Wind Energy Engineering

A Handbook for Onshore and Offshore Wind Turbines

Trevor M. Letcher, Trevor Letcher

• Publisher: Academic Press
• Year: 2017
• eBook ISBN: 9780128094297
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Wind Energy Engineering: A Handbook for Onshore and Offshore Wind Turbines is the most advanced, up-to-date and research-focused text on all aspects of wind energy engineering. Wind energy is pivotal in global electricity generation and for achieving future essential energy demands and targets. In this fast moving field this must-have edition starts with an in-depth look at the present state of wind integration and distribution worldwide, and continues with a high-level assessment of the advances in turbine technology and how the investment, planning, and economic infrastructure can support those innovations. Each chapter includes a research overview with a detailed analysis and new case studies looking at how recent research developments can be applied. Written by some of the most forward-thinking professionals in the field and giving a complete examination of one of the most promising and efficient sources of renewable energy, this book is an invaluable reference into this cross-disciplinary field for engineers. - Contains analysis of the latest high-level research and explores real world application potential in relation to the developments - Uses system international (SI) units and imperial units throughout to appeal to global engineers - Offers new case studies from a world expert in the field - Covers the latest research developments in this fast moving, vital subject

Part I

Introduction

Outline

Chapter 1 Why Wind Energy?

Chapter 1

Why Wind Energy?

Trevor M. Letcher, University of KwaZulu-Natal, Durban, South Africa Email: [email protected]

Abstract

The raison d’etre for the new book on wind energy engineering is discussed with a focus on our changing climate and the buildup of atmospheric carbon dioxide; hence the title of this introductory chapter—Why Wind Energy? The background to wind power is briefly mentioned.

The advantages of wind energy are discussed together with a look at the challenges facing the wind energy industry. The chapter ends with a brief look at the potential of wind energy as one of the most important of the renewable forms of energy.

Keywords

Wind energy; climate change; wind turbine technology; advantages of wind energy; challenges facing the wind turbine industry

1.1 Introduction

Wind Energy Engineering: A Handbook for Onshore and Offshore Wind Turbines is aimed at giving an overview and an insight into most aspects of wind energy. The industry is rapidly reaching a mature stage and it was felt that the time had come to take stock of the wide-ranging topics linked to the generation of electricity from wind. These topics include: an historical background; the reasons for the interest in wind energy; the fundamental science behind the industry; engineering aspects of building wind turbines, generating electricity, and coupling to the grid, environmental issues; economics; and the future prospects of the industry. Having all these disparate topics in one volume of 26 chapters gives the reader a chance to get know the subject and for the specialist to delve deeper. The latter will be rewarded with copious references to the latest work for further study. This book is an outcome of an earlier book we published, entitled Future Energy: Improved, Sustainable and Clean Options for Our Planet, 2nd edition (Elsevier, 2014), where only one out of thirty one chapters was devoted to wind energy.

1.2 Climate Change

Today with the specter of global warming and climate change looming over us, there is a need for the energy industry to find energy sources free of carbon dioxide pollution. Energy-related carbon dioxide (CO₂) emissions contribute the majority of global greenhouse gas (GHG) emissions (66%) [1]; these include: electricity production, transport in all its forms, cement making and industry, to mention a few. The fight against climate change must become an important feature in energy policy-making, but the implications are daunting. The emission goals pledged by countries under the United Nations Framework Convention on Climate Change (UNFCCC) are laudable but it is still not enough to reach the level of keeping global warming to just 2°C above the preindustrial level by 2035. This temperature rise was first mooted in 1996 by the environment ministers of the European Council who declared that “global average temperatures should not exceed 2 degrees above the pre-industrial level.” It took until 2010, when the Cancun Agreement was signed, before the 2°C was enshrined in an international climate policy agreement to “hold the increase in global average temperature below 2°C above preindustrial levels.”

The spotlight is on the renewable energy industry to find energy sources free of carbon dioxide pollution. The other options are to reduce our consumption of energy and consequently our standard of living or to capture CO₂ and bury it in caverns or under the sea (capture and storage, CCS). For many reasons, including our natural reticence toward lowering our standard of living, the cost of CCS, the increasing rise in the population of the world, the aspirations of all to a life with available electricity, it is unlikely that these two options will prevail. To put the problem in perspective, the world energy production (this includes: transport, electricity, heating, and industrial) reached 570 EJ (13, 800 million tonnes of oil equivalent (Mtoe)) in 2014, up 1.5% from 2013 [2,3]. In spite of dire warnings there seems to be little international governmental control in reducing this. Fossil fuels still account for 81% of this production—0.4% lower than in 2013—in spite of rising oil (+2.1%), coal (+0.8%) and natural gas production (+0.6%). A small positive sign on the horizon was the fact that during 2014, the energy production by renewable forms of energy did grow significantly, albeit from a low base. For example, hydroelectricity production was up 2.5% and accounted for 2.4% of global energy production, while wind and solar photovoltaics continued their rapid growth (+11% and +35%, respectively), but accounted for around only 1% of global energy production. In 2014 nonfossil sources, biofuels, and waste accounted for 10.2% of world energy production. Nuclear energy contributed 4.7% to the global energy production [3].

In this book we will focus our attention on electricity generation from wind energy. In Future Energy [1] we reported that the production of electricity worldwide was responsible for 26% of the global GHGs (mainly CO₂ and CH₄). Fossil fuel was responsible for producing 65% of global electricity (coal 38%, gas 22%, and oil 5%) (see Table 1.1) [4]. Wind and solar energy are at the forefront of the drive to significantly reduce the GHGs to meet the 2°C limit. This is largely because we know that if we can replace fossil fuel with wind and solar energy for generated electricity, we can significantly reduce CO₂ emissions. At the moment wind turbines (433 GW in 2015) [5] have a greater installed capacity, worldwide, than do solar photovoltaics (242 GW in 2016) [6], but this is still a mere drop in the ocean. Wind and solar energy produce only 4% of the global supply of electricity [4]. There is much work to be done. Unfortunately, coal, the worst of the fossil fuel polluters, is still the main energy source for generating electricity. The chief culprits are China, the United States, and Australia; coal produces 72% of China’s electricity (total electricity is 5145 TW h) and 38% of the USA’s electricity (total electricity is 4255 TW h). Australia is the largest exporter of coal (metallurgical and thermal) in the world (35%) and in 2010–11 exported 283 Mt of coal with more than half going to Japan and China. It was forecast that this figure would increase by over 70% to 486 Mt in 2016–17 [7]. This does fly in the face of the Australian Federal Government’s renewable energy target of producing 33 TW h of electricity from renewable sources by 2020 [8,9].

Table 1.1

Total World Electricity Production in 2014 [4]

Energy Source	World/%	Euro 27/%	North America/%	Asia/%
Coal	38	26	33	59
Natural gas	22	15	28	13
Hydroelectric	17	11	13	15
Nuclear	11	27	17	4
Oil	5	2	2	4
Biomass, solar, tides	4	9	2	3
Wind	4	9	4	2
Total energy/TW h	22, 433	3062	5211	9372
Average power/GW	2559	350	594	1069

With well-developed wind and other renewable energy industries, we will not need to consider fracking, exploiting tar sands for oil and gas, or any other environmentally unfriendly fossil fuel mining; we should be working toward a situation where our huge fossil fuel reserves in all its forms are left in the ground. In reality, this will only come about when wind energy and other renewable forms of energy become cheaper and more convenient to use than fossil fuel. With mass production and bigger and more efficient wind turbines, this might well come about in the next decade.

1.3 Background

The extraction of kinetic energy from wind and its conversion to useful types of energy is a process which has been used for centuries. It is believed that the first windmills were invented 2000 years ago by the Persians and also by the Chinese and were used to grind corn and also to lift water (see Chapter 8: Wind Turbine Technologies). Later the Dutch would develop windmills to drain their land in the 14th century and, by the 19th century, millions of small windmills were installed in the United States and throughout the world for pumping water (from boreholes) and for stock and farm home water needs. The 19th century also saw the development of small wind machines (0.2–3 kW producing 32 V direct current) in rural areas in America to operate appliances. These early developments came to an end when the 1936 Rural Electrification Administration was created and grid electricity was supplied to most rural communities. The generation of grid electricity, using wind turbines, has its origins in the United States in the 1970s. Its development was initiated by the need to replace energy derived from fossil fuels with renewable forms of energy. Of all the renewable forms of energy (wind, solar, geothermal, and hydroelectric), wind and solar have shown very positive growth. Over the past 11 years wind energy capacity has increased from 48 to 433 GW; solar PV from 2.6 to 242 GW; hydro from 715 to 1000 GW; and geothermal from 8.9 to 12 GW [10,11]. These figures reflect the maximum possible power available and not what was actually delivered. For example, the electricity obtained from hydroplants in 2014 was 3769 TW h which, when averaged over ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Preface
• Part I: Introduction
• Part II: Wind Resource and Wind Energy Worldwide
• Part III: Wind Turbine Technology
• Part IV: Generation of Electricity
• Part V: Environmental Impacts of Wind Energy
• Part VI: Financial Modeling/Wind Economics
• Part VII: Investment, Growth Trends, and the Future of Wind Energy
• Index