Wind speed tolerances

Summary

The requester asked for specific wind speed tolerance data (cut-in, cut-out, survival speeds) for proposed turbines at Earystane & Scard, but the Manx Utilities Authority responded that the information is not held because no final decision on the turbine make or model has been made.

Key Facts

• The Manx Utilities Authority does not hold the requested wind speed data as there is no standard measure applicable without a specific turbine model.
• No final decision has been made regarding the size, make, or model of the turbines for the Earystane & Scard sites.
• Wind turbines at the site will not operate during very low or very high wind speeds to protect assets and avoid degradation.
• The Environmental Impact Assessment process includes gathering accurate wind speed data to ensure turbine design withstands extreme conditions.
• The authority directed the requester to a Tynwald House of Keys recording from 30 April 2024 for further context on turbine types.

Data Disclosed

• 2024-05-07
• 2024-05-24
• 3843609
• 30 April 2024
• 1hr 35:48
• 1hr 40:15
• IM99 1PS
• 01624 687687

Exemptions Cited

• Information not held

Original Request

Please provide details of the rated wind speed 'cut in', 'cut out' and 'recut in' for the turbines proposed at Earystane & Scard. Please provide details of the rated speed at the point in which the turbine generator will be disengaged and break applied. Please provide the survival speed that the turbine can withstand without sustaining damage or failure. Please confirm if the MUA specification includes a high wind speed option that tapers the cut-out speed and what AEP increase percentage this would provide?

Data Tables (1)

Full Response Text

Manx Utilities PO Box 177, Douglas Isle of Man, IM99 1PS

e: enquiries@manxutilities.im t: 01624 687687 www.manxutilities.im

Our ref: 3843609 24 May 2024

Dear ###

We write further to your request received 7 May 2024, which states:

"Please provide details of the rated wind speed 'cut in', 'cut out' and 'recut in' for the turbines proposed at Earystane & Scard.
Please provide details of the rated speed at the point in which the turbine generator will be disengaged and break applied.
Please provide the survival speed that the turbine can withstand without sustaining damage or failure.
Please confirm if the MUA specification includes a high wind speed option that tapers the cut-out speed and what AEP increase percentage this would provide?"

While our aim is to provide information whenever possible, in this instance the public authority does not hold or cannot, after taking reasonable steps to do so, find the information that you have requested. This is because there is no standard measures for these minimum/maximums or values, as they can vary and are dependent on the specific wind turbine manufacturer, make, model and specification. There has been no final decision made on the size, make or model.

However, to provide some assistance, a recent Tynwald question regarding wind turbines did explain the latest position regarding the type of turbines being considered for the site. Find this here: https://www.tynwald.org.im/business/listen, and the 30 April 2024 House of Keys (HOK) sitting, in full. Link: https://tynwald.org.im/audio?file=/business/listen/AgainFiles/k240430a.mp3
Question 13: recorded run time between: 1hr 35:48 and 1hr 40:15 of the sitting. (NB: you may need to download this audio file to access the recording in full, due to current streaming issues, as noted on the Tynwald website).

This HOK answer did note that the wind turbines would not be operational during very low and very high wind speeds at the site. During such conditions, turbines are not turned off but they do cut-out to protect the assets, and in practice they are not operated above this cut-out to avoid any degradation in life-expectancy.

To provide further advice, our website FAQ’s does state that part of the Environmental Impact Assessment process was also to allow for Manx Utilities ‘to gather accurate wind speed data to ensure our turbine design will withstand the most extreme wind speeds at the sites.’.

Please quote the reference number 3843609 in any future communications.

Your right to request a review

If you are unhappy with this response to your freedom of information request, you may ask us to carry out an internal review of the response, by completing a complaint form and submitting it electronically or by delivery/post.

An electronic version of our complaint form can be found by going to our website at https://services.gov.im/freedom-of-information/Review . If you would like a paper version of our complaint form to be sent to you by post, please contact me and I will be happy to arrange for this. Your review request should explain why you are dissatisfied with this response, and should be made as soon as practicable. We will respond as soon as the review has been concluded.

If you are not satisfied with the result of the review, you then have the right to appeal to the Information Commissioner for a decision on; 1. Whether we have responded to your request for information in accordance with Part 2 of the Freedom of Information Act 2015; or 2. Whether we are justified in refusing to give you the information requested.
In response to an application for review, the Information Commissioner may, at any time, attempt to resolve a matter by negotiation, conciliation, mediation or another form of alternative dispute resolution and will have regard to any outcome of this in making any subsequent decision. More detailed information on your right to a review can be found on the Information Commissioner’s website at www.inforights.im. Should you have any queries concerning this letter, please do not hesitate to contact me. Further information about freedom of information requests can be found at www.gov.im/foi. I will now close your request as of this date.