Abstract of the thesis RESEARCH ON DEVELOPMENT OF HYBRID WIND HYDRO POWER PLANTS

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1 Investeşte în oameni! FONDUL SOCIAL EUROPEAN Programul Operaţional Sectorial Dezvoltarea Resurselor Umane Axa prioritară: 1 Educaţia şi formarea profesională în sprijinul creşterii economice şi dezvoltării societăţii bazate pe cunoaştere Domeniul major de intervenţie: 1.5 Programe doctorale și postdoctorale în sprijinul cercetării Titlul proiectului: Proiect de dezvoltare a studiilor de doctorat în tehnologii avansate- PRODOC Numarul de identificare al contractului: POSDRU 6/1.5/S/5 Beneficiar: Universitatea Tehnică din Cluj-Napoca Abstract of the thesis RESEARCH ON DEVELOPMENT OF HYBRID WIND HYDRO POWER PLANTS 1.1 Thesis opportunity This thesis aims to provide economic solutions for the supply of electricity to isolated communities without access to the National Energy System. The most promising source of renewable energy for remote locations is wind. This technology has proven to be economically viable for the locations where conditions are favorable (especially in mountainous areas, where there are long periods of time with high wind speeds), and most often, the price of production is comparable to the price of energy obtained from conventional sources or even less than this one. Wind energy has a big disadvantage: variability of wind power. In order to compensate the variability of wind power it is not economic to use batteries or other storage methods because they are expensive. Such a facility can be called hybrid system, because it combines two sources of power: one wind and one hydro. This notion of hybrid system has become increasingly common in the literature with the development of renewable energy technologies. The entire civilization is based on current production, transmission and conversion of electrical energy. Electrical systems are involved in all aspects of modern life. Perhaps it ll be a difficult effort of imagination for humankind to realize how life was going a hundred and more years ago, when this form of energy was not involved in human life.

2 The disappearance of consumed electricity and electrical systems dedicated to make it usable will produce a collapse in the evolution of human society. But the development and evolution of human society over the past 100 years, based on cheap energy, is nearing completion. There are two main causes: depletion of fossil fuels (and therefore cheaper) and pollution that increases with their more intensive use due to population growth. We are approaching a critical point of intersection curves of decreasing resources and increasing pollution, scheduled to take place in about years. Consequently production processes and the way of life based on intensive and inefficient energy consumption, and hence the electric energy, must be stopped and replaced. In this context the theme of research on using wind power sources has a highly impact. One of the current global concerns in the field of power generation systems is the introduction of renewable energy as the main potential for electricity generation, and as an alternative to existing solutions. Diversification of primary energy sources is one of the most competitive solutions in this area, and a system that uses a combination of different resources, has the stability advantage. Renewable energy can help in meeting priority needs of current electricity and heating in disadvantaged rural areas and other isolated communities located far from public electricity network. Renewable electricity sources are suitable for the current electricity needs in disadvantaged rural areas and in remote locations. The advantages of renewable sources are: Less greenhouse gas emissions; Less waste; Reducing energy dependence; Promote green technologies; New opportunities for business. In Romania there are still many households, small communities, etc. (located usually away from the grid and inaccessible areas) that do not have electricity. Thus, the interest of investors and users are moving largely to small-scale applications. Because 2

3 energy from renewable sources is an alternative to fossil fuels, the demand for renewable energy technologies has increased as for reasons of reducing emissions of greenhouse effect gases and other reasons such as: execution time for the production of energy relatively low (for wind power plants and photovoltaic power plants) ; ease and speed of the decommissioning of such facilities that are unuseful (the installations of renewable energy sources are generally modular feature that helps to improve operational performances and reduces maintenance costs on installation). If you want to supply a group of households or small isolated communities located far from the public electricity with renewable energy sources we must take account of the following conditions: operating regimes correlated with working regimes, relatively different for distinct consumers; optimal level of different consumers (load circuit optimization); production / consumption graphic; coordination of relations between different consumers; dissipation problem and, consequently, reducing individually interest on different aspects of its operation. This thesis aims to determine the best solutions and technical conditions for construction and operation of power plants producing electricity from renewable sources in the specific conditions mentioned above. From the above list the most promising source of renewable energy for remote locations seems to be the wind resource. This technology has proven to be economically viable for the locations where conditions are favorable (especially in the mountainous areas, where there are long periods of time with wind speeds), and most often the price of production from renewable sources is comparable to the price of energy obtained from conventional sources or even less than this one [Finta, 2003]. In order to compensate the variability of wind power it is not economic to use batteries or other storage methods because they are expensive. Integration of wind energy in the grid system represents an alternative to ensure continuity and sustainability of wind resources. Integration of renewable energy systems 3

4 like wind power is a difficult problem. Using wind turbines is a serious option for achieving these objectives. However, wind energy has some disadvantages: has a low energy density (a 10 MW wind farm occupies an area of several hectares where a 10 MW power station occupies a much smaller area); electricity produced from renewable energy has a variable character because of the variable wind speed; is diluted, meaning that it has a low concentration per unit area; areas with high wind potential are located far from populated areas and requires the transport of electricity; aesthetic pollution of the environment; relatively high cost of electricity. Among these disadvantages the most unpleasant character of wind is it s variability. Power generated by a wind turbine is proportional with the cube of wind speed and so electric power is even more variable and is essential a means of energy storage. It is clear that such a source of electricity must be supplemented by an energy source compensation that can be started quickly when the wind stops and with an energy storage system for periods of calm winds. Until the discovery of high capacity batteries and low price it is important to study the possibilities of energy storage in potential energy of water, in hydroelectric pumping storage systems. This thesis studied the possibility of storing wind energy as potential energy of water in pumping stations. This thesis aims to study the efficiency of using the storage capacity of hydro power plant to store the wind energy in the form of hydro-energy of water, to supply electricity to isolated communities located relatively far from the public electricity network. Such a system can be called hybrid wind - hydro plants because it combines two sources of electrical energy: wind and hydroelectric power. This notion of SH has become increasingly common in the literature with the development of renewable energy technologies. 4

5 It should be noted that the presence of the pumped storage hydro power plants with a potential hydropower does not involve only the presence of water sources: river, natural lake or pond. Also through this system by pumping hydro storage is managed with better water by capturing rainwater and melting snow that coming through. Thus, this water can be used both for household after filtration or for irrigation in agriculture or fisheries or can be used by the hydroelectric pump. The thesis addresses the use of CHHE to supply electricity to isolated communities in Romania, especially in remote rural areas located far away from the public electricity network. In this locations there a re favorable conditions for implementing a hybrid wind-hydro power plant because there is an important wind energy potential on the tops of hills, due to the hill effect and the presence of a lake or stream, even without an important hydroelectric potential to achieve the construction of an artificial lake. Due to the increasing electricity demand and population growth, the transition from fossil fuels to renewable energy is not an option but it has become a necessity. The title thesis results from the current trend of obtaining "clean" electricity from renewable wind and hydro power Thesis Objectives This thesis studied the possibility of storing wind energy as potential energy of water in pumping stations in order to use the energy to supply consumers located in isolated locations far from the public electricity network. The methodology of designing an autonomous hybrid wind-hydro power plant involves finding optimal values for: The installed wind turbine nominal power; Pumps power and hydraulic pump power; Superior tank capacity and possibly inferior tank capacity. The thesis aims to: Maximize use of renewable energy sources (RES) for supplying consumers that are isolated located; Minimizing the cost of electric energy based on RES in isolated locations far from public electricity network; 5

6 Improvement of isolated electricity network security; Reduces consumption of fossil fuels and their negative effects on the environment for remote power systems Structure of the thesis This thesis is divided into five chapters as follows: The second chapter presents the main solutions of hybrid wind-hydro power plant and examples of their use to supply electricity consumers located in isolated locations, including energy storage means to compensate the variability of wind power. Also, it is presented the proposed structure of hybrid wind hydro power plant. Chapter three presents the methodology developed for designing autonomous wind-hydro power plant. Further, this method will be applied on a case study for Mărişel location. Also, a dynamic modeling with MATLAB / SIMULINK is presented. This model presents experimental measurements whose results confirm the design methodology developed. The fourth chapter presents the designed and built model of hybrid wind hydro power plant. For the studied model, an analysis with Homer was performed. Finally, chapter five presents the conclusions of this research and suggestions and possibilities for further research in this area. There are also presents the author's main personal contributions. Using a hybrid wind - hydro system has clear advantages for the power supply housing in isolated locations or group housing with limited power consumption, and represents an alternative solution to connecting to the national energy system, especially where this it is not even possible. Hybrid wind -hydro systems are useful for powering remote and isolated villages, and also the upper lake can be used for drinking water, irrigation water in agriculture and fish growth. Technical and economic calculation made on the solution designed in the case study shows an economic advantage of using renewable energy to the solution of using electricity to supply isolated communities with diesel groups. The proposed hybrid system includes a wind subsystem which is connected to the physical hydro model in order to form the physical model of the hybrid wind hydro 6

7 power plant. The load linked to the output inverter module consists of hydro pumps, and in this way we can achieve the physical model of the hybrid wind hydro power plant. The experiments conducted on the physical model demonstrates the opportunity to use wind power even in locations without a significant wind energy potential if the system is complete with a viable energy storage power system. It can be noted that technical and economic analysis indicates that for many situations the solution of electrification from renewable sources (RES) can be competitive or even cheaper than other conventional solutions: network connection or sets. 1.6 Author s contributions The author's main contribution is to demonstrate the possibility of storing wind energy as potential energy in water pumping stations by hydroelectric reservoir (CHEAP) to supply electricity to consumers located in isolated locations away from the public electric network. In the thesis has been carried out a bibliographic research on the technologies used worldwide for supplying electricity to consumers located in isolated locations with an emphasis on hybrid power plants in general and hybrid wind hydro in particular. Also, there were studied particularly, the hybrid wind hydro solutions already implemented or It was developed a design methodology for hybrid wind hydro systems for supplying electricity to electric consumers in isolated communities, located far from the public electricity network. The designed methodology was applied on a case study taking into account a real location. Technical and economic analysis conducted validated the applied methodology. Also, I developed a physical model of low-power hybrid wind hydro system, functional and useful for teachers and students and for doctoral research. It was performed a dynamic computer simulation on the solution designed and built, and an economic analysis was conducted on the small physical model. There were conducted experiments in the laboratory to validate the results obtained from simulations for the case study or for the small-scale physical model. It was designed a monitoring and control system for hybrid wind-hydro power plant, and was developed a small monitoring system for the consumed on different components of the physical model. 7

8 This thesis address only the solution of hybrid wind-hydro system with independent operation of wind pumping system, when there is wind and respectively of the hydro power when there is electric charge. For future research should address direct supply to consumers when there is wind and electric charge, a situation which would increase the overall efficiency of energy conversion of the hybrid power plant. Also, research must continue to carry out a complex monitoring system miniscada to ensure autonomous operation of the hybrid power system without any supervision. 8