Boulder,March 11st 2010

Proposal for a site assessment IEC standard

IEC/TC88 Boulder meetingMillán Esteban - SC88 Spanish mirror committee

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 2

The expression “site assessment” is the common designation for assessment of site specific conditions.

The objective is the consecution of a set of environmental and others site conditions which are relevant for assessing the suitability of the design and structural integrity of a wind turbine at a specific site.

What does it mean “site assessment” ?

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 3

Need of a site assessment standard

IEC61400-22 “IEC System for conformity testing and certification of wind turbines” states that site conditions must be assessed in order to obtain the project certification.However it lacks the basis for carrying out such assessment

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 4

Aim of a site assessment standard

Provide a traceable basis for establishing the site specific conditions that demonstrate conformity with the design parameters or to be used in load calculations for comparison with design loads.Common understanding of the site assessment procedures stated in IEC61400-1 between : manufacturers, promoters, certification bodies, banks, assurance companies.Provide an accurate estimation of the uncertainty of the obtained site specific parameters that can be compared with that asumed in the calibration of IEC61400-1.

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 5

Conditions to be evaluated

Wind conditions:Annual average 10 min. wind speed distributionExtreme wind speed with a recurrence interval of 1 and 50 yearsTurbulence intensity (characteristic and extreme)Wind shear (mean, negative, extreme)Upflow

Topographic complexity of the site.Wake effects from neighbouring turbinesOther environmental conditions (density, temperature,humidity, icing,solar radiation,...).Electrical conditions.Soil conditions.Earthquake conditions.

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 6

Conditions to be evaluated (2)

Marine conditions:WavesSea currentsTidal movementsSea iceMarine growthSeabed movement, etc…

Convenience of separate IEC61400-XX-2 for offshore marine conditions ????

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 7

What does not include?

The site assessment standard does not include:

wind resource assessment of a wind farm installed at the siteEnvironmental impact studies due to installation of a wind farm at the site

21ts of February of 2010 Copyright 2008 Gamesa Corporación Tecnológica, S.A. 8

Technical specification vs. international standard

In our opinion the new site assessment project should initially be published as technical specification.

After gaining general acceptance it could be further updated to international standard status

Boulder,March 11st 2010

THANK YOU