Η παρούσα διπλωματική εργασία κάνει μια ανασκόπηση στην ενεργειακή κατάσταση του πλανήτη και της Ελλάδας. Παρουσιάζει τις εναλλακτικές-ανανεώσιμες μορφές ενέργειας παραγωγής ηλεκτρισμού. Στη συνέχεια, αναλύει τον άνεμο, τα χαρακτηριστικά μεγέθη του, την αιολική ενέργεια, και τις προοπτικές της εγχώρια. Βλέπουμε αναλυτικά τον ανεμοκινητήρα, τους διαφορετικούς τύπους του και τη λειτουργία του. Και καταλήγουμε στο να καθορίσουμε τους τρόπους αξιολόγησης μιας αιολικής εγκατάστασης, εκφράζουμε μαθηματικά τις οικονομικές σχέσεις και παραθέτουμε μια εφαρμογή αιολικής εγκατάστασης που αναλύεται με τα παραπάνω. Τέλος, αναφερόμαστε στο νομοθετικό πλαίσιο αν και ρευστό από έτος σε έτος και στην ισχύουσα διαδικασία εγκατάστασης ενός αιολικού πάρκου. / The present dissertation gives a general review of the situation of energy of the planet and Greece. It presents the alternative-renewable forms of energy for the production of electricity. Afterwards, it analyses the wind, its characteristic sizes, the wind power and its domestic perspectives. We can see in detail the wind engine , its various types and its function. Furthermore, we end up defining the ways evaluating of a wind installation, we express mathematically the financial relations and we not only cite an application of a wind installation which is analysed with the above mentioned ways but we also present the easiest analysis through the computer. Finally, we refer to the legislative scope even though it is unstable from year to year and to the procedure of installation of a wind park which is in effect.

Sediment erosion is a major challenge for run-of-river power plants, especially during flood periods. Due to the high content of hard minerals such as quartz and feldspar carried in the river, substantial damage is observed on the turbine components. Material is gradually removed, thus the efficiency of the turbine decreases and the operating time of the turbine reduces. Hydro power plants situated in areas with high sediment concentration suffer under hard conditions, where turbine components could be worn out after only a short period of three months. This short life expectation causes trouble for energy production since the replacement of new turbine parts is a time consuming and costly procedure. It is desirable to design a Francis runner which will withstand sediment erosion better than the traditional designs. The literature states that an expression for erosion is velocity to the power of three. By reducing the relative velocities in the runner by 10%, the erosion will decrease almost 30%. The objective is to improve the design of a Francis turbine which operates in rivers with high sediment concentration, by looking at the design parameters in order to reduce erosion wear. A Francis turbine design tool was developed to accomplish the parameter study. In the search for an optimized Francis runner, several design proposals were compared against a reference design by evaluating the turbine’s performance. The hydraulic flow conditions and the prediction of erosion on the turbine components are simulated by analyzing the models with a Computational Fluid Dynamic (CFD) tool. A Fluid Structure Interaction (FSI) analysis ensures that the structural integrity of the design is within a desired value. Results from this research show that it is feasible to design a runner with an extended lifetime, without affecting the main dimensions and hydraulic efficiency.

Wind energy is a continuous, clean source of energy that can be harnessed for electricity generation or water pumping. The geographic location of Mozambique, and the long coastline renders the country a good wind energy potential that could potentially be exploited for water pumping or electrical power systems that have social and economic benefits and thereby contribute to a reduction in unsustainable practices of wood biomass burning which is the main source of energy in rural villages and high density suburbs of the main cities of the country. This study is focused on evaluating the potential of harnessing wind energy for electrical power generation in Mozambique using the Wind Atlas Analysis and Application Programme (WAsP) model. The study characterises wind speed patterns and wind frequency distributions at selected meteorological stations based on hourly observations, and models the available wind energy in coastal and interior areas. Meteorological parameters such as wind speed data from nearby meteorological stations and wind turbine characteristics were used as inputs into the model. To effectively harness wind energy, mean annual wind speeds should at least be 3 ms-1. For this reason only sites satisfying this criterion were selected. The spatial selection criteria considered a fair distribution of candidate sites such that coastal areas of the southern, northern and the interior Niassa and Nampula provinces were covered. The results of the WAsP model simulations, indicate that there is sufficient wind energy resource in both interior and coastal areas, which varies with height a.g.l., and that can be exploited for pumping water and generating electricity in small or medium electrical power systems, particularly the coastal areas of Ponta de Ouro, Mavelane, and Tofinho where the mean annual wind speed is above 5.0 ms-1 at the 10 m level and about 8.0 ms-1 at the highest levels (50 - 60 m a.g.l.) and interior area of Lichinga (mean annual wind speed of about 6 ms-1 at the same highest levels). The lowest wind energy potential (mean annual wind speed of about 4.0 ms-1) is found in the Nampula area. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

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