1. Wind Power Analysis Using Non-Standard Statistical Models
Niall McCoy
School of Electrical Systems Engineering
Prof Jonathan Blackledge
15th February 2013

2. Introduction Name: Niall McCoy. Qualifications:
Degree in Electrical Engineering 2008 (DIT);
Degree in Energy Management 2010 (DIT);
Chartered & Professional Engineer 2012 (EI).
Company & Position:
Electrical Engineer of Wind Prospect Group, based in Carrickmines, Co Dublin.
Roles & responsibilities:
International Project Management & Electrical Design.
Academic Works:
Commenced Part-Time PhD with DIT October 2011;
Published one academic paper to date in December 2012 in association with Prof Jonathan Blackledge;
“Analysis of Wind Velocity and the Quantification of Wind Turbulence in Rural and Urban Environments using the Levy Index and Fractal Dimension ”

3. Agenda Project Background Research Methodologies
Current Industry Standards
The Urban vs Rural Resource
Next Steps

4. Project Background Project Background Research Methodologies
Current Industry Standards
The Urban vs Rural Resource
Next Steps

5. Why is Wind Energy Analysis Important?
Currently circa 2,158MW of installed wind generation on the system.
Current energy demand of 35,532GWh¹.
Target of 40% system demand to be via renewable energy by 2020, 35% of which to be wind.
Resulting in a requirement of circa 39,852GWh (SD in 2020)² where 35% must be sourced from wind generation.
Applying capacity factors of 0.31, the required installed capacity for wind generation by 2020 is 5,178MW¹.
¹ EirGrid 2013
² Wind Prospect 2013
Le Tene Maps 2013

6. Why is Wind Energy Analysis Important?
Main reason – Wind Farm Development & Financial Risk;
Wind farm developments require capital investment to be developed;
Financial return is directly linked to the wind speeds at the site;
Financial risk is amplified in the energy prediction due to the relationship between turbine output and wind speed;
To avoid financial disadvantages, uncertainties must be minimised in:
Wind resource assessment
Power curve performance (Turbine output at specific wind speed)
Turbine availability

7. What has Financial Risk to do with Wind Energy Analysis?
To have confidence in an investment, you need confidence in the wind resource and associated studies;
Wind studies are performed to understand that return on your investment;
All current wind studies carry a degree of uncertainty and potential for error. All stages of the wind study aim to minimise uncertainty, resulting in a “best guess”;
Therefore the Aim of the Project
Design a more accurate model of wind energy analysis with reduced errors;
Provide a reduced risk profile to investors;
Increase funding access to wind projects and increase wind energy penetration on the Irish system.

8. Research Methodologies
Project Background
Research Methodologies
Current Industry Standards
The Urban vs Rural Resource
Next Steps

9. Non-Standard Statistical Models
In order to find a more accurate forecasting model for wind energy at a potential wind farm location are number of equations have been looked at;
Non-Gaussian model for simulating wind velocity data;
Levy distribution for the statistical characteristics of wind velocity;
Thus, deriving a stochastic fractional diffusion equation for the wind velocity as a function of time whose solution is characterised by the Levy index;
Eventually deriving both to establish Levy index using Betz law to understand the energy output of a specific turbine.
Betz’s Law – Windpower.de 1999
Illustration of Betz’s Law – Windpower.de 1999

10. Current Industry Standards
Project Background
Research Methodologies
Current Industry Standards
The Urban vs Rural Resource
Next Steps

11. Current Measurement Systems
Met Tower Measurement System
WTG Measurement System
NRG System 2010
Vestas 2013

12. Power Law vs Log Law Profiles
Power law profile:
α = wind shear coefficient
Log law profile
Requires knowledge of u* and z0
Both must be estimated

13. Data Sources & Sets Fully calibrated industry standard anemometers;
10 minute average data set from 80m metrological mast, with cup anemometers located at heights of, 50m, 65m, 80m & 82.5m;

14. The Urban vs Rural Resource
Project Background
Research Methodologies
Current Industry Standards
The Urban vs Rural Resource
Next Steps

15. The Urban vs Rural Resource
𝑢 𝑧 = 𝑢∗ 𝑘 𝐼𝑛 𝑧−𝑑 𝑧0
– u(z) denotes the wind speed at height z
– u*friction velocity
– κ the Von Karman constant
– z height above the earth’s surface
– d displacement height
– z0 height above the earth’s surface roughness
Mertens 2006

16. The Urban vs Rural Resource
Main Aim of the paper;
To quantify rural and urban areas in terms of the Levy index using data generated from industry standard sources;
The emphasise is based on a theoretical basis, where;
gamma= 1 for 'perfect' urban area (i.e. full diffusion)
and = 2 for 'perfect' rural area (i.e. perfect laminar flow).
In practice, 'perfect' never exists but the differences in gamma for the two environments appears to reflect the hypothesis.
Greenspec 2011

17. Non-Gaussian results of the Urban & Rural Wind Resource
Project
SOLU
WDIT
ICLT
KING
DKIT
Urban Location
Newport
Waterford
Limerick
Cavan
Dundalk
Co-Ordinates X
503732
659727
553282
679051
704775 Y
571087
610694
564665
766272
806261
Qmean
1.4918
1.4628
1.4640
1.4590
1.4110
RABR
KNLR
DUNM
CRIG
DROM
Rural Location
Mayo
Wexford
Louth
Tyrone
511370
706819
695381
628938
549251
794745
657023
785030
868785
645517
1.4607
1.4721
1.5235
1.4836
1.4929
Five rural and five urban sites were analysed through determination of the Levy index over a period of 12 months.
The Table show that, bar one anomaly, the trend is that the mean values of the Levy index for the rural sites is consistently higher in comparison to the mean values of the same index for the urban sites.
Resulting in the urban-to-rural ratio of
Levy index using data generated from industry standard sources

18. Urban vs Rural the Conclusion
In conclusion, it can be stated that the wind resource in the urban environment is curtailed due to the influencing factors such a surface roughness, turbulence intensity, etc...
When a direct comparison is drawn between the urban and rural wind resources at selected location across Ireland and the UK, using similar reference heights, fully calibrated equipment and stochastic models to define the results. It is evident that the rural resource is generally of a higher energy yield when compared to the urban resource.
For the full paper see -

19. Next Steps Project Background Research Methodologies
Current Industry Standards
The Urban vs Rural Resource
Next Steps

20. Conceptual Non-Gaussian CFD Model
Next Steps
Detailed look at developing a non-Gaussian based energy yield platform model and possibly CFD software;
Challenge current industry energy analysis model accuracy, such as Wind Pro & WaSP, with newly development model/software;
Introduce more complex influences, such as specific types of surface roughness, turbulence intensity, etc..;
Wind Pro & WaSP model
Conceptual Non-Gaussian CFD Model

21. Q&A
Any Questions?