Modeling and Control of Wind Turbine

Chapter 1

Abstract

meteorological uncertainty.

humidity

3

1. Introduction

Energy Systems

Weifei Hu, Zhenyu Liu and Jianrong Tan

Thermodynamic Analysis of Wind

This chapter studies the efficiency performance of wind energy systems evaluated by energy and exergy analyses. The theories of energy and exergy analyses along with efficiency calculation for horizontal-axis wind turbines (WTs) are provided by a lucid explanation. A 1.5 MW WT is selected for the thermodynamic analysis using reanalyzed meteorological data retrieved from the National Aeronautics and Space Administration's (NASA) Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2), data set. Matlab scripts are developed to calculate the energy and exergy efficiencies using the MERRA-2 data set. The energy efficiency presents higher magnitude than the exergy efficiency based on the theoretical derivation and the calculated time series of efficiencies. Comparison of impacts of four meteorological variables (wind speed, pressure, temperature, and humidity ratio) on WT efficiencies shows that although wind speed dominates the turbine's efficiency performance, other meteorological variables also play important roles. In addition, uncertainties of the meteorological variables are represented by the best-fit distributions, which are critically important for evaluating the reliability of wind power performance considering realistic

Keywords: wind energy, thermodynamic analysis, energy efficiency,

exergy efficiency, meteorological uncertainty, wind speed, pressure, temperature,

Global installed wind power capacity has been tremendously increased over the

last 15 years from 23,900 MW in 2001 to 486,790 MW in 2016 [1]. More than 314,000 WTs are now operating around the world, which accounts for more than 4.3% of 2015 global electricity demand. Yet it is still far from ambitious targets, e.g., increasing wind energy's contribution to 20% of US electricity supply by 2030 [2]. To approach that, it is of critical importance to accurately evaluate the WT perfor-

The most common factors that are considered when planning a wind farm include substantial wind resources, landowner and community support, feasible permitting, compatible land use, nearby access to electrical grid, appropriate site conditions for access during construction and operations, aviation compatibility, and favorable electricity market [3]. However, the influences of meteorological variables (e.g., pressure, temperature, and humidity) are often neglected which

mance considering realistic environmental conditions.
