Due Diligence on Wind Energy
Projects
Site Assessment
30. October 2012, Ho Chi Minh City, Vietnam
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Outline
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1) Introduction – Lahmeyer International GmbH
2) Site Assessment
3) Bankability criteria
4) On-site wind measurement
5) Wind farm planning and layout
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Distances
Turbulences
Turbine and site suitability
Environmental restriction
• 6) Wind studies
• 7) Norms and guidelines
• 8) Appendix
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Lahmeyer International GmbH
Overview
Company
Lahmeyer International GmbH (LI)
Founding Year
1966
Headquarter
Bad Vilbel, Germany
Services
Technical and economic planning and
consulting services
Fields of Activity - Energy
- Hydropower and Water Resources
- Transportation
LI Group
6 Associated Companies
Employees 2011
LI Group:
1500
Turnover 2011
LI Group:
150 million Euro
Representatives
in 50 Countries
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Lahmeyer International GmbH
Divisions & Departments
Energy Division
Hydropower and Water
Resources Division
Transportation
GE 1 – Electrical Engineering
GE 2 – Transmission and Distribution
Interdisciplinary
technical advisor….
GE 3 – Privately Financed Projects
… covering the
whole energy
industry.
GE 4 – Thermal Power Plants
GE 5 – Renewable Energies I
GE 6 – Renewable Energies II – Wind Energy
GE 7 – Economics and Energy Efficiency
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GE6 – Wind Energy Department
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Global Presence
LI has provided wind energy services in over
65 different countries around the world.
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GE 6 – Wind Energy Division
Key References
• Wind measurements masts installed
> 240
• Country wide wind mappings
> 14
countries
• Wind potential evaluations
> 300
wind farms
• CFD wind studies
> 120
wind farms
• Feasibility studies
> 80
wind farms
(> 3,300 MW)
• Due diligence studies
> 600
wind farms
(>12,500 MW)
• Construction supervision
> 60
wind farms
(> 1,700 MW)
• Operation and maintenance supervision
> 90
wind farms
(> 2,800 MW)
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GE 6 – Wind Energy Division
Example: Zafarana IV Wind Park, Egypt
Client
New and Renewable Energy Agency (NREA)
Main Data
• Installed capacity:
80 MW
• Number of wind turbines:
94
• Type of turbine: Gamesa:
G52, 850 kW
• Annual Energy Generation: 244 GWh p.a.
Execution
Services
• Implementation Plan
2005-2010
• Tender procedure (incl. O&M Contract)
• PPA and tariff elaboration
• Construction Supervision
• O&M Supervision
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GE 6 – Wind Energy Division
Example: Gangwon Wind Farm, Korea
Client
Unison Corporation, Korea
Main Data
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Installed capacity:
Number of wind turbines:
Type of turbine: Vestas
Annual Energy Generation:
Execution
98 MW
49
V80 – 2.0MW
244 GWh p.a.
2004-2011
Services
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Project Management
Complete Planning and Engineering
Full-time Construction Supervision
Site Management
Commissioning
Quality Control and Assurance
O&M Supervision
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GE 6 – Wind Energy Division
Example: Development of 3 Wind Farms in Sudan
Client
MINISTRY of ELECTRICITY AND DAMS (MED), SUDAN
Main Data
• Planned capacity:
• Foreseen turbine type:
30 MW
800 – 2,500 kW
Execution
2011-2014
Services
• Update of Feasibility Studies:
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Assessment of the available wind data
Wind farm siting
Energy yield calculation
Supervision of wind measurement
campaign
Electrical and civil wind farm layout
Review of electrical conditions
Economical and financial analysis
Steering of CDM registration process
• Design and Tendering
• Preparation of Conceptual Design
• Preparation of Tender Documents
• Coordination of Tender process and contract
negotiations
• Construction supervision
• Supervision of Construction
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GE 6 – Wind Energy Division
Example: Feasibility Study Wind Energy on Phu
Quoc Island, Vietnam
Client
Electricity of Vietnam Power Company No.2
Main Data
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2 existing Diesel power stations: 7 MW (total installed capacity) O/HFO fired
generation (end 2005): 5 MW
Existing distribution network: OH; 22kV (MV); 0.4kV (LV)
Forecasted total demand by the end of 2010: 50 MW
Execution
Services
• Phase I: Feasibility Study
• Wind Resource Assessment
(Identification of the five most
promising locations)
• Site selection
• Wind farm concept
• Basic calculation of Specific
Electricity Generation
2005-2006
• Phase II: Conceptual Design
• Power demand analysis
• Electrical grid qualitative
analysis
• Optimization of the wind farm
layout
• EIA and resettlement plan
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Site Assessment
Task of Site Assessment:
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Measurement and analysis of wind conditions
 Benefit: Early knowledge may save your money in case of too low wind conditions
 Benefit: Knowledge about the risks, e.g. turbulences, extreme wind conditions
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Annual energy production
 Benefit: Allows you to calculated the profitability of your wind project (in case FIT is available) or to
calculate the PPA
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Wind farm layout and micro-siting
 Benefit: Licensable layout, considering restrictions, e.g. environmental, setbacks towards roads, high
voltage lines, railways, residents
 Benefit: Choice of most suitable turbine
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Environmental impact assessment
 Benefit: Helps you to improve your layout in case results exceeds local laws
• Country wide or area specific wind mapping
 Benefit: Know the hot spots
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Site Assessment
Goals of Site Assessment:
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Knowledge about the wind conditions of your site
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Site suitability
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Wind speed
Wind direction
Turbulences
Extreme wind condition
Air density
Choice of right turbine type
Layout respecting restrictions
Bankable and reliable wind and energy study
Calculation of the income side and profitability
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Site Assessment
Bankability criteria
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On-site wind measurements
Modelling with proper models, like WAsP for simple terrain and CFD for complex
Wind farm layout
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Distances
Restrictions
Turbulence
Available land
Turbine suitability
Site suitability
Bankable wind resource and energy studies by independent consultants
Bankable is what a bank accepts, even if they deviate from
norms, guidelines and common practice
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On-site wind measurement
Why on-site measurement, instead
of only modeling?
• All models, regardless if static (WAsP) or dynamic (microscale CFD, meso scale
atmospheric models) have inherent limitations. Especially extrapolation of wind
speed to greater heights above ground is problematic and affected with high
uncertainty.
• Turbulence data and vertical profile at a complex site can only precisely be
determined by measurement
• Extreme wind speed calculation for turbine class assignment is more reliable with
on site measured time series
• Indispensable precondition for project financing
• Additional data for temperature, humidity, pressure and solar radiation can be
gathered
• Reduction of uncertainty because of „real“ wind data
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 lowers risk for banks and investors
 increasing of your project value
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On-site wind measurement
Key requirements to wind
measurements
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Representative mast position
In complex terrain more than one mast
Measurement height minimum 2/3 of planned hub height
State-of-Art sensors
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„First Class“ anemometers
Individually calibrated anemometers
Measurement of wind speed, wind direction, temperature
Optionally air pressure, humidity, flow inclination
Wind speed sensors (anemometer) at minimum three different levels; minimum
distance 20 m
Wind direction at two heights
Mounting and mast design according to IEC 61400-12 Annex G
Measurement documentation according to Measnet
Minimum measurement period 1 year
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Permanent monitoring during measurement to avoid major failures
On-site wind measurement
Quality of energy results stands or
falls with the wind measurement
 More technical details in Annex
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Wind Farm Planning and Layout
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Defining site borders (land availability, etc.)
Site access (nearby roads, complexity of the site, etc.)
Exclusions areas (e.g. distance to suburban areas, houses, streets, etc.)
Wind Resource
Distances between the turbines
Respecting restrictions (e.g. noise, shadow flicker, animals)
Obstacles (Rivers, mountains, villages, roads, transmission lines and other
obstacles)
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Wind Farm Planing and Layout
Distances
Restrictions
Turbulences
Available land
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Distances
Rule of thumbs:
• 3-5 rotor diameter distance 90° to the
main wind direction
• 5-10 rotor diameters distance in main
wind direction
• The larger the wind farm, the more
distance should be kept
• Orientation: Minimum 90 % park
efficiency (=10 % wake losses)
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Turbulence
Source: http://f2e.de/de/services/beispiele/nachlaufstroemung-wea-2
Wake turbulence
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Turbine suitability
Choosing the right turbine for the site
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IEC Classification
Hub height, rotor diameter
Transport possibilities
Availability (supply)
Service possibilities
Restriction
Track record
Proven technology
Reputation of manufacturer
Site suitability
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Assessment of IEC class and subclass
Turbulence calculation
Site suitability confirmation of manufacturer
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Site Suitability Analysis
• Qualified on-site wind measurement required
• Assessment of IEC Classes:
• Reference wind speed (Max 10min wind speed in 50yrs)
• Average annual wind speed
• Turbulence Intensity
Wind class
I
II
III
Vref
50 m/s
42.5 m/s
37.5 m/s
Vave
10 m/s
8.5 m/s
7.5 m/s
Turbulence class at 15 m/s
A
18.0 %
18.0 %
18.0 %
B
15.7 %
15.7 %
15.7 %
C
13.5 %
13.5 %
13.5 %
• Calculation of turbulence intensity including:
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Ambient and representative turbulence intensity
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Effective turbulence intensity
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Site Suitability Analysis
• IEC III are made to low wind region
• Huge rotor diameter compared to small rated capacity
Examples:
Manufacturer Turbine
type
Rotordiameter
[m]
Hub height
[m]
Rated
Power [kW]
Vestas
V112
112
84, 94, 119,
140
3000
Vestas
V126
126
119
3000
Nordex
N117
117
91, 120, 141
2400
Gamesa
G114
114
93, 120, 140
2000
Goldwind
GW109
109
90
2500
Goldwind
GW106
106
80, 90
2500
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Site Suitability Analysis
Power curve comparison IEC I and IEC III
3000
2500
Power [kW]
2000
1500
N90 2,5 MW IEC I
N117 2,4 MW IEC III
1000
500
0
Wind speed [m/s]
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Environmental restrictions
Shadow
Distance to housing areas
Noise
Distance to housing areas
Wild Live
Endangered Species – Bird trails
Landscape
Distance to National Parks, Monuments, etc.
Country specific requirements
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Wind park planning
Wind park planning, available land and exclusion areas merged
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Wind park planning
Wind resource map
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Wind park planning
Wind park planning, micro siting at optimal positions
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Bankable wind study
Key requirements to a bankable
wind study
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Site visit
Quality control of wind data
Measure-Correlate-Predict (MCP)-Procedures (gap filling)
Long-term correlation with suitable long-term references
Vertical / Horizontal Flow Modelling Procedure
Gross energy yield
Loss estimation
Uncertainty estimation
Probability of Exceedance (PoE)
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Relevant norms and guidelines
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IEC 61400-12 Annex G
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IEC 61400-1 Ed.3: Wind turbines – Part 1: Design Requirements
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Specifies essential design requirements to ensure the engineering integrity of wind turbines
Measnet: Evaluation of site specific wind conditions
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Mounting of instruments on meteorological mast
Site inspection
Relevant meteorological parameters
Representativeness of wind measurements
Measurement documentation
Data evaluation and extrapolation
Derived results
Reporting
Technical Guidelines for wind turbines Part 6: Determination of Wind Potential and
Energy Yields
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German guideline published by non-profit organization: Foerdergesellschaft Windenergie e.V. (FGW)
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Q&A
Thank you for your kind
attention
Contact:
Anil Bindal
Tel: +49 (0) 6101-55-1676
Email : anil.bindal@lahmeyer.de
Website:
www.lahmeyer.de
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Q&A
Appendix
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On-site Wind measurement
Sensors
• State of the art: „ First Class“ cup
anemometers, with high measurement
accuracy and relatively high insensitivity
regarding turbulence and low power
consumption
• Wind speed sensors individually
calibrated in wind tunnel
• Wind direction measured with wind vanes
• Redundant wind speed (on same height
above ground) and direction sensors
(different heights)
• Additional sensors for temperature,
humidity, pressure and evtl. solar
radiation
well-designed
poor-designed
Source: IEA Expert group study: 11. Wind speed
measurement and use of cup anemometry
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On-site Wind measurement
General recommendations for met mast siting
Representative position within wind farm
Covering of as much turbine positions as possible within
representative radius
Position free from obstacles within a radius of 20-30 times obstacle
height
Position with regular flow conditions
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Not on or behind sharp ridges (recirculation zones)
Not in depressions
Preferably in flat area or on smooth shaped hills
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On-site Wind measurement
Placing of met mast(s) on the Wind farm site
Questions to be answered:
How many met masts are necessary?
Which height of mast is necessary?
Where to put the met mast(s)?
Additional measurement of vertical profile necessary?
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On-site Wind measurement
Number of met mast(s) on the wind farm site
Two terrain types can be distinguished!
Simple terrain (Desert)
- Minor Relief
- Negligible influence of orography on wind speed
- Wind conditions only influenced by roughness
Complex terrain (Italian Alps)
- Significant relief
- Slopes with steepness > 30%
- Wind conditions influenced by roughness and
orography
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On-site Wind measurement
Representative radius of met masts
Terrain type
Minimum
measurement height
a. g.
Representative radius of
mast (max. distance of any
wind turbine to mast)
Simple Terrain: (Example
Desert)
2/3 of hub height
10 km
Complex Terrain:
(Example Italian Alps)
2/3 of hub height
(mast on
plateau), hub
2 km
height if mast on Could be even less in very
ridge
complex terrain
Source: MEASNET-Evaluation of site specific wind conditions, 2009
- Significant relief
- Slopes with steepness > 30%
- Wind conditions influenced by roughness and
orography
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On-site Wind measurement
Flow disturbances of tubular and lattice tower
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On-site Wind measurement
Example of State-of-the-Art Design: Top Sensors
Source: IEC standard 61400-12-1
Alternative according to IEC 61400-12: no single top sensor, two sensors at same
height mounted on booms.
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Site Assessment
Example for State-of-the-art design: Lower sensors
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