A comprehensive review of wind resource assessment

Abstract

A minor deviation in wind speed causes large deviation in the output power of wind turbine because of cubic bond association between these two parameters. Therefore, a precise assessment of wind resource over any site is considered of paramount significance. The investigations associated with the wind resource assessment have been proved of immense help for installation of different wind energy technologies such as nano, micro, small, medium, and large scale for wind energy generation. In order to provide a detailed information regarding the research in wind resource assessment a comprehensive literature review encompassing the different techniques, methodologies involved in development of wind power projects, and uncertainties associated with wind resource assessment as well as the preliminary assessment methodologies have been presented in this work. The advanced computational models namely wind atlas analysis and program, WindPro, computational fluid dynamics, and geographical information system are most frequently used software tools for mapping, modelling and annual energy estimation for a single or multiple wind turbines by considering the local conditions such as topography, surrounding obstacles, orography, and surface roughness based on the on-site measurements for a particular site. In addition, the statistical methods for short and long term data analysis, vertical wind speed profile, numerical weather prediction models, optimization of existing wind resource, and scope of hybrid wind energy systems have been delineated in this paper. Furthermore, current review presents a complete approach with reference to all the facets of the present status of research in the area of wind resource assessment worldwide.

Introduction

The energy sector assumes critical importance in view of ever increasing demand requiring huge investments. There has been a sturdy association between commercial activities and accessibility to the energy resources depending on the historical data. Electricity generation is a major driving force for the financial progress of developing economies like India, which has been viewing a phenomenal industrial progress. The generation of electricity by fossil fuels has been one of the prominent activity in such fuel based economies throughout the world, however such type of electricity generation imposes an adverse threat to the environment due to pollution, in the form of greenhouse gases emissions in the environment, thereby causing problems like global warming, acid rains, and climate change [1]. In global context, electricity generation by renewable energy applications show that the major contribution is from hydro and wind resource whereas a small portion comes from reaming renewable sources like solar, biomass, geothermal, wastes, and tidal wave ocean energy. Renewable generation technologies have been considered pollution free energy sources and their optimum use curtail the impact on environment, causes minimum secondary wastes, and have proved sustainable [2]. In present scenario, 657 GW of renewable power is contributed by the various renewable energy sources (RES) such as wind power, solar power, bio power, geothermal power, and concentrating solar thermal power and ocean power globally. Fig. 1 reveals that the total renewable power installed in top seven countries during from 2004 to 2014 [3].

All the RES except geothermal and tidal are the manifestation of ultimate energy of sun. The sun emits the 174,423,000,000,000 kWh amount of energy to the earth surface, also it can be expressed in terms of power i.e. about 1.74$\times$10¹⁷ W which is received by the earth's surface with a circular area of 1.27$\times$10¹⁴ m² and is about 1–2% of the energy received from the sun is transformed into wind energy and this meagre percentage is approximately 50–100 times higher than the energy obtained from the biomass, i.e. energy conversion from all the plants on this earth [4]. The wind is caused due to the natural flow of air across the sea or on the earth surface. The earth's rotation and temperature difference on account of uneven heating and cooling of its surface causes winds to blow. The heat received from the sun is absorbed by the land and water areas in varying amounts, as a result, warm air rises and cold air rushes to replace it and thus causing local winds. The wind power is operationally and commercially utmost viable RES for generation of power. Wind is considered the centerpiece of the efficient and economical energy. It is available abundantly in nature, is reasonably priced, and evenly distributed. Therefore, the wind resources on earth cannot be depleted, so long as civilization exists, whereas oil wells may go dry and coal seams will run out some day in future. This resource i.e. wind is now the mainstream electricity generation source, which plays a dominant role in long term energy plans for a number of countries [5]. Escalating fuel expenditures, growing energy consumption, and the stringent ecological regulations have led the power engineers to seek solution for alternate and sustainable sources of energy. Wind power is considered the largest developed and commercially available RES among the known hydro RES. Based on the recent developments including projected growth and generation cost of major renewable technologies, it has been concluded that the growth of the RES based power generation must be made mandatory globally to bridge the gap between demand and supply of electricity in future without effecting the environment [6].

The preliminary challenges concerning about sustainable development namely energy security, climate change, and energy access makes a persuasive case for wind energy utilization in large scale manner. Nevertheless, the regular winds are vary place to place and time to time in daily, annual, seasonal, diurnal patterns across the globe. However, it is important to access the wind power potential (WPP) at any given location or area to decide the capacity of wind resource for electricity generation within available time limit of wind duration. Therefore, it is pertinent to observe the wind characteristics and type of wind turbine (WT) technology suitable for any given promising location. These factors are very much helpful for wind power developers and investors to take a decision with respect to the economic constraints. Keeping in view all the wind parameters and characteristics, the aim of the present paper is to carry out a comprehensive literature review on wind resource assessment (WRA); which will be highly beneficial for the researchers, technocrats, and utility entities working in this domain, and to the developing countries where WPP has been partly harnessed. However, the research contributions by various researchers starting from very basic techniques to advanced techniques till date have been explored in the present work. The paper has been organized as given below: