Design, Modelling and Control of a Grid-connected Hybrid Pv-wind System (Case Study of Adrar)

Abstract

"Most countries are planning to increase their power supply capacities and diversify resources for electricity generation. In Africa, ambitious objectives in this regard, have been set by many countries. Large scale renewable energy power plants are primordial for increasing the renewable energy share in the total energy mix, though they are rare in African countries except for the case of hydropower. In February 2015, the Algerian government adopted an ambitious Renewable Energy Program planning the installation of 22 GW of Renewable Energy by 2030 [1]. However, the major challenge to the development of such programs are the subsidized electricity prices in the country, these low prices result in one of the highest irrational energy consumptions in the continent. Due to its semi-arid to arid climate, the country witnesses very high power-demand in summer, caused by accumulated cooling loads. The national grid often struggles to deliver such power resulting in electricity outages and blackouts, especially in the southern part of the country. In the present thesis, a general review is conducted on different renewable energy resources in Algeria, the solar and wind energy potential in Adrar is investigated along with the climate conditions. A state-of-the-art review on photovoltaic, wind and hybrid energy systems is carried out. Technologies used in each of the systems are revealed and the control techniques employed in the different components of the systems are also presented. The city of Adrar, situated in the south-west of Algeria, was chosen as the case study of this work because of the available solar and wind energy potential. Another reason for this choice is the power outages and poor performance of the grid noticed during the summer season. Therefore, to tackle overload problems and contribute to the Algerian Renewable Energy Program, a hybrid grid-connected PV-wind system has been designed and modelled in MATLAB/SIMULINK. The control mechanisms for the different components of the system have been studied and modelled, and the sizing of the system was based on the available potential of solar and wind energies and on the electricity demand of the city for two critical seasons (Winter and Summer). The performance of the implemented control techniques proved to be robust, and the modelled system was simulated in SIMULINK for the months of January and August. METEONORM software was used to provide the weather file for Adrar, which contains hourly data for solar irradiation, wind speeds and temperature. It was found that the designed system contributes to the performance of the grid by a minimum of 10% and a maximum of 200%, depending on the available potential. Moreover, an economic and environmental analysis of the system was undertaken in HOMER software. Although, the overall cost of the system was evaluated at $42.1 million, the levelized cost of electricity (LCOE) was found as low as 0.084 $/kWh due to the feed in tariffs policy adopted in the country, thus the system proved to be very profitable. Furthermore, the hybrid system helped mitigating global warming and climate change by reducing a significant amount of greenhouse gas emissions, that would rather be emitted by conventional natural gas power plants."