challenges for lean/efficient manufacturing of wind turbines in

ReGen Powertech Pvt.Ltd1

Challenges for Lean/Efficient Manufacturing of Wind Turbines

in India to bring down cost

15th - 17th February 2011International Conference on Wind Energy, New Delhi

Wind Energy : 20 by 2020


Challenges for Lean/Efficient Manufacturing of Wind Turbines

in India to bring down Cost

WTG Cost Elements


Reference Turbine : 1.5MW (Geared), three-bladed, Pitch - Controlled, 70 m rotor ,

advanced Power Converter

Control & Safety System andVariable Speed Electronics

8.5%

WTG Cost Elements


Rotor22.5%

Generator & Nacelle

25%Tower16.5%

BOS 27%

Reference Turbine : 1.5MW (Gearless), three-bladed, Pitch - Controlled, 77 m rotor ,

advanced Power Converter

Control & Safety System and Variable Speed Electronics

9%

• Rotor Blades Hub

Pitch Mechanism & Bearings

• Drive Train, Nacelle, Generator Low Speed ShaftBearingsGear BoxMechanical Brake, HS couplings etc.,GeneratorYaw Drive and BearingMain FrameElectrical ConnectionsHydraulic System

Nacelle Covers


WTG Components

• Control & Safety System and Variable Speed Electronics

• Tower

• BOS (Balance Of Station)

Foundation

Transportation

Roads, Civil works

Assembly and Installation

Electrical Interface/Connections

Permits, Engineering


WTG Components

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Production Strategies by current leading manufacturers

The Strategy employed ranges from vertically-integrated companies (such as Enercon), through to companies including

GE, Repower and Nordex that source almost all components from third parties.

ReGen Powertech Pvt.Ltd

• Technology Improvements

• Value Engineering/Re-engineering

• Indigenization / Localisation

• Supply Chain Management

• Lean Production

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Cost Reduction for Mfg. WTG - Approaches


• Inventory Management

• Quality

• Logistics

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Cost Reduction for Mfg. WTG - Approaches


• Advanced (Enlarged) Rotors

• Manufacturing

• Advanced Tower Concepts

• Drive Train Improvements

• Advanced Power Electronics

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Cost Reduction -Technology Improvements


• Blade costs can be reduced with structural/aerodynamic designimprovements that would reduce blade costs upto 10%, below arelevant base line. An integrated design process that optimizes theblade design from the point of structural load carrying capacity andmanufacturing ease with aerodynamic design should be adopted.

• There would be substantial increase in capital costs in case oflonger and heavier blades that would increase gravity loads on theentire WTG system.

The solution lies in development of lighter weight blades by usingadvanced materials like carbon-fiber, 3D weave and new matrixmaterials such as toughened resins and advanced manufacturingprocesses.

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Technology Improvements - Advanced (Enlarged) Rotors


• NREL estimates a reduction upto 10% in blade costs just goingto carbon-hybrid materials.

Reduced rotor mass results in reductions in the rest of thesupport structure especially in the tower in the order of 2%.With blades accounting for 10% to 15% of turbine costs, thenet result is 2 to 6%

• Advanced Control strategies that might offer the ability toreduce loads by 20% to allow 10% rotor growth and 10%annual energy capture improvement should be adopted.

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Technology Improvements- Advanced (Enlarged) Rotors


• Blades:

Advanced & Automated Manufacturing Processes:

The automation of manufacturing will be wide spread formanufacture of large blades like introduction of Resin infusiontechnology dispensing with hand lay-up process. It reduces labourcosts and improves part quality. This resin infusion technologyeliminates excess resin resulting in reduced material use.

• Towers:

Onsite forming techniques for tower sections may reduce fabrication and transportation costs.

• Lower Margins:

The partial safety factors designated in certification codes such as IEC and GL are high because of the uncertainty in loads, materials and fabrication processes. Manufacturing Processes that are more consistent and reliable, when backed up by testing, will allow for reduced safety factors.

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Technology Improvements - Manufacturing


• Gear Boxes:

Advanced gear profiles:

This technology represents a fundamental change to geartooth geometry that may enable gear boxes to be made withless material for the same load-carrying capability. Thereforeat a lower capital cost.

• Integrated Gear/Generator system:

Cost reductions may be realized by integrating major drivetrain components such as the gear box, generator and the bedplate. This forces adjacent structural components to carryadditional loads and perform more than one function whicheliminates or significantly reduces the size and weight ofsupporting structure.

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Technology Improvements - Drive Train Improvements


• Single Stage/Permanent Magnet Generators (PMGs)

These generators are larger in diameter and have many generator polepairs that allow them to produce 50 Hertz power without spinning at thehigh speeds necessary for standard generators. These medium-speedgenerator spin at 150rpm compared to 1200 to 1800 rpm for normalinduction generators. These generator designs are coupled with a single -stage gear box that is much more compact and less complex ( fewer gearsand bearings) than multi-stage gear boxes used in most wind turbines. Thepermanent magnets in these generators, instead of copper woundrotors, further reduce their weight and size.

• Multi-Generator

Multiple drive paths-extracting power from multiple drives from a singlebull gear. This approach effectively reduces the torque that each drivepath must be designed for, reducing size and load carrying capacity of thegearing. This machine drive train and nacelle are significantly smaller andlighter than would be expected from other main stream designs usingmultiple stage speed increasers and a single generator.

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Technology Improvements - Drive Train Improvements (contd)


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Technology Improvements - Drive Train Improvements (contd)

• Direct Drive

This drive train design approach eliminates gear box altogether. Agenerator with many poles is used to develop a low-speed generator. Inthis design, the generator turns at the speed of the rotor and varyingfrequency output is conditioned in power electronics. This design can beimplemented using either wound pole generator or PMG.

• Generator Cooling:

More efficient method of heat rejection in windings will reduce weight ofthe generator

• Higher Energy Product Magnets :

The flux density of magnets has been increasing steadily as manufacturingprocesses improve. High flux density magnets could change the internalrotor design and perhaps allow more compact design that are morerobust.


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Technology Improvements - Advanced Power Electronics

• Power Electronics (PE) will become an increasinglyimportant part of modern Wind Turbines.

The use of PE include Frequency Converters toprocess all turbine power; control devices like lowvoltage ride through, reactive power control, voltagecontrol etc., to satisfy new grid codes for a greaterrange of grid compatibility.

Insulated gate bipolar transistors revolutionizedthe medium power market. Other new devices, suchas symmetrical gate commutating thyristors andmetal-oxide semi-conductor controlled thyristors,may make inroads into the market.


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Percent decrease in COE from baseline from Technology Improvements

14%

2%

4%

5%

3%


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Cost Reduction - Value Engineering/Re-engineering

• Site specific/Wind Turbine Class specific TowerDesigns

• Re-engineering of WTG Foundations for differentvariants based on Soil Bearing Capacities and usingIndian Standards for Foundation design.

• Packaging of WEC Unit Sub-station


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Cost Reduction - Indigenisation

• Indigenisation of Components and Sub-assemblies greatly help Cost Reduction efforts.

• There should be a Mechanism in the Industry , together discuss and identify and develop potential Indigenous Vendors

• Industry together make Investment for phased Manufacturing Program

• Industry together , may be through Association, negotiate

prices with the Components Sub-delivery Vendors who are now starting their manufacturing units in India viz. Bearings, Yaw drives & Pitch Drives , Brakes etc.

• Governmental Support is needed by the Industry for R&D activities in Indigenisation and Technology Improvement efforts


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Cost Reduction - Further Indigenisation/Localisation

• Frequency Converter Panels (In-house)

• Pitch Systems (In-house)

• IGBTs (Semikron India)

• Tower Flanges (SE Forge, Bharat Forge)

• Yaw Drives & Pitch Drives (Bongfiglioli)

• Brake Calipers (Svendborg-by 2011)

• Special cables (Nicco)

• Cylindrical roller bearing-Main Bearing (SKF- by 2010)

• Hydraulic Power Packs


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Cost Reduction - Supply Chain Management• Supply Chain Simplification can greatly simplify Supply

Chain Management

• Development of Strong Vendor Base with minimum of 3

reliable Vendors

• Vendor Partnerships can save more money than low-bidding

• Sound Negotiations for Prices & Terms

• Tracking of Market Trend and Forecasting of Metal Prices

(Steel & Copper) and procuring at right time

• Supply of Steel and Copper as ‘free-issue’ material to

Fabricators / Sub-Vendors


Concerted effort by Industry required to develop more vendors in India for the following items

• Heavy SG Iron Castings (Base Frames, Hubs, Shafts) with machining

• High Tensile Heavy Fabricated components with machining

• Tubular Steel Tower (especially in Western India)

• Tower/Tower Head Fasteners

• Yaw Drives and Pitch Drives

• Generator Stampings Steel and Copper coil


Cost Reduction – Supply Chain Management

• Lean manufacturing is a philosophy that considers the expenditure of resources for any goal other than creation of value for the end customer is wasteful and thus target for elimination

• It aims to reduce waste in many forms - Material, time, Idle equipment and Inventory are example.

• It aims for doubling Labour Productivity, cutting production throughput times and cutting errors

• Tools available

– 5 S (Sort, Set in Order, Shine, Standardise and Sustain)

– Six Sigma (achieving failure rate of 3.4 parts per million opportunities or perfection of 99.9997 % perfection)


Cost Reduction – Lean and efficient Manufacturing

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Cost Reduction - Quality

• Quality Costs can be greatly reduced

• Quality Product Reduces Re-Works/ Re-

Placement Parts thereby curtailing wasteful

expenditure and increasing profits

• Quality Costs in manufacturing can be

eliminated with six-sigma programme


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• Sourcing tubular towers and blades nearer to project sites

• Building Partnerships with Reliable Transporters

• Material Pre-Planning.

• Load Optimization.

• Utilizing Inter - Carting vehicles on multi-locations (or)

Direct delivery to site location.

Cost Reduction - Logistics


• Reduction on halting at Loading & Unloading Points.

• Purchase or lease of fleets to reduce transportation cost on

movements.

• Development of proper roads by Authorities between local/

State Highways and Wind farm sites


Cost Reduction - Logistics

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Summary• Cost Reduction for manufacturing WTG can be achieved through

Strong in-house R&D set up for undertaking Technology Improvements and

serious Value Engineering efforts of the existing designs

Focussed and collective Indigenisation efforts

Efficient & Effective Supply Chain Management, Inventory Management and

Lean Production Methods

Diligent Logistics Organisation, Planning & Methods

• WTG Cost Reduction efforts will bring down Turbine capital costs and

result in narrowing down the difference in Cost Of Energy (COE) between

Wind Power and Conventional Power

• Recommendation : Cost Reduction groups should be set up inWind Turbine Manufacturing companies and a ‘Core Group’ ofthe Companies may be formed and discuss freely the ideas andapproaches towards Cost Reduction of WTG.


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A Cleaner Tomorrow Begins… Thank You


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