developed model is suitable for development of an additional determination criterion when it comes to making studies related to planning strategy of production capacities in the power system. The stochastic model presented in the paper is illustrated by a simple numerical example.
– Renewable energy sources have their share in the energy balance of almost every country, but no... more – Renewable energy sources have their share in the energy balance of almost every country, but not as much as they should compared to the given energy potential, although they allow the application of clean technologies and pollution reduction, reduce energy dependence on fossil fuel markets and enable the development of new technologies and supporting infrastructure that create new jobs. The primary interest of society as a whole is a rational energy use. With increasing population and growing demands for energy production and consumption, as well as the fact of the limited fossil fuel resources whose utilization leads to environmental pollution (the emergence of the greenhouse effect and global warming) there is an interest in increasing the participation of renewable energy sources (RES ) in energy sector. The total potential of RES in Vojvodina Province is 1293 ktoe/a, 34 ktoe/a of which (i.e. 2.6% of the total potential) lies in solar energy utilization. Possible thermal energy production from RES in Vojvodina Province is around 44.890 TJ/a, where 1400 TJ/a can be obtained from solar energy. Possible electricity production from RES in Vojvodina Province is around 2266 GWh/a, and solar energy has no participation in this production according to the Energy balance of Vojvodina Province. Solar Energy Potential in Pannonian Part of Serbia and Croatia Volume 3, Number 1, 2012 31 Review Branka Nakomčić-Smaragdakis Faculty of Technical Sciences, Department of Environmental Engineering and Occupational Safety Trg D. Obradovića 6, 21000 Novi Sad, Serbia nakomcic@uns.ac.rs Damir Šljivac J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering Kneza Trpimira 2b, Osijek, Croatia damir.sljivac@etfos.hr Vladimir Katić Faculty of Technical Sciences, Department of Power, Electronics and Telecommunication Engineering Trg D. Obradovića 6, 21000 Novi Sad, Serbia katav@uns.ac.rs Tijana Stajić Faculty of Technical Sciences, Department of Environmental Engineering and Occupational Safety Trg D. Obradovića 6, 21000 Novi Sad, Serbia tijanastajic@uns.ac.rs Zoran Čepić Faculty of Technical Sciences, Department of Environmental Engineering and Occupational Safety Trg D. Obradovića 6, 21000 Novi Sad, Serbia zorancepic@uns.ac.rs Danijel Topić J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering Kneza Trpimira 2b, Osijek, Croatia danijel.topic@etfos.hr Marko Vukobratović J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering Kneza Trpimira 2b, Osijek, Croatiaia marko.vukobratovic@etfos.hr32 International Journal of Electrical and Computer Engineering Systems Total possible energy production from RES in Croatia is estimated to 1046 ktoe/a in 2010, 12 ktoe/a of which (i.e. 1.2% of total possible potential) with expected growth to 2112 ktoe/a in 2020, 126 ktoe/a of which (i.e. 6.0% of total possible potential) and around 3502 ktoe/a in 2030, 331 ktoe/a of which (i.e. 9.4% of total possible potential). Due to the incentive scheme for RES electricity production in Croatia, this market is growing rapidly and the expected installed electrical RES capacities in Croatia in 2030 are 3055 MW mainly in wind power plants (2000 MW) due to the limited wind potentials mainly not located in Slavonia. Although there are no local data available in Slavonia, we can expect at least 50% of biomass and biogas power plants planned capacities in Croatia and around 20% of waste, geothermal and photovoltaic power plants summing up to over 1850 GWh/a with minimal participation of solar energy of not more than 3%. A share of RES in the energy balance of the country has its own energy, socio-economic and environmental benefits. RES provides application development and deployment of new technologies and supporting infrastructure, and therefore enables possibilities for new jobs, which directly contributes to economic development at local, regional and national level
The paper analyzes the consumption of all forms of energy in the city of Tuzla as well as the tot... more The paper analyzes the consumption of all forms of energy in the city of Tuzla as well as the total energy consumption. The first aspect of the analysis is a major problem of irrational consumption of energy in the city of Tuzla. There is an urgent need to reduce consumption of all forms of energy in the city of Tuzla in this way. Other aspects of all forms of energy consumption in the city of Tuzla are the huge energy intensity, environmental pollution, increasing the energy efficiency of new investments through affordable credit lines based on energy savings
The paper presents the way of modelling a subsystem of the power system from the power supply int... more The paper presents the way of modelling a subsystem of the power system from the power supply interruption consumer’s point. Results of reliability assessment indicate significant differences of results depending on the modelling and understanding of the input data. Valid reliability assessment can be performed only with excellent knowledge of the observed system, organization and rules. As an example of calculation, a simple transformer station 110 / x kV analysis is performed, considering the standard and improved model. The paper gives an overview of the different Markov models for simple transformer station and comparison of the results of reliability and availability. The improved model presented should contribute to better reliability and availability assessment results of observed subsystems.
There is constant research for solutions to reduce fossil fuel consumption and a way how to minim... more There is constant research for solutions to reduce fossil fuel consumption and a way how to minimize greenhouse gas emissions in the world. One possible solution is the usage of biogas for electricity and heat generation. The Republic of Croatia with a significant share of agriculture in the economy has an excellent basis for the energy production from biogas. This paper describes the history of the development of biogas in Europe and Croatia, concept of the biogas power plant, process of biogas production from manure collection, storage and processing, chemical processes that take place during the production of biogas, the building of a biogas power plant and the its parts with a brief description of work and purpose of each part of the plant.
The paper presents detailed comparison of solar energy potentials and cost-benefit analysis of in... more The paper presents detailed comparison of solar energy potentials and cost-benefit analysis of installing photovoltaic power systems in Pannonian parts of Croatia and Serbia. Feed-in tariff systems for incenting the electricity production from on-grid photovoltaic power systems and the resulting benefits on one side to the current investment and the projected life-time operation and maintenance cost on the other side, have been compared. PVGIS – PhotoVoltaic Geographical Information System have been used for data on solar irradiation and calculation of expected electricity production from PV systems with rated power up to 10 kW, 30 kW, 300 kW and over 300 kW (according to the different feed-in tariffs in Croatia). The results indicate substantial differences in PV markets development in Croatia and Serbia and the necessity to improve feed-in tariffs and legislation in Serbia in order to make the installation of PV systems feasible.
Paper presents cost – benefit analysis of biogas
CHP plant. It will cover the technical characte... more Paper presents cost – benefit analysis of biogas CHP plant. It will cover the technical characteristics of different biogas CHP plant with emphasis on energy efficiency and costs for biogas power plants. Comparison of electrical efficiency and overall (CHP) efficiency for different types of biogas power plants will also be presented
Paper deals with calculation and design of the heat
pumps that are used for purposes of heating ... more Paper deals with calculation and design of the heat pumps that are used for purposes of heating and cooling. Heat pumps are systems that draw heat from one source (earth, water, air or ambient) and transfer it to another. Their operation is described by Carnot circular process, in which thermal energy is taken from one body to working medium and then from a working medium to the heated body. Energy put in the process is equal to the energy needed for moving and compression of the working medium. Authors have calculated that average energy input is equal to ¼ of useful thermal energy (output). Further on in the paper the working principle of the heat pumps and their main parts are described
This paper presents the reliability assessment of the
southern part of Croatian transmission net... more This paper presents the reliability assessment of the southern part of Croatian transmission network and the influence of the wind farm on reliability indices. Croatian Electric Utility (HEP) Renewable Energy Sources with partner C.E.M.P. is developing wind farm in the region near town Knin. Wind farm will have installed capacity of 100 MW in the first phase. In the second phase additional 40 MW is planned to be installed. For the purpose of this paper, it was assumed that wind farm consist of the 50 turbine units, 2 MW each. Reliability assessment was performed, and reliability indices were computed for the case before and after construction of the wind farm. The reliability is analyzed using state enumeration method and NEPLAN software. Input data were obtained from annual reports of HEP TSO (Transmission System Operator) and statistic analysis of data was performed first. Since there are no statistical data for new cables and transformer stations that are constructed, input data for them were taken from the relevant literature. Probability of wind farm production level is taken from measured wind statistics. In reliability assessment Markov state space model of the wind generator, busbars, transformers, breakers and disconectors was used. Load is modeled at the output substation busbars with maximum active and reactive power. The simulations are performed in order to calculate reliability indices before and after the construction of wind farm. Conclusions and comments on the results are presented at the end of the paper.
Abstract—The paper presents a basic stochastic model of the influence of the failure statistics o... more Abstract—The paper presents a basic stochastic model of the influence of the failure statistics of the different wind turbine types and it’s components on the expected energy production. Based on the reliability performance surveys conducted in several European countries [1] the influence of the most unreliable component, the gearbox in particular has been examined taking into account the different behavior of the different wind turbine types (with and without gearbox) at different wind speeds with associated Weibull probability distribution. The load factors and expected energy not supplied has been calculated for two different commercial wind turbine types and compared.
The design and operation of a gasifier require an understanding of the gasification process
and ... more The design and operation of a gasifier require an understanding of the gasification process and design process of gasifier, primary energy source (biomass), and operating parameters influence on the performance of the plant. A good comprehension of the basic reactions is fundamental to the planning, design, operation, troubleshooting, and process improvement of a gasification plant. The design of a gasification plant includes the gasifier reactor as well as its auxiliary or support equipment. A typical biomass gasification plant design comprises gasifier reactor, biomass handling system, biomass feeding system, gas cleanup system and ash and solid residue removal system. As with most process plant equipment, the design of a gasifier may be divided into major phases such as process design and preliminary sizing, optimization of design and detailed mechanical design.
Two parts of this paper represent a contribution to implementation of a pump-storage hydroelectri... more Two parts of this paper represent a contribution to implementation of a pump-storage hydroelectric power plant stochastic model into a power plant system reliability model. Part II provides the method for determining the probability distribution of required pumping capacity of a pump-storage plant with natural inflow, and then the insertion of pump-storage hydro plants into the reliability model of the entire electrical energy production system. The inflow is thereby treated as a random variable, and stochastic modelling relies on the well-known method of constant and variable energy production. The model developed is suitable to create an additional decision-making criterion for studies related to expansion planning strategy of generating capacities in power systems. The stochastic models presented in this paper are illustrated by simple numerical examples
Two parts of this paper represent a contribution to the implementation of a pump-storage hydroele... more Two parts of this paper represent a contribution to the implementation of a pump-storage hydroelectric power plant stochastic model into a power plant system reliability model. After analysis of operation modes of such type of power plants, Part I gives an overview referring to the determination of the probability distribution of variable production when natural hydraulic inflow into the upper storage is exclusively used, the probability distribution of variable production from a pumped-storage drive, as well as the probability distribution of necessary energy of the plant with natural hydraulic inflow. The inflow is thereby treated as a random variable, and stochastic modeling relies on the well-known method of constant and variable energy production. The developed model is suitable for development of an additional determination criterion when it comes to making studies related to planning strategy of production capacities in the power system. The stochastic model presented in the paper is illustrated by a simple numerical example.
– Renewable energy sources have their share in the energy balance of almost every country, but no... more – Renewable energy sources have their share in the energy balance of almost every country, but not as much as they should compared to the given energy potential, although they allow the application of clean technologies and pollution reduction, reduce energy dependence on fossil fuel markets and enable the development of new technologies and supporting infrastructure that create new jobs. The primary interest of society as a whole is a rational energy use. With increasing population and growing demands for energy production and consumption, as well as the fact of the limited fossil fuel resources whose utilization leads to environmental pollution (the emergence of the greenhouse effect and global warming) there is an interest in increasing the participation of renewable energy sources (RES ) in energy sector. The total potential of RES in Vojvodina Province is 1293 ktoe/a, 34 ktoe/a of which (i.e. 2.6% of the total potential) lies in solar energy utilization. Possible thermal energy production from RES in Vojvodina Province is around 44.890 TJ/a, where 1400 TJ/a can be obtained from solar energy. Possible electricity production from RES in Vojvodina Province is around 2266 GWh/a, and solar energy has no participation in this production according to the Energy balance of Vojvodina Province. Solar Energy Potential in Pannonian Part of Serbia and Croatia Volume 3, Number 1, 2012 31 Review Branka Nakomčić-Smaragdakis Faculty of Technical Sciences, Department of Environmental Engineering and Occupational Safety Trg D. Obradovića 6, 21000 Novi Sad, Serbia nakomcic@uns.ac.rs Damir Šljivac J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering Kneza Trpimira 2b, Osijek, Croatia damir.sljivac@etfos.hr Vladimir Katić Faculty of Technical Sciences, Department of Power, Electronics and Telecommunication Engineering Trg D. Obradovića 6, 21000 Novi Sad, Serbia katav@uns.ac.rs Tijana Stajić Faculty of Technical Sciences, Department of Environmental Engineering and Occupational Safety Trg D. Obradovića 6, 21000 Novi Sad, Serbia tijanastajic@uns.ac.rs Zoran Čepić Faculty of Technical Sciences, Department of Environmental Engineering and Occupational Safety Trg D. Obradovića 6, 21000 Novi Sad, Serbia zorancepic@uns.ac.rs Danijel Topić J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering Kneza Trpimira 2b, Osijek, Croatia danijel.topic@etfos.hr Marko Vukobratović J. J. Strossmayer University of Osijek, Faculty of Electrical Engineering Kneza Trpimira 2b, Osijek, Croatiaia marko.vukobratovic@etfos.hr32 International Journal of Electrical and Computer Engineering Systems Total possible energy production from RES in Croatia is estimated to 1046 ktoe/a in 2010, 12 ktoe/a of which (i.e. 1.2% of total possible potential) with expected growth to 2112 ktoe/a in 2020, 126 ktoe/a of which (i.e. 6.0% of total possible potential) and around 3502 ktoe/a in 2030, 331 ktoe/a of which (i.e. 9.4% of total possible potential). Due to the incentive scheme for RES electricity production in Croatia, this market is growing rapidly and the expected installed electrical RES capacities in Croatia in 2030 are 3055 MW mainly in wind power plants (2000 MW) due to the limited wind potentials mainly not located in Slavonia. Although there are no local data available in Slavonia, we can expect at least 50% of biomass and biogas power plants planned capacities in Croatia and around 20% of waste, geothermal and photovoltaic power plants summing up to over 1850 GWh/a with minimal participation of solar energy of not more than 3%. A share of RES in the energy balance of the country has its own energy, socio-economic and environmental benefits. RES provides application development and deployment of new technologies and supporting infrastructure, and therefore enables possibilities for new jobs, which directly contributes to economic development at local, regional and national level
The paper analyzes the consumption of all forms of energy in the city of Tuzla as well as the tot... more The paper analyzes the consumption of all forms of energy in the city of Tuzla as well as the total energy consumption. The first aspect of the analysis is a major problem of irrational consumption of energy in the city of Tuzla. There is an urgent need to reduce consumption of all forms of energy in the city of Tuzla in this way. Other aspects of all forms of energy consumption in the city of Tuzla are the huge energy intensity, environmental pollution, increasing the energy efficiency of new investments through affordable credit lines based on energy savings
The paper presents the way of modelling a subsystem of the power system from the power supply int... more The paper presents the way of modelling a subsystem of the power system from the power supply interruption consumer’s point. Results of reliability assessment indicate significant differences of results depending on the modelling and understanding of the input data. Valid reliability assessment can be performed only with excellent knowledge of the observed system, organization and rules. As an example of calculation, a simple transformer station 110 / x kV analysis is performed, considering the standard and improved model. The paper gives an overview of the different Markov models for simple transformer station and comparison of the results of reliability and availability. The improved model presented should contribute to better reliability and availability assessment results of observed subsystems.
There is constant research for solutions to reduce fossil fuel consumption and a way how to minim... more There is constant research for solutions to reduce fossil fuel consumption and a way how to minimize greenhouse gas emissions in the world. One possible solution is the usage of biogas for electricity and heat generation. The Republic of Croatia with a significant share of agriculture in the economy has an excellent basis for the energy production from biogas. This paper describes the history of the development of biogas in Europe and Croatia, concept of the biogas power plant, process of biogas production from manure collection, storage and processing, chemical processes that take place during the production of biogas, the building of a biogas power plant and the its parts with a brief description of work and purpose of each part of the plant.
The paper presents detailed comparison of solar energy potentials and cost-benefit analysis of in... more The paper presents detailed comparison of solar energy potentials and cost-benefit analysis of installing photovoltaic power systems in Pannonian parts of Croatia and Serbia. Feed-in tariff systems for incenting the electricity production from on-grid photovoltaic power systems and the resulting benefits on one side to the current investment and the projected life-time operation and maintenance cost on the other side, have been compared. PVGIS – PhotoVoltaic Geographical Information System have been used for data on solar irradiation and calculation of expected electricity production from PV systems with rated power up to 10 kW, 30 kW, 300 kW and over 300 kW (according to the different feed-in tariffs in Croatia). The results indicate substantial differences in PV markets development in Croatia and Serbia and the necessity to improve feed-in tariffs and legislation in Serbia in order to make the installation of PV systems feasible.
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Papers by Danijel Topic
CHP plant. It will cover the technical characteristics of
different biogas CHP plant with emphasis on energy
efficiency and costs for biogas power plants. Comparison of
electrical efficiency and overall (CHP) efficiency for
different types of biogas power plants will also be presented
pumps that are used for purposes of heating and cooling. Heat
pumps are systems that draw heat from one source (earth, water,
air or ambient) and transfer it to another. Their operation is
described by Carnot circular process, in which thermal energy is
taken from one body to working medium and then from a
working medium to the heated body. Energy put in the process is
equal to the energy needed for moving and compression of the
working medium. Authors have calculated that average energy
input is equal to ¼ of useful thermal energy (output). Further on
in the paper the working principle of the heat pumps and their
main parts are described
southern part of Croatian transmission network and the
influence of the wind farm on reliability indices. Croatian
Electric Utility (HEP) Renewable Energy Sources with partner
C.E.M.P. is developing wind farm in the region near town Knin.
Wind farm will have installed capacity of 100 MW in the first
phase. In the second phase additional 40 MW is planned to be
installed. For the purpose of this paper, it was assumed that wind
farm consist of the 50 turbine units, 2 MW each. Reliability
assessment was performed, and reliability indices were computed
for the case before and after construction of the wind farm. The
reliability is analyzed using state enumeration method and
NEPLAN software. Input data were obtained from annual
reports of HEP TSO (Transmission System Operator) and
statistic analysis of data was performed first. Since there are no
statistical data for new cables and transformer stations that are
constructed, input data for them were taken from the relevant
literature. Probability of wind farm production level is taken
from measured wind statistics. In reliability assessment Markov
state space model of the wind generator, busbars, transformers,
breakers and disconectors was used. Load is modeled at the
output substation busbars with maximum active and reactive
power. The simulations are performed in order to calculate
reliability indices before and after the construction of wind farm.
Conclusions and comments on the results are presented at the
end of the paper.
and design process of gasifier, primary energy source (biomass), and operating
parameters influence on the performance of the plant. A good comprehension of the basic
reactions is fundamental to the planning, design, operation, troubleshooting, and process
improvement of a gasification plant. The design of a gasification plant includes the gasifier
reactor as well as its auxiliary or support equipment. A typical biomass gasification plant
design comprises gasifier reactor, biomass handling system, biomass feeding system, gas
cleanup system and ash and solid residue removal system. As with most process plant
equipment, the design of a gasifier may be divided into major phases such as process
design and preliminary sizing, optimization of design and detailed mechanical design.
reliability model. Part II provides the method for determining the probability distribution of required pumping capacity of a pump-storage plant with natural
inflow, and then the insertion of pump-storage hydro plants into the reliability model of the entire electrical energy production system. The inflow is thereby
treated as a random variable, and stochastic modelling relies on the well-known method of constant and variable energy production. The model developed is
suitable to create an additional decision-making criterion for studies related to expansion planning strategy of generating capacities in power systems. The
stochastic models presented in this paper are illustrated by simple numerical examples
reliability model. After analysis of operation modes of such type of power plants, Part I gives an overview referring to the determination of the probability
distribution of variable production when natural hydraulic inflow into the upper storage is exclusively used, the probability distribution of variable production
from a pumped-storage drive, as well as the probability distribution of necessary energy of the plant with natural hydraulic inflow. The inflow is thereby treated
as a random variable, and stochastic modeling relies on the well-known method of constant and variable energy production. The developed model is suitable for
development of an additional determination criterion when it comes to making studies related to planning strategy of production capacities in the power system.
The stochastic model presented in the paper is illustrated by a simple numerical example.
compared to the given energy potential, although they allow the application of clean technologies and pollution reduction, reduce energy
dependence on fossil fuel markets and enable the development of new technologies and supporting infrastructure that create new jobs. The
primary interest of society as a whole is a rational energy use. With increasing population and growing demands for energy production and
consumption, as well as the fact of the limited fossil fuel resources whose utilization leads to environmental pollution (the emergence of the
greenhouse effect and global warming) there is an interest in increasing the participation of renewable energy sources (RES ) in energy sector.
The total potential of RES in Vojvodina Province is 1293 ktoe/a, 34 ktoe/a of which (i.e. 2.6% of the total potential) lies in solar energy
utilization. Possible thermal energy production from RES in Vojvodina Province is around 44.890 TJ/a, where 1400 TJ/a can be obtained from
solar energy. Possible electricity production from RES in Vojvodina Province is around 2266 GWh/a, and solar energy has no participation in
this production according to the Energy balance of Vojvodina Province.
Solar Energy Potential in Pannonian
Part of Serbia and Croatia
Volume 3, Number 1, 2012 31
Review
Branka Nakomčić-Smaragdakis
Faculty of Technical Sciences,
Department of Environmental Engineering and Occupational Safety
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
nakomcic@uns.ac.rs
Damir Šljivac
J. J. Strossmayer University of Osijek,
Faculty of Electrical Engineering
Kneza Trpimira 2b, Osijek, Croatia
damir.sljivac@etfos.hr
Vladimir Katić
Faculty of Technical Sciences,
Department of Power, Electronics and Telecommunication Engineering
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
katav@uns.ac.rs
Tijana Stajić
Faculty of Technical Sciences,
Department of Environmental Engineering and Occupational Safety
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
tijanastajic@uns.ac.rs
Zoran Čepić
Faculty of Technical Sciences,
Department of Environmental Engineering and Occupational Safety
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
zorancepic@uns.ac.rs
Danijel Topić
J. J. Strossmayer University of Osijek,
Faculty of Electrical Engineering
Kneza Trpimira 2b, Osijek, Croatia
danijel.topic@etfos.hr
Marko Vukobratović
J. J. Strossmayer University of Osijek,
Faculty of Electrical Engineering
Kneza Trpimira 2b, Osijek, Croatiaia
marko.vukobratovic@etfos.hr32 International Journal of Electrical and Computer Engineering Systems
Total possible energy production from RES in Croatia is estimated to 1046 ktoe/a in 2010, 12 ktoe/a of which (i.e. 1.2% of total possible
potential) with expected growth to 2112 ktoe/a in 2020, 126 ktoe/a of which (i.e. 6.0% of total possible potential) and around 3502 ktoe/a
in 2030, 331 ktoe/a of which (i.e. 9.4% of total possible potential). Due to the incentive scheme for RES electricity production in Croatia, this
market is growing rapidly and the expected installed electrical RES capacities in Croatia in 2030 are 3055 MW mainly in wind power plants
(2000 MW) due to the limited wind potentials mainly not located in Slavonia. Although there are no local data available in Slavonia, we
can expect at least 50% of biomass and biogas power plants planned capacities in Croatia and around 20% of waste, geothermal and
photovoltaic power plants summing up to over 1850 GWh/a with minimal participation of solar energy of not more than 3%.
A share of RES in the energy balance of the country has its own energy, socio-economic and environmental benefits. RES provides application
development and deployment of new technologies and supporting infrastructure, and therefore enables possibilities for new jobs, which
directly contributes to economic development at local, regional and national level
problem of irrational consumption of energy in the city of Tuzla. There is an urgent need to reduce consumption of all forms of energy in the city of Tuzla in this
way. Other aspects of all forms of energy consumption in the city of Tuzla are the huge energy intensity, environmental pollution, increasing the energy
efficiency of new investments through affordable credit lines based on energy savings
assessment indicate significant differences of results depending on the modelling and understanding of the input data. Valid reliability assessment can be
performed only with excellent knowledge of the observed system, organization and rules. As an example of calculation, a simple transformer station 110 /
x kV analysis is performed, considering the standard and improved model. The paper gives an overview of the different Markov models for simple
transformer station and comparison of the results of reliability and availability. The improved model presented should contribute to better reliability and
availability assessment results of observed subsystems.
CHP plant. It will cover the technical characteristics of
different biogas CHP plant with emphasis on energy
efficiency and costs for biogas power plants. Comparison of
electrical efficiency and overall (CHP) efficiency for
different types of biogas power plants will also be presented
pumps that are used for purposes of heating and cooling. Heat
pumps are systems that draw heat from one source (earth, water,
air or ambient) and transfer it to another. Their operation is
described by Carnot circular process, in which thermal energy is
taken from one body to working medium and then from a
working medium to the heated body. Energy put in the process is
equal to the energy needed for moving and compression of the
working medium. Authors have calculated that average energy
input is equal to ¼ of useful thermal energy (output). Further on
in the paper the working principle of the heat pumps and their
main parts are described
southern part of Croatian transmission network and the
influence of the wind farm on reliability indices. Croatian
Electric Utility (HEP) Renewable Energy Sources with partner
C.E.M.P. is developing wind farm in the region near town Knin.
Wind farm will have installed capacity of 100 MW in the first
phase. In the second phase additional 40 MW is planned to be
installed. For the purpose of this paper, it was assumed that wind
farm consist of the 50 turbine units, 2 MW each. Reliability
assessment was performed, and reliability indices were computed
for the case before and after construction of the wind farm. The
reliability is analyzed using state enumeration method and
NEPLAN software. Input data were obtained from annual
reports of HEP TSO (Transmission System Operator) and
statistic analysis of data was performed first. Since there are no
statistical data for new cables and transformer stations that are
constructed, input data for them were taken from the relevant
literature. Probability of wind farm production level is taken
from measured wind statistics. In reliability assessment Markov
state space model of the wind generator, busbars, transformers,
breakers and disconectors was used. Load is modeled at the
output substation busbars with maximum active and reactive
power. The simulations are performed in order to calculate
reliability indices before and after the construction of wind farm.
Conclusions and comments on the results are presented at the
end of the paper.
and design process of gasifier, primary energy source (biomass), and operating
parameters influence on the performance of the plant. A good comprehension of the basic
reactions is fundamental to the planning, design, operation, troubleshooting, and process
improvement of a gasification plant. The design of a gasification plant includes the gasifier
reactor as well as its auxiliary or support equipment. A typical biomass gasification plant
design comprises gasifier reactor, biomass handling system, biomass feeding system, gas
cleanup system and ash and solid residue removal system. As with most process plant
equipment, the design of a gasifier may be divided into major phases such as process
design and preliminary sizing, optimization of design and detailed mechanical design.
reliability model. Part II provides the method for determining the probability distribution of required pumping capacity of a pump-storage plant with natural
inflow, and then the insertion of pump-storage hydro plants into the reliability model of the entire electrical energy production system. The inflow is thereby
treated as a random variable, and stochastic modelling relies on the well-known method of constant and variable energy production. The model developed is
suitable to create an additional decision-making criterion for studies related to expansion planning strategy of generating capacities in power systems. The
stochastic models presented in this paper are illustrated by simple numerical examples
reliability model. After analysis of operation modes of such type of power plants, Part I gives an overview referring to the determination of the probability
distribution of variable production when natural hydraulic inflow into the upper storage is exclusively used, the probability distribution of variable production
from a pumped-storage drive, as well as the probability distribution of necessary energy of the plant with natural hydraulic inflow. The inflow is thereby treated
as a random variable, and stochastic modeling relies on the well-known method of constant and variable energy production. The developed model is suitable for
development of an additional determination criterion when it comes to making studies related to planning strategy of production capacities in the power system.
The stochastic model presented in the paper is illustrated by a simple numerical example.
compared to the given energy potential, although they allow the application of clean technologies and pollution reduction, reduce energy
dependence on fossil fuel markets and enable the development of new technologies and supporting infrastructure that create new jobs. The
primary interest of society as a whole is a rational energy use. With increasing population and growing demands for energy production and
consumption, as well as the fact of the limited fossil fuel resources whose utilization leads to environmental pollution (the emergence of the
greenhouse effect and global warming) there is an interest in increasing the participation of renewable energy sources (RES ) in energy sector.
The total potential of RES in Vojvodina Province is 1293 ktoe/a, 34 ktoe/a of which (i.e. 2.6% of the total potential) lies in solar energy
utilization. Possible thermal energy production from RES in Vojvodina Province is around 44.890 TJ/a, where 1400 TJ/a can be obtained from
solar energy. Possible electricity production from RES in Vojvodina Province is around 2266 GWh/a, and solar energy has no participation in
this production according to the Energy balance of Vojvodina Province.
Solar Energy Potential in Pannonian
Part of Serbia and Croatia
Volume 3, Number 1, 2012 31
Review
Branka Nakomčić-Smaragdakis
Faculty of Technical Sciences,
Department of Environmental Engineering and Occupational Safety
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
nakomcic@uns.ac.rs
Damir Šljivac
J. J. Strossmayer University of Osijek,
Faculty of Electrical Engineering
Kneza Trpimira 2b, Osijek, Croatia
damir.sljivac@etfos.hr
Vladimir Katić
Faculty of Technical Sciences,
Department of Power, Electronics and Telecommunication Engineering
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
katav@uns.ac.rs
Tijana Stajić
Faculty of Technical Sciences,
Department of Environmental Engineering and Occupational Safety
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
tijanastajic@uns.ac.rs
Zoran Čepić
Faculty of Technical Sciences,
Department of Environmental Engineering and Occupational Safety
Trg D. Obradovića 6, 21000 Novi Sad, Serbia
zorancepic@uns.ac.rs
Danijel Topić
J. J. Strossmayer University of Osijek,
Faculty of Electrical Engineering
Kneza Trpimira 2b, Osijek, Croatia
danijel.topic@etfos.hr
Marko Vukobratović
J. J. Strossmayer University of Osijek,
Faculty of Electrical Engineering
Kneza Trpimira 2b, Osijek, Croatiaia
marko.vukobratovic@etfos.hr32 International Journal of Electrical and Computer Engineering Systems
Total possible energy production from RES in Croatia is estimated to 1046 ktoe/a in 2010, 12 ktoe/a of which (i.e. 1.2% of total possible
potential) with expected growth to 2112 ktoe/a in 2020, 126 ktoe/a of which (i.e. 6.0% of total possible potential) and around 3502 ktoe/a
in 2030, 331 ktoe/a of which (i.e. 9.4% of total possible potential). Due to the incentive scheme for RES electricity production in Croatia, this
market is growing rapidly and the expected installed electrical RES capacities in Croatia in 2030 are 3055 MW mainly in wind power plants
(2000 MW) due to the limited wind potentials mainly not located in Slavonia. Although there are no local data available in Slavonia, we
can expect at least 50% of biomass and biogas power plants planned capacities in Croatia and around 20% of waste, geothermal and
photovoltaic power plants summing up to over 1850 GWh/a with minimal participation of solar energy of not more than 3%.
A share of RES in the energy balance of the country has its own energy, socio-economic and environmental benefits. RES provides application
development and deployment of new technologies and supporting infrastructure, and therefore enables possibilities for new jobs, which
directly contributes to economic development at local, regional and national level
problem of irrational consumption of energy in the city of Tuzla. There is an urgent need to reduce consumption of all forms of energy in the city of Tuzla in this
way. Other aspects of all forms of energy consumption in the city of Tuzla are the huge energy intensity, environmental pollution, increasing the energy
efficiency of new investments through affordable credit lines based on energy savings
assessment indicate significant differences of results depending on the modelling and understanding of the input data. Valid reliability assessment can be
performed only with excellent knowledge of the observed system, organization and rules. As an example of calculation, a simple transformer station 110 /
x kV analysis is performed, considering the standard and improved model. The paper gives an overview of the different Markov models for simple
transformer station and comparison of the results of reliability and availability. The improved model presented should contribute to better reliability and
availability assessment results of observed subsystems.