GCEP Energy Tutorial Wind 101 Patrick Riley October 14, 2014 Imagination at work. Agenda • Introduction & fundamentals • Wind resource • Aerodynamics & performance • Design loads & controls • Scaling • Farm Considerations • Technology Differentiators • Economics • Technology Development Areas GCEP Wind 101| 14 October 2014 2 © 2014 General Electric Company – All rights reserved Power from Wind Turbines Power in Wind 1 3 Pwind = 2 r v Area v = wind speed Extractable Power from Wind turbine Importance of site identification (local wind resource) & understanding of wind shear 1 3 Pwind = 2 cp r v Area Area = rotor swept area Power increases with rotor2 Cp = power coefficient a measure of aerodynamic efficiency of extracting energy from the wind GCEP Wind 101| 14 October 2014 3 © 2014 General Electric Company – All rights reserved Configurations Horizontal-Axis (HAWT) Vertical-Axis (VAWT) Upwind vs. Downwind Lift Based (Darrieus) vs. Drag-Based (Savonius) Source: http://en.wikipedia.org/wiki/File:Darrieus-windmill.jpg Source: http://en.wikipedia.org/wiki/File:Savonius-rotor_en.svg Copyright 2007 aarchiba, used with permission. Copyright 2008 Ugo14, used with permission. Source: http://en.wikipedia.org/wiki/File:Wind.turbine.yaw.system.configurations.svg Copyright 2009 Hanuman Wind, used with permission. Number of Blades Airborne Wind Turbine Source: http://en.wikipedia.org/wiki/File:Water_Pumping_ Source: http://en.wikipedia.org/wiki/File:Airborne_wind_generator-en.svg Windmill.jpg Copyright 2008 James Provost, used with permission. Copyright 2008 Ben Franske, used with permission. GCEP Wind 101| 14 October 2014 4 © 2014 General Electric Company – All rights reserved Utility-Scale Turbine Types Convergence of industry Horizontal axis Upwind 3 blades Variable rotor speed Active (independent) pitch Main differentiators Direct drive vs. gearbox Generator design Full vs. Partial Power Conversion Controls GCEP Wind 101| 14 October 2014 5 © 2014 General Electric Company – All rights reserved Basic Wind Turbine Terminology Term Typical Value* Definition Rated Power 1.6MW Max nominal power output Diameter 100m Rotor diameter Capacity Factor 48% Annual Energy Production (kWh) Rated Power (kW) x 24 x 365 Avg wind speed 7.5m/s Annual average wind speed at hub height Turbulence Intensity 16% sU/Uavg @ Uavg = 15 m/s IEC class II Uavg = 8.5 m/s @ hub height 50-yr, 10-min extreme wind = 42.5 m/s 50-yr, 3-sec extreme gust = 59.5 m/s Turbulence = 18% (IEC = International Electrotechnical Commission) Design life 20 years Calculated Life according IEC 61400 and DP’s *values can vary significantly with turbine & site GCEP Wind 101| 14 October 2014 6 © 2014 General Electric Company – All rights reserved Utility Scale Wind Uniqueness Massive Structural Size Substantial Heights 2.5-120, 110m HH GE 1.6-100 Rotor (170m) 40 to 70 tons Statue of Hoover Liberty 77 to 120m diameter Tower (91m) (87m) Nacelle 57 to 82 tons Tower Source: Source: 132 to 1200 tons http://en.wikipedia.org http://en.wikipedia.org/wiki/ /wiki/File:Hoover_Towe File:Statue_of_Liberty_7.jpg r_Stanford_January_2 Placed in the Public Domain 60m to 139m hub height 013.jpg Copyright 2013 King of Hearts, used with permission. … but Values Low Cost Design … Simplicity GCEP Wind 101| 14 October 2014 7 © 2014 General Electric Company – All rights reserved Conventional Layout High-speed coupling Pitch drive Main bearing Pitch bearing Gearbox Mechanical brake Hub Bed Frame Yaw drives Generator Yaw bearing Electrical ‘top box’ Rotor main shaft GCEP Wind 101| 14 October 2014 8 © 2014 General Electric Company – All rights reserved Wind Resource Average Wind Speed Map The Wind Resource is the #1 Driver of Wind Economics The most productive wind sites: • have high average wind speeds • are generally somewhat Source: http://www.nrel.gov/gis/images/80m_wind/USwind300dpe4-11.jpg Copyright 2011 AWS Truepower & NREL, used with permission. remote from population Installed Wind Power Map centers GW installed 0 • integration with utility grid is 0.5 1 1.5 generally challenging 2 2.5 3 3.5 4 4.5 >5 GCEP Wind 101| 14 October 2014 9 © 2014 General Electric Company – All rights reserved Wind Characteristics Wind Speed Distribution Wind direction distribution WindWind-Shear shear Profile 12% Vwind 10% 8% 6% % 4% 2% WindSpeed Distribution, 0% 0 10 20 30 Ground Wind Speed, m/s Source: http://commons.wikimedia.org/wiki/File:Wind_rose_plot.jpg Copyright 2010 BREEZE Software, used with permission. Extreme winds 1-yr & 50-yr extreme gusts Turbulence intensity TI=s/ s : std. dev. : average IEC Class A: 18% at 15 m/s IEC Class B: 16% at 15 m/s Copyright TOM, used with permission. GCEP Wind 101| 14 October 2014 10 © 2014 General Electric Company – All rights reserved Voice of Physics – Actuator Disk Theory Actuator disc Model • Rotor is a permeable disc • Velocity reduction is equally distributed before/after the rotor and V2 = (1 2a)V1 a: Axial Induction factor for slow down • Power: Change in momentum caused Source: http://commons.wikimedia.org/wiki/File:Betz_tube.jpg Placed in the Public Domain by Anthony vh by pressure difference across disk 1 3 2 P = m pd = 2 rV1 Ad 4a1 a for V2=0: only load, no power Wind speed (static) Pressure Main Results Stream tube Power 2 Power coefficient: = 3 = 4a1 a Actuator disc c p 1 1 2 rV1 Ad d 2 Thrust 1 = = 4a1 a Cp Thrust coefficient: ct 1 2 0.8 2 rV1 Ad 0.6 Ct Betz Limit Maximum extractable Power is 59.3% 0.4 Coefficients 0.2 Power& Thrust 0 GCEP Wind 101| 14 October 2014 0 0.1 0.2 0.3 0.4 0.511 Axial Induction Factor, a © 2014 General Electric Company – All rights reserved Optimizing Cp’s through Configuration Horizontal-axis wind turbines • More blades increase Cp … but increase cost Vertical-axis lift (Darrieus) • Limited applicability due to lower Cp Horizontal -axis windmills • Designed for torque not electricity … results in low tip speed operation Vertical-axis drag (Savonius) • Used as primary technology for anemometers Source: http://www.intechopen.com/books/fundamental-and-advanced-topics-in-wind-power/wind-turbines-theory-the-betz-equation- and-optimal-rotor-tip-speed-ratio Copyright 2011 Magdi Ragheb and Adam M. Ragheb , used with permission. GCEP Wind 101| 14 October 2014 12 © 2014 General Electric Company – All rights reserved Power Curve 5 12% Wind Distribution 4.5 Turbine loads & costs correlate closely to power in wind 2.5-120 10% 4 Power in Wind (Betz Limit) Significant added cost to continue extracting power in 3.5 b wind 8% 3 MW , a Not enough wind to make effort 2.5 6% to capture energy worthwhile Distribution 2 Power 4% 1.5 Dominated by aero, mechanical, Wind & electrical losses 1 2% 0.5 0 0% 0 5 10 15 20 25 30 Wind Speed, m/s a) Power is for a 120m rotor diameter turbine b) Wind distribution calculated from Weibull distribution, 7.5 m/s average wind speed, k=2 GCEP Wind 101| 14 October 2014 13 © 2014 General Electric Company – All rights reserved Annual Energy Production (AEP) t(bin)[h] c [] p(bin) Power [kW] Energy Yield (bin)[kWh] 500 700,000 0.50 2500 450 0.45 600,000 400 0.40 2000 350 500,000 0.35 electric 300 aerodynamic 0.30 "power curve" 1500 400,000 250 0.25 300,000 200 0.20 1000 = 150 0.15 200,000 100 0.10 500 100,000 50 0.05 0 0.00 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 0 2 4 6 8 10 12 14 16 18 20 22 24 0 2 4 6 8 10 12 14 16 18 20 22 24 v [m s] (bin) v(bin)[m s] 3 1 2 t(bin) v(bin) r cp elec.(bin) R = AEPactual Weibull 2 AEP is the product of: •Wind distribution – v3 •Rotor size (swept area) – R2 •Efficiency (aerodynamic, mechanical, electrical) GCEP Wind 101| 14 October 2014 14 © 2014 General Electric Company – All rights reserved Power Curve – Regions • Power curve region: Cut-in Rated Cut-out 1 below cut-in Wind speed Wind speed Wind speed 2 cut-in to rated 2,500.0 30 (partial power) 1 2 Peak3 Shaver 3 rated to cut-out 25 2,000.0 • Variable speed: Power control: pitch to feather 20 RPM ~ wind speed 1,500.0 • Constant speed: 15 RPM RPM constant PowerPower [kW] [kW] Power [kW] 1,000.0 pitch, thrust, RPMRPMthrust,thrust, pitch, pitch, Fine pitch 10 • Pitch actuation: > Fine pitch 500.0 5 > Peak shaver variable constant speed speed > Power control 0.0 0 (Thrust) Load reduction 0 5 10 15 20 25 Wind Speed [m/s] PowerPower Thrust [20*kN] RPM [-]RPM [-] pitch [deg] GCEP Wind 101| 14 October 2014 15 © 2014 General Electric Company – All rights reserved Loads Analysis Simulation Driven ... incorporate wind turbulence, control strategy, aero & structural properties Structural Design ... used to design components Certification ... meet specific design load cases (DLC‘s) • IEC 61400 ed. 2 / ed.3 (-1 onshore; -2 small; -3 offshore) • DIBt (partly identical with IEC, but HH-dep.- windspeeds, add. DLCs) WIND TURBINE CLASS IEC 61400-1 Ed2 I II III • NVN 11400 (similar to IEC) Vave [m/s] 10 8.5 7.5 Bankability … required by customer & Vref [m/s] 50 42.5 37.5 financing institutions TI15 [%] a / b 18/16 18/16 18/16 Air density [kg/m³] 1.225 Vertical shear [-] 0.2/ 0.11 GCEP Wind 101| 14 October 2014 Flow angles [°] < 8 16 © 2014 General Electric Company – All rights reserved Site Specific Mechanical Loads Analysis Determine turbine loads suitability at site specific locations GCEP Wind 101| 14 October 2014 17 © 2014 General Electric Company – All rights reserved Square-Cube Law Energy capture is proportional to RD2 Loads Mass Cost are proportional to RD3 Energy Loads … Mass … Cost EnergyCost& Rotor Diameter … but this is a generalization & some economies of scale exist Installation Tower BOP Power Electronics … and some step changes like blade logistics GCEP Wind 101| 14 October 2014 18 © 2014 General Electric Company – All rights reserved Turbine scale … costs and benefits BOP cost + Turbine cost = Total CapEx Technology Technology $/MW BOP $/MW BOP CapEx Turbine $/MW Turbine Nameplate Nameplate Nameplate Technology advancements required to beat the cost curve GCEP Wind 101| 14 October 2014 19 © 2014 General Electric Company – All rights reserved Wind System Engineering Objectives Goal: Assess the system-level value of new technologies & next-generation product Current Technology designs New Technology • Many system-level trades rating & rotor diameter hub height LCOE Change control strategies (loads vs.