& E6 s j2 k o8 S4 {# g/ aElectricity can be generated in many ways. In each case, ! q; {0 R9 j- y2 p- }. j9 D" T9 ea fuel is used to turn a turbine which drives a generator # i7 B0 ~* D( Z7 c% m0 ~9 N- twhich feeds the grid. The turbines are designed to suit the7 R. Z, m0 Q3 f( r
particular characteristics of the fuel. Wind generated electricity * G$ _4 J3 o5 d0 Q# Ais no different. The wind is the fuel – unlike fossil 6 \* I3 C0 \. I' Ofuels it is both free and clean, but otherwise it is just the ) K Y3 G( r! }+ F, h+ msame. It drives the turbine which generates electricity into ) ^ F' @; E4 _! N2 _. ]' J8 U% {a grid.9 e7 k: v; P. S' d- i" T
The politics and economics of wind energy have played an ^, o9 B$ |" V( r
important role in the development of the industry and contributed . i Y5 z* m0 S8 p/ z* X7 wto its present success. Engineering is, however, i. B! ~, R. D$ S) r
pivotal. As the wind industry has become better established,, a5 H; R t: q3 U* Y+ X6 F
the central place of engineering has become overshadowed , E8 S1 ]# O% B# gby other issues. This is a tribute to the success# x: F; D: g3 e/ P
of the engineers and their turbines. This volume addresses & P: ?. Z$ q& Sthe key engineering issues:4 j" y: N* r; }2 y, l& ]" v
• The turbines – their past achievements and future challenges # w x, M( {) X! i– a remarkable tale of technical endeavour and* O8 t$ `, f/ m4 |6 [. X
entrepreneurship. # r; L9 Q, N3 Q4 y• The wind – its characteristics and reliability – how can 0 P2 i9 J9 H9 q. @it be measured, quantified and harnessed? * R; l) X7 p/ C/ ?# S+ r• The wind farms – an assembly of individual turbines # B& k3 |. C, uinto wind power stations or wind farms – their optimisation4 g$ L; g0 u9 o9 f$ b0 ~
and development." Z/ B) b9 n' T* d/ Q
• The grid – transporting the energy from remote locations5 J5 {2 O: w# Z* L9 K
with plentiful wind energy to the loads – the key , @4 ~5 h) [+ J6 ]+ Ftechnical and strategic challenges. 1 t+ D/ k2 L* v, E% _This volume provides an historical overview of turbine* @, O: ?9 n- X0 M% R- E3 ]; d
development, describes the present status and considers + p8 i! O' p# i' _" q/ c1 `/ @+ B8 ufuture challenges. This is a remarkable story starting in 0 V N @: P: othe nineteenth century and then accelerating through the 2 A' Y% W% \( h! |- |last two decades of the twentieth century on a course very1 H/ N/ ~2 Y5 I* [; V' Y. P& R) Y
similar to the early days of aeronautics. The story is far1 Q4 f5 u" r/ f% U, {6 m& I2 p
from finished but it has certainly started with a 8 X% U. I5 B) _5 ]vengeance.' R6 H5 f9 h. T" [' E& L
Wind must be treated with great respect. The speed of the - D/ R! }; H' r9 W1 U% Fwind on a site has a very powerful effect on the economics, u+ D b4 g. d5 j
of a wind farm; it provides both the fuel to generate3 n3 S; A- v' G, F
electricity and the loads to destroy the turbine. This volume - l# u# [6 w1 w) udescribes how it can be quantified, harnessed and- D6 G7 c' `- G, n% g9 ^3 J' ?
put to work in an economic and predictable manner. The0 B8 L: V" a+ R M& p6 q9 i/ N
long-term behaviour of the wind is described as well as its" E' e$ ?6 y/ t+ B/ k
short-term behaviour. The latter can be successfully forecast' M( e9 V8 w% @ i: ?! e) U
to allow wind energy to participate in electricity markets. % D* U/ u' H0 |8 OIn order for wind to live up to its raw potential promise,0 D! p$ w+ B- V, P. n: D8 R
individual turbines must be assembled into wind farms or & W4 d9 x, f$ o& v' ]* Hwind power stations. The design and operation of the different ; B- @6 h# ?0 Ctypes of wind farms are discussed and examples+ W5 [9 M+ l. ^$ h& k |5 h4 k' s
provided. 7 h3 W" o* e# p: DFinally, the key strategic issue for the future is addressed: ) X: Y2 m: |" gHow can the windy parts of Europe, both onshore and offshore,+ n5 @# n T' p9 K/ N) k
deliver power for the industrial loads and population # T) S) F/ Y9 T1 Q8 Tcentres. This goal is achieved through the local, - H- A7 |' J, p- \" fnational and international grids. The way in which the grid1 q$ M8 F; _' a1 \% n
is used and constrained is a key political and technical4 a. n1 U8 Z# O
issue. The technical and regulatory constraints are . j v/ B) V) L( gdescribed and some challenges for the future are raised.' o! E6 L% K- ]7 C3 W- B2 q
This volume explores how this new, vibrant and rapidly 7 Y# m) w: u: K5 ~expanding industry exploits one of nature’s most copious D H5 ^/ N: g" w0 x. x1 _sources of energy – the wind.: o9 D l0 }! T+ X
+ @* s) S: ` c+ Y
) g: H) W8 D" r% ]9 p
INTRODUCTION TO VOLUME 1 3 ) L& D6 J2 [! e: ^5 @, mCHAPTER 1 TURBINE TECHNOLOGY 7 , ~. J+ ?: j; w' i" }. X7 C2 B1.1 Evolution of Commercial Wind Technology 7 # h% `: r/ ]* a' e3 q, ]5 z7 D1.1.1 Achievements 7 3 v3 ?# `1 n$ m% s ^; B; G+ \, x% o1.1.2 The Challenge 8' a5 N& ?8 J1 O& j
1.1.3 A Unique Technology 8 / j* `8 _6 {: D5 m. `6 f1 s: Y) v2 H1.1.4 Run up to Commercial Technology 9/ p& n. _4 |# |. b5 ^
1.1.5 Design Styles 10 ! s, {9 V" f6 k" K; x, `& @1.1.6 Design Drivers for Modern Technology 13 $ M& b; K" |2 }9 W( [+ s1.1.7 Growth of Wind Turbine Size 14 # @% {3 C) l( [$ s: }4 I1.1.8 Architecture of a Modern Wind Turbine 16 3 o& C) h0 q0 J/ u `5 I& Z1.1.9 Erection of Large Wind Turbines 17# B& d/ K; N. A, W. P
1.2 Technology Trends 19( X, D4 e& M* T) b* V1 }8 c
1.2.1 Larger Diameters 199 d* U3 x; ^, A3 f
1.2.2 Tip Speed - Offshore and Land Based Designs 20 6 \9 W. o0 k/ v( V: l1.2.3 Pitch versus Stall 21) d! T3 z1 A6 C2 h9 ?5 c
1.2.4 Speed Variation 21. H+ }% K2 |8 x7 z& Y
1.2.5 Hub Height 220 q* C& k; ?; A) y2 h2 D8 C. O8 J
1.2.6 Rotor Mass 22/ q1 `. Y# b# s6 j
1.3 Recent Developments 234 ^7 y, \8 I; w& i
1.3.1 Direct Drive Generators 23 / S5 f) s, N$ Y2 |1 i1.3.2 Hybrid – Single Stage of Gears and Multi-Pole Generator 25. _% q4 ~8 ~0 |5 o
1.3.3 Rotor Blade Developments 26 # V ?4 J4 J# I6 D0 u$ H7 Y1.3.4 Single Bearing Arrangement 282 P* N# x0 ?# C/ P
1.3.5 Offshore Technology 28 . l- G6 u( [' Z6 Q' D+ M( ?1.4 Technology Status 32 ( q# g+ U( P: c1 r& M8 {1.4.1 Overall Design Trends 32 ( t5 I O0 H6 u# @: G1.4.2 Size Limitations 33 , a7 I0 p3 B7 X1.4.3 The Success of Wind Technology 36 $ c1 L9 [" _2 Z1 C1 ], L1.5 Concluding Remarks and Future R&D 37! B. f p+ U2 A
CHAPTER 2 WIND RESOURCE ESTIMATION 38 $ j5 J$ \& x) \: s4 X2.1 Introduction 38; s9 x' M9 F: b
2.2 Regional Wind Resources 38 # }/ u. Y& C$ ^2.3 Wind Atlases 397 Q. Q3 m( o I1 m1 J2 z2 e
2.3.1 Onshore 392 ^( K) S& j# ^7 v/ m& l% Y
2.3.2 Offshore 41 / O5 ~: f* C! v+ B2.4 Energy Estimates 41 0 r. ^$ i {! A, a4 r# g+ n& [3 j2.4.1 Onshore 41 " E9 i* W. k0 N% d& u2.4.2 Offshore 44; m+ @2 y$ S9 S
2.4.3 Updating Resource Potential 44 ; Q3 ~: N6 G* _' f/ b2.4.4 Concluding Remarks 45 0 h; f/ r6 `" t9 ?2.5 Local Wind Resource Assessment and Energy Analysis 45( e! Q0 z! j9 t9 s
2.5.1 Introduction 45+ `6 M. N) W% B9 T, S
2.5.2 The Importance of the Wind Resource 47 2 f2 W u2 T- `$ V! F# X2 C% _9 q4 F2.5.3 Best Practice for Accurate Wind Speed Measurements 47" e' z4 w7 [! ]5 t: H) @
2.5.4 The Annual Variability of Wind Speed 49 - F0 N5 z W' i" N m0 s2 `2.5.5 Analytical Methods for the Prediction of the Long Term Wind Regime at a Site 534 ^& `! E, `/ Q) r5 ]0 E8 @/ S* \7 [
2.5.6 The Prediction of the Energy Production of a Wind Farm 554 n) j: t: l4 v Z
2.5.7 Definition of Uncertainty in Predicted Energy Production 57 " k3 L# |/ F+ a/ z2.6 Offshore Wind Farm Design and Resource Estimation 586 U6 [; C- _* l: F$ @8 n
2.6.1 Fundamentals 58 : O( @7 y/ \1 u+ j# j" @1 ]8 j4 D2.6.2 Measurement Offshore 59 $ n2 N+ ^9 C! r8 \3 Z2.6.3 Wind Analysis Offshore 59" s) E( C9 |: ]/ f% @0 ]" E4 `
2.6.4 Energy Prediction 59 / F/ e! q* q0 d2.6.5 Other Effects to Consider Offshore 59& j: r! ~% h. m* x5 P5 p
2.7 Forecasting 60 2 j0 ^( V, n6 E$ R2.7.1 Overview of the Method 61( N" a [" l5 Z: `* G
2.7.2 Improvement over Persistence 62 ! q Q& y4 K& u) X2.7.3 Power Output 62, p4 f+ T( E9 c. m7 c
2.7.4 Portfolio Effects 63 7 m2 v; I- [' Z' K% [. o2.7.5 Conclusions 63: J u/ B$ ^% X
2.8 Future Developments 63 ' C9 o, k5 l/ j! u @CHAPTER 3 WIND FARM DESIGN 659 P/ z! O }; o
3.1 Introduction 65) @( F- H4 O( q
3.2 Preliminary Layout Design 65 + c, ]+ Q+ n' t+ v- O/ D; c9 Q# \$ V3.3 Detailed Layout Design 65 8 c4 X, b% w4 @5 }: N; J; ~3.4 The Infrastructure 66 , e; R0 E6 ]9 g& S: @) x3.4.1. Civil Works 66 ( q+ `; i1 r" [" O# \! ^3.4.2. Electrical Works 67 [, k5 G3 N2 J# k! i" O/ {2 N1 ]
3.4.3. SCADA and Instruments 67 ( r1 n2 M7 _1 y6 w Y) f0 P3.5 Construction 67 x( ]! Z- A' k) W4 e3.6 Costs 685 Q( w1 p4 W7 l& L" ?* t+ [
3.7 Commissioning and Operation 68- o' i. F0 Y9 i* g5 d( s0 M2 z
3.8 Concluding Remarks 69" [# m0 r1 y0 ?% E- S3 Z% j5 r
CHAPTER 4 TRANSMISSION AND DISTRIBUTION NETWORKS 70$ y9 r o8 U3 E
4.1 Introduction 70 6 f* A) h# J# [+ C) @4.2 Setting the Scene 70& R, A1 c; v; F" u4 S
4.2.1 Large Interconnected Networks 70 / P4 c' z# B, u- C W4.2.2 Small Isolated Networks 71 % ~" V2 S6 U! ]8 H2 q4.3 Electricity Networks 72 ( j! Q. n( T/ \9 C* j8 R9 ?4.4 Considerations for Wind Energy 749 W. x$ A2 _4 w0 k1 }7 f
4.4.1 Connections 74 , {3 v: W. {: }% t! N8 P6 v& ]4.4.2 Operation 75/ \* d, p! i$ W; |- `; V
4.4.3 Strategic Planning Considerations 77 4 `% [! }7 u2 L9 w- {7 Q. W4.5 Issues for High Wind Penetration in Europe 80 - g7 p) [: y8 p. O4 l6 g4.6 Concluding Remarks 82' O4 V) k+ ~* I' L& j, ?( F0 b& E
CHAPTER 5 RESEARCH AND DEVELOPMENT 84+ _% \1 x7 L3 A7 ?3 S. C8 ~3 l: U
5.1 Wind Industry Research and Development Overview 84+ q3 B4 F9 H- J) h2 j/ z: x
5.2 Socio-Economic, Policy and Market Issues 85# T4 [2 z& S; L5 d
5.2.1 Transparency 85# V9 e* O& \1 j; e% W+ |! g
5.2.2 Increasing the Value of Wind Power 86 2 d9 @) W! h: ?0 S6 j5.2.3 Education and Human Resources Development 86 " P/ G8 z; H! D( k5.3 Environmental and Social Impacts 86 3 m7 u T7 t8 Y& F4 Q( Y' a5.4 Turbine and Component Design Issues 87" D0 _7 t ~' @, t/ H. A9 w
5.5 Testing, Standardisation, Certification and Safety 88. f' `, g; ]4 y# H# U
5.6 Grid Integration, Energy Systems, and Resource Prediction 88 * Y* }. \' {( y7 {% O, i4 i- J0 l5.7 Operation and Maintenance 89" |. B4 R+ A& R; R! O
5.8 Location of Wind Farms 90 - y9 `9 ^, N4 N+ q5.9 Offshore Wind 90' q4 m( Q9 i7 h" E/ I. O; @4 }
5.10 Multi-Megawatt Turbines 91 $ k) Z& I7 L( ~, R9 c7 P* ?4 s. b5.11 Summary of R&D Objectives 91