A review of optimum sizing of hybrid PV–Wind renewable energy systems in oman

Abstract

Renewable energy hybrid power systems have been proven through their ability to address the limitations of single renewable energy system in terms of power efficiency, stability, and reliability while operating at minimum cost. In this regards many research and practical experiences have been done. The present paper reviews the different hybrid PV–Wind renewable energy hybrid systems used for electrical power generations. Different criteria of sizing the different system components of hybrid renewable energy power plant at the most preferable logistical environmental and economical considerations have been discussed. Also, the paper discussed some of the optimization approaches which are used to compare the energy production cost and performance of different hybrid system configurations using simulation techniques. Based on the fact that, potential of the wind and solar energy is not equal in Oman, this paper will discuss the optimum sizing process of two proposed hybrid PV–Wind plants in Oman.

Introduction

Hybrid Renewable Energy Systems (HRES) are defined as an electric energy system which is made up of one renewable source and one or more sources. These sources could be conventional or renewable or mixed, that works in off-grid (standalone) or grid connected mode [1]. The main feature of hybrid renewable energy systems is to combine two or more renewable power generation and so they can address emissions, reliability, efficiency, and economical limitations of single renewable energy source [2].

HRES are becoming popular for standalone power generation in isolated area due to the improvement and efficiency increment in renewable energy technologies and power electronic converters [3]. Based on the availability of the natural local resources, there are some advantages of the hybrid system. Higher environmental protection, green house gas emission, especially CO₂ and reduction in other pollutants emissions is expected due to the lower consumption of fuel. The cost of solar and wind energy can be competitive with nuclear and the diversity and security of natural resources who are free, abundant, and inexhaustible [4]. Most of these appliances can be easily installed and they are rapidly deployed. Financially, the costs are predictable and not influenced by fuel price fluctuations [5], [6], [7], [8]. However, because of the photovoltaic (PV)–Wind changeable nature and dependence on climatic changes and weather, a common drawback to PV and wind power generations is that both would have to be oversized to make their standalone systems reliable for the times when neither system is producing enough electric power to satisfy the load [9].

Many areas are concerned with the applications of the HRES. Researches [1], [10] have focused on the performance analysis of demonstration systems and the development of efficient power converters, such as the maximum power point trackers and bi-directional inverters [11], [12]. Other researches focused on the battery management units and the storages devices [6].

In the last decade, various HRES have been installed in different countries, resulting in the development of systems that can compete with conventional, fuel based remote area power supplies [13]. However, there are several combinations of hybrid energy system which mainly depend on the natural available resources, the wind or the solar energy practically represents one source of the hybrid renewable energy systems.

With the advance development of the hybrid PV–Wind systems for electrical power generation, the target to achieve reliable and efficient performance became complicated task. So that there is a need to select and configure the optimum sizing of all components in order to obtain the minimum capital investment while maintaining system reliability to satisfy the load [14], [15]. This paper summarized three common used sizing methods for hybrid PV–Wind systems. Moreover, the paper will discuss some optimization techniques of the PV–Wind HRES. These techniques are used to compare the technical performance and cost of energy for different system configurations using simulation approaches.

The objectives of this study are to investigate the hybrid solar-wind systems in Oman and optimum design techniques used. This work will focus on the standalone (off-grid) PV–Wind HRES as both solar and wind has the highest potential in Oman compared to the other renewable energy sources [16], [17]. Revision and discussion of the related studies in literature are presented. Two case studies will be discussed as a practical implementation of the right sizing and optimization of the Masirah and Al-Halaniyat Islands proposed HRES. Finally, discussion of the current hybrid systems in Oman and possibilities to install new systems is recommended.