Lecture 6 Wind Power

Transcription

1 Lecture 6 Wind Power Basics of wind power Wind turbine Wind resources Wind power cost Wind power technology and trends Special issues: visual and sound effects

2 Global wind power scenarios 2050: 25% of all electricity could originate from wind power Grid parity around 2025

3 The Power of Wind How to calculate the energy contents of wind? Why is P~ v 3 Kinetic energy of wind (speed) U= ½ m v 2 =½ ρ A(δx) v 2 A(δx)= volume element of air A= area perpendicular to wind ρ= density of air Power density per unit area P= 1/A d(u)/dt= ½ ρ (δx/δt) v 2 = ½ ρ v 3

4 Basics of wind power (I) Power density of wind speed =½ ρ v 3, Air density from ideal gas law: ρ=p/rt = 3.48 P 0 /T exp(- g z/(rt)) P= pressure, T=temperature, z= height dt/dz= - 1 K/100m Density decreases with temperature and height Effect of surface friction on wind spped v(z)=v(z r ) ln(z/z 0 ) ln(z 0/ z r ), z 0 =surface roughness, r= reference point z 0 : ice 0,01 mm, Yield 10-30mm, forest 500 mm Also in the form v(z)/v(z r )=ln(z/z r )α,

5 Wind speed versus height Geostrophic wind speeds >200m Blades at different wind speeds Source:

6 Basics of wind power (II) Empirical observation on the distributional occurrence of wind speeds Wind speed distribution f(v)= b/v c (v/v c ) b- 1 exp(- v/v c ) b v c = scale factor, b= shape factor Weibull & Rayleigh distributions

7 Aerodynamics of wind power Lift perpendicular to wind (yaw moment), drag parallel to wind (rolling moment)

8 Betz Limit Maximum share of wind s kinetic energy that can be captured is 59.3% (Betz law); this is the maximum efyiciency of any wind turbine Power coefyicient C=P turbine /P wind ; typically x=v 2 /v 1 v 1 = wind speed upwind and v 2 = down-wind from turbine Source:

9 Components of a wind turbine Aero dynamical components (blades), power components (shaft, gear box, generator, power electronics), constructional components (nacelle, tower, foundation) Source: wikipedia, ECN

10 Different types of wind turbines Basic wind turbine types: horizontal and vertical turbines Vertical: Darrieus, Savonius, sprial types, normally small from 10 to 1000 W, < 100 kwsee Horizontal: 3- blade turbines, large >500 kw up to 5 10 MW, main wind turbine type Control of contact angle (blad); Yixed to controllable Speed of rotation: Yixed or variable Source: wikipedia

11 Power production of a wind turbine Power coefyicient C p =rotor /wind power = P rotor / (½ ρ v 3 ) C p =C p (λ), λ=ω R/v 0 = tip speed of rotor blade/wind speed C p, max =Betz limit= 59% Wind turbine power P=C p (ω,β,v) A ½ ρ v 3 A= rotor sweeping area Power curve P=P(v)=g(v)*v

12 Power curve of a modern wind turbine P=P(v)=g(v)*v, v= wind speed

13 Investment costs of wind turbines Present investment cost : on- shore > , offshore >1500 /kw; China USD/kW Future costs Learning curves (p=0.85) Trend curves Analysis by component Cost of a new design component- by- component assessment of costs Production cost of wind power (system LCOE)= investments + running costs interfacing cost + balancing power cost

14 Cost-breakdown of wind power

15 A typical cost profile of wind power

16 On-shore vs. off-shore wind power

17 On-shore wind power cost (US)

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19 Off-shore wind power costs (US)

20 Wind technology trends Larger unit size 2-3 MW à 5-10 MW On- shore à Off- shore Basic concepts: minimizing loads, maximizing performance Blades: new materials (aeroelastics), modularity Power transmission: gearless, permanent magnets, speed control, intelligent control Tower: mixed structures, load control Foundations: construction off- shore Interfacing grid: grid control (e.g. voltage) O&M: becomes important as volumes increase

21 Wind power technology 2030? New innovations à costs could drop by 40-50% Size could still grow 10MW= rotor Ø160 m, 20MW =220 m No physical limitations< 20 MW If weight could be controlled, 30-40MW units possible, transport may become a problem?

22 Examples on wind innovations

23 Future cost of wind power - size effects

24 Placement of wind turbines Placement Criteria for placement On- shore (FIN: 6-7 m/s) Off- shore (7-9 m/s) Inland (<4-6 m/s) mountains(7-10 m/s) Good wind conditions Infrastructure Land use Environmental

25 Future cost of wind power - capacity factor

26 Future cost of wind power stepwise improvements

27 Cost reduction potential (near-term)

28 Cost reduction potential

29 How to assess the cost of a new turbine design? Weight- based assessment model (scaling model) Component weight = F(rating) - - > Cost = H(weight) - - >Component cost = G (rating) Design parameters size weight model (load+weight) Cost of component = calibration coefyicient x cost/weight x complexity factor Calibration coefyicient= for each subsystem separately, statistical determination from existing plants Complexity factor = reylects the complexity of work in each components Total cost = Σ component costs

30 Example of weight model Rotor blade size vs weight and cost Costs don t necessarily increase linearly with size

31 Example of weight model tower

32 Exaple of applying the scaleing model

33 What s the minimum cost of wind power? Costs now in best conditions assume 1200 /kw, 3000 h/v, 1% O&M Cost of electricity = 0.08 (annuity factor) x 1200 / kw /3000 h x1200 /kw/3000 h = 36 / MWh Cost reductions during next 20 years? A) better wind conditions, B) better technology, C) mass production (economies of scale), D) integration to energy systems Example: onshoreà offshore wind power Investments off- s now 2000 /kw a. +20%, b. - 20%, c. - 20%, d %? Baseline cost 25 /MWh

34 Wind power in the electricity market Wind power is in left corner and push the whole curve to the right Lähde: H. Holttinen, VTT, luentokalvot

35 Wind Atlas Tuulen keskinopeuden (m/s) jakauma 100 metrin korkeudella 2,5 x 2,5 neliökilometrin tarkkuudella. Tarkempia karttoja osiossa Tuulen keskinopeuskartat sekä karttaliittymässä.

36 Wind speeds in Finland tuulen keskinopeuden (m/s) jakauma 100 metrin korkeudella 2,5 x 2,5 neliökilometrin tarkkuudella. Tarkempia karttoja osiossa Tuulen keskinopeuskartat sekä karttaliittymässä. Geostrophic wind speed

37 Temporal variation of wind speed in Finland

38 Wind power possibilities in Finland Wind production MWh/MW Off- shore GWh/km 2 By 2020: 6-8 TWh possible, by TWh OfYicial goal: 2000 MW by 2020 Source: VTT

39 Wind enegy in world scale (360,000 MW in 2014) Ref:WWEA

40 Wind capacity growth (Finland Nr32, 448 MW) Ref:WWEA

41 If you re interests to learn more about wind power Basics of wind power (self- reading, home exam, questions, web material, 2 points) Advanced Wind Power course: fall 2016 special course in wind energy (5 cr) Book: Wind energy explained - theory, design, applications, 580 s, self- reading + exam (8 cr postgraduate)

42 Your Work # 7 Home work from Lecture 6 How to avoid issues related to visual disturbance and noice from wind power plants? How to gain approval for large projects among local population? In preparing for Lecture 7 (Bioenergy) Have a look on the bioenergy stuff, just overview)