Katerine Dykes: 2013 Sandia National Laboratoies Wind Plant Reliability Workshop


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Katerine Dykes: 2013 Sandia National Laboratoies Wind Plant Reliability Workshop

  1. 1. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Wind Energy System Design & Engineering August 13, 2013 Katherine Dykes, Andrew Ning, Peter Graf, George Scott, Rick Damiani, Derek Berry, Ben Maples, Ryan King, Patrick Moriarty Maureen Hand and Paul Veers
  2. 2. 2 Outline • NREL NWTC Wind Energy Systems Engineering Program and Software o A Systems Approach to Wind Energy Research, Design and Development o Model and Tool Development o Initial Analysis Work
  3. 3. 3 Outline • NREL NWTC Wind Energy Systems Engineering Program and Software o A Systems Approach to Wind Energy Research, Design and Development o Model and Tool Development o Initial Analysis Work
  4. 4. 4 Motivation • Wind Energy Technology is a complex system o Many disciplines – aerodynamics, structures, electrical, etc o Many stakeholders – supply chain, developers, financiers, environmentalists, communities o Long time scales – operation over several decades o Large scope – activity within a single component to interaction of turbines within the plant to interaction of plant with the grid Environmental Impacts Grid Integration Impacts Wind Cost of Energy Community Impacts
  5. 5. 5 Wind Energy System Cost of Energy • Often use simplified Cost of Energy representation as global system objective: o Where COE is cost of energy, CAPEX is the sum of BOS is Balance of Station cost, TCC is Turbine Capital Cost (for full project), F is the financing rate to annualize investment costs, OPEX are the annual operating expenses and AEP is the net annual energy production
  6. 6. 6 Wind Energy System Cost of Energy
  7. 7. 7 • Current “NREL Cost and Scaling Model” uses parameterized functional relationships calibrated to historical trends o Originated with detailed design studies in early 2000s (WindPACT) o Abstraction to simple parametric relationships o Useful for two primary types of analyses on system costs: – Changing input factor prices over time – Scaling of conventional technology within a limited range o Publically available model Current structure of cost model Determining Wind Cost of Energy
  8. 8. 8 NREL Wind Energy System Engineering • The National Wind Technology Center (NWTC) wind energy systems engineering initiative has developed an analysis platform and research capability to capture important system interactions to achieve a better understanding of how to improve system-level performance and achieve system-level cost reductions. • NREL Initiative in Systems Engineering goal is to develop, maintain, and apply a software platform and to leverage its research capabilities to: o Integrate wind plant engineering performance and cost software modeling to enable full system analysis. o Apply of a variety of advanced analysis methods in multidisciplinary design analysis and optimization (MDAO) and related fields. o Develop a common platform and toolset to promote collaborative research and analysis among national laboratories, industry, and academia.
  9. 9. 9 Outline • NREL NWTC Systems Engineering Program Overview o A Systems Approach to Wind Energy Research, Design and Development o Software Development o Initial Analysis Work
  10. 10. 10 Systems Engineering Software Framework
  11. 11. 11 Systems Engineering Software Framework OpenMDAO: • Work flows integrate models together in structured ways (use of NASA’s OpenMDAO software) • Easily reconfigured (model selection and analysis structure) FUSED-Wind: • Support software for structured interface of wind turbine and plant modeling tools into OpenMDAO • Allows interchange of models, sharing of common turbine and plant input descriptions NREL WISDEM: • Collection of NREL engineering and cost turbine and plant analysis tools integrated into FUSED-Wind and OpenMDAO • Full wind turbine and plant model set planned for release
  12. 12. 12 NREL System Engineering Program Objectives • Integration of models into framework includes several areas: 1. Turbine component structure and cost models 2. Structural models with dynamic models of turbine performance 3. Integration of turbine models with physical plant models for turbine interactions affecting loads and energy production • At each level, a range of model fidelity is possible/needed for analysis flexibility (highly modular) NREL Cost and Scaling Model (Blade Cost) Example transition from Cost and Scaling Model to Systems Engineering Framework Blade Cost and Sizing Tool PreComp Sandia NuMAD pBEAM Blade MCM FAST AWS Truepower OpenWind
  13. 13. 13 Turbine Engineering Analysis Modules: Rotor Example AIRFOIL • Radial location, chord, twist • Profile shape • Lift curves and drag polars (Parameterized by Re and t/c) • Web locations ATMOSPHERE • Density • Viscosity • Shear exponent • Wind speed distribution LAMINATE STACK • Sequence of lamina • Number of plies • Ply thickness • Ply orientation • Ply material TURBINE INPUTS • Hub Height • Cut-in and cut-out speed • Min/max rotation speed • Rated power • Machine type (Fixed/Variable Speed/Pitch) • Drivetrain Efficiency ROTOR INPUTS • Number of blades • Precone, tilt ROTOR STRUCTURE & PERFORMANCE • Blade mass and moments of inertia • Cost • Power curve • Turbine AEP • Hub loads • Sound power level • Natural frequencies • Blade displacements • Panel buckling loads • Axial and shear stress <<< INPUTS OUTPUTS >>> • Geometry and Materials are pre-defined • Outputs include blade mass properties and rotor performance
  14. 14. 14 Plant Level Models: Turbine Capital Costs • Structure and cost models aggregate together for full turbine structure model preserving interactions between sub-systems •Rotor Speed •Max Thrust •Torque •Moment •Mass/Modal Properties •RNA Forces & Moments •RNA Mass/Modal Properties Turbine Model Component Costs and Properties: • Mass • Cost • natural frequencies • Deflection • critical buckling load • axial stress Turbine Capital Costs and Properties: • Mass • Cost TURBINE MODEL INPUT DESIGN PARAMETERS: • Wind, water and soil statistics • Rotor Diameter • Rotor Airfoil Class • Rotor Geometry • Drivetrain Gearbox / Generator Configuration • Machine Rating • Hub Height • Tower Geometry <<< INPUTS OUTPUTS >>> Drivetrain CST LSS • Length • Outer Diameter • Inner Diameter • Weight Bearing Positions Main bearings • Weight • Housing Weight Gearbox Configuration • Gear Number • Gear Type(s) • Overall Stage Ratio Gearbox • Weight • Stage Weights • Stage Ratios HSS & Coupling • Brake Weight • HSS Weight Generator Rating Generator • Weight Bedplate • Length • Area • Weight Yaw • Weight ROTOR Outputs • Diameter • Mass • Max Thrust • Speed at Rated • Torque at Rated <<< INPUTS OUTPUTS >>> Drivetrain Configuration Tower Outputs • Top Diameter Rotor CST Tower/Monopile CST RNA Assembly
  15. 15. 15 Plant Level Models: Finance / Cash Flow • Model takes inputs from all other plant models on costs and energy production • Model determines values of a variety of financial indicators of interest Cash Flow Finance Model CASH FLOW MODEL OUTPUTS: • Project NPV • Project IRR • Project COE / LCOE • Project PPB CASH FLOW MODEL INPUTS: • Electricity Price • Debt / equity ratio • Debt Interest Rate • Equity Rate • Tax Rate • Incentives • Project Timeline <<< INPUTS OUTPUTS >>> OTHER MODEL OUTPUTS: • Turbine Capital Costs • Balance of Station Costs • Annual Energy Production • Operations & Maintenance Costs
  16. 16. 16 Example analysis set-up: • Optimization of rotor and tower subsystem for overall cost of energy • Limited design variables and constraint set • Challenge is research design!
  17. 17. 17 Outline • NREL NWTC Systems Engineering Program Overview o A Systems Approach to Wind Energy Research, Design and Development o Model and Tool Development o Initial Analysis Work
  18. 18. 18 Initial Analysis Capabilities • Turbine component sizing tools allow for sub-optimization of various sub- components • Component outputs feed simplified component cost-models primarily based on NREL Cost and Scaling model data • New NREL Balance of Station Cost model and ECN O&M Offshore Cost model used for plant costs • Energy production determined by AWS Truepower OpenWind Community or Enterprise versions • Simpler NREL Cost and Scaling model able to substitute for any of the cost model modules
  19. 19. 19 Initial Analysis: Sensitivity Study • Parameter scans on basic turbine design parameters: o rotor diameter o hub height o rated power o maximum allowable tip speed
  20. 20. 20 Initial Analysis: Sensitivity Study • Any analysis requires both turbine and plant design inputs: o Study uses NREL 5-MW reference turbine model and offshore reference site. NREL 5 MW Reference Turbine Parameter Value Rotor: Rotor Diameter 126 m Rated Wind Speed 12.1 m / s Cut-In / Cut-Out Wind Speeds 3 m /s / 25 m / s Maximum Allowable Tip Speed 80 m/s Tower: Hub Height 90 m Tower Length / Monopile Length 60 m / 30 m Tower Top / Base Diameters 3.87 m / 6.0 m Tower Drivetrain Configuration 3-stage Geared (EEP) Rated Power 5 MW Gearbox Ratio 97:1 Drivetrain Efficiency at Rated Power 94.4% Offshore Site Conditions Distance to Shore 46 m Sea Depths <5% at ~20 m, 25%+ at ~30 m Wind Speed at 90 m Mean = 9.78 m/s Weibull shape = 2.15, scale = 10.5 Significant Wave Height 10-year Extreme = 7.5 m 50-year extreme = 8 to 8.5 m/s Significant Wave Period 10-year Extreme = 19.6 s
  21. 21. 21 • Baseline COE analysis CSM versus CSTs – Overall cost of energy higher using new model set: • Energy production of higher fidelity physics-based model slightly higher. • Turbine capital costs are similar between two models – slightly higher for the NREL CSM due to the inclusion of a 10% “marine-ization” factor • O&M costs roughly consistent from old to new model on first analysis • Balance of Station costs of NREL CSM were known to be very low – new model (still in develop) estimates BOS costs as much higher – COE for new model closer to industry-reported offshore wind costs for European projects. Initial Analysis: Sensitivity Study NREL CSM NREL SE w/ CSTs COE $0.11 $0.18 AEP (MWh / turbine-yr) 18,800 19,900 Turbine Capital Costs ($ / kW) $1,200 $1,000 BOS Costs ($ / kW) $1,700 $3,600 O&M Costs ($ / kWh) $0.027 $0.026
  22. 22. 22 • Sensitivity of system cost to changes in key parameters (rotor diameter, rated power, hub height, and maximum tip speed) performed – change of +/- 10% for each. • Example analysis: rotor diameter. – Changes in COE was more pronounced using new set of models that capture more system coupling: • Rotor diameter influences balance of station model in latter case; overall BOS impact on costs of energy higher for new model set. • Impacts on energy production are much higher due to power curve changes • Turbine capital cost are lower since costs are now associated with component masses rather than directly to rotor diameter Initial Analysis: Sensitivity Study Percent Changes in Parameters NREL CSM NREL SE w/ CSTs Rotor Diameter (m) -10.0% +10.0% -10.0% +10.0% COE ↑ ↓ ↑ ↓ AEP (kWh / turbine-yr) ↓ ↑ ↓↓ ↑↑ TCCs ($ / kW) ↓↓ ↑↑ ↓ ↑ BOS Costs ($ / kW) -- -- ↓ ↑ O&M Costs ($ / kWh) ↓ ↑ ↓ ↑
  23. 23. 23 • Multidisciplinary Design Optimization Study # 1: – Joint aerodynamic and structural optimization of a wind turbine rotor using new NREL rotor aero and structural analysis tools – Dual objectives for maximization AEP and minimization of weight – Select design variables (i.e. chord and twist) and add appropriate constraints (i.e. stress limits) Initial Analysis: Multidisciplinary Optimization
  24. 24. 24 • Multidisciplinary Design Optimization Study # 2: – Optimization of a full integrated design of wind turbine and plant under uncertain site wind climate conditions – Overall objective to minimize overall cost of energy for the wind plant (under uncertainty of wind conditions) – Choose design variables (i.e. rotor diameter), add constraints and sources of uncertainty (i.e. site weibull distribution parameters) Initial Analysis: Multidisciplinary Optimization
  25. 25. 25 1. A systems perspective to wind energy cost and performance analysis is essential – extensive coupling exists between physical assets over long periods of time. 2. NREL has developed initial capability for modeling integrated wind plant systems for performance and cost. 3. Initial work shows improved representation of coupling in analysis results; however, model improvement is needed across all system models. 4. Research design becomes critical with a flexible tool Conclusions and Summary
  26. 26. 26 Discussion / Q&A http://www.nrel.gov/wind/systems_engineering