Data for Tonn Nua offshore wind auction

Data is critical to advancing Irelands renewable energy goals and securing its energy future. Ireland has ambitious offshore renewable energy targets and the meeting of these targets' hinges on comprehensive data and surveys to assess site feasibility, environmental impacts, and logistical considerations. Geophysical survey data is required to determine the bathymetry, assess the seabed and sub-bottom conditions, identify seabed including soil type and sub-bottom geohazards and terrain models. Geophysical surveys may also inform optimal placement of turbines.

Ireland's second offshore wind auction will take place in the Tonn Nua auction site, off the coast of County Waterford. The auction bidding process is expected to take place in 2025.

The Department of the Environment, Climate and Communications (DECC) has now made critical geophysical data sets available for the Tonn Nua auction. These datasets will support prospective auction participants in their analysis to better inform and de-risk bid preparations.

Tonn Nua will be the first offshore auction to be held within the South Coast Designated Maritime Area Plan (SC DMAP). Along with the Tonn Nua auction site, the SC DMAP identifies four maritime areas off the south coast in which ORE development will take place over the next decade. All four maritime areas are located off the Cork, Waterford and Wexford coast. This approach offers further certainty to ORE developers – by ensuring that future ORE windfarm developments will be led by maritime spatial plans identified by Government and approved by the Oireachtas. It also protects the marine environment and supports citizens reliant on the sea.

Following a 6-week public consultation, the Department of the Environment Climate and Communications, through the Marine Institute, mobilised the research vessel the Tom Crean to conduct a geophysical survey within the SC DMAP. This survey ran from 6 July 2024 until 12 September 2024. Geophysical data from both the Tonn Nua and Lí Ban sites was collected.

Data deliverables being made available as part of the final data drop for the Tonn Nua site from the recent Marine Institute and DECC geophysical surveys includes the following:

• Administration Data to include:

o Technical note describing data content

o Survey mobilisation and calibration report

o Survey field operations report

o Survey logs and metadata

• Raw multibeam data
• Processed multibeam bathymetry and backscatter grids
• Sub-bottom profile data (raw data files and processed SEGY data)
• 2D multi-channel Ultra-high Resolution Seismic (raw SEGD data, QC Brute Stacks and Processed SEGY data)
• P190 navigation data, and CMP depth information (extracted from the levelled multibeam surface) to facilitate UHRS data processing
• GIS Layers, including sensor track-lines, production overview and boundary shapefiles

As a result of a request for tender for the provision of 'Legacy marine data and rights to publish legacy marine data for the South Coast DMAP', DECC has procured an existing geophysical dataset which overlaps with the intended site for the upcoming Offshore Renewable Electricity Support Scheme (ORESS) Tonn Nua auction.

Data deliverables being made available as part of the third data drop for the Tonn Nua site from the procured geophysical surveys includes the following:

Multibeam Echosounder – Bathymetry

The Multibeam Echosounder (MBES) Bathymetric data acquired within the South Coast DMAP, Tonn Nua area is designed to be of IHO Special Order accuracy.

Raw data formats:

• Qinsy MBES database files (*.DB)

Processed data formats:

• Geotiff raster at 1m resolution (*.tiff)
• Gridded XYZ at 1m resolution (*.XYZ)

Side Scan Sonar (SSS)

Side Scan Sonar (SSS) data was acquired using an independently towed, industry standard Edgetech 4205 Dual Frequency sensor.

Raw data formats:

o Edgetech Discover proprietary files (*.JSF)

Processed data formats:

o Geotiff raster SSS mosaic at 0.5m resolution (*.tiff)

o Processed files (*.jsf)

Magnetometer (MAG)

Magnetometer (MAG) data was acquired using an independently towed, industry standard Geometrics G882 magnetometer sensor.

Raw data formats:

o Raw Magnetometer data in text format (*.txt)

Processed data formats:

o Processed Magnetometer files (*.csv, *.txt)

o Magnetometer anomaly targets (*.csv, *.shp)

o Tracklines (*.shp)

This data is approximately 140GB in size.

To access this data please see below.

DECC has procured a metocean characterisation report and data package with the objective of establishing a detailed meteorological and oceanographic (metocean) model to characterise the prevailing metocean conditions of the SC-DMAP area and four maritime areas, which will serve as vital input for safe and cost-efficient design, installation, and operation for developers, ports and governmental/regulatory authorities. Long term (40 years) hindcast time series data of modelled metocean conditions from the SC-DMAP area (consisting of wind, water levels, current speeds and surface waves) are provided, as input data, for statistical analyses and assessments of operational and extreme metocean conditions that are to be expected across the SC-DMAP area.

A summary of the deliverables produced are as follows:

1) Winds

a) Wind statistics, including mean and maximum wind speeds and directions at 10 mASL in the 40-year ERA5 dataset, and also for a nominal hub height of 150 mASL. Mean wind speeds are available at 1-minute, 10-minute and 1-hour averages, and wind speed standard deviation at these respective averaged intervals are also available. These data are provided in CSV and GeoTIFF format.

b) Omni-directional wind extremes for 1-, 10-, 50- and 100-year return periods for wind speed at 10 mASL and 150 mASL, available at 1-minute, 10-minute and 1-hour averaged intervals, as well as maximum wind speed averaged over 3-second interval (3 second gust), are also provided. These data are provided in CSV and GeoTIFF format.

2) Waves

a) Wave statistics, including mean Hs, maximum Hs and Hmax, from the 40-year hindcast, are provided in CSV and GeoTIFF format.

b) Omni-directional wave extremes for 1-, 10-, 50- and 100-year return periods for wave height (Hs, Hmax) and the associated wave periods (Tp, Tz, Tm01), are provided in CSV and GeoTIFF format.

3) Water Levels

a) Water Levels statistics, including maximum tidal range, MSR, MNR, MHWS, MLWS, MHWN, MLWN, HAT, LAT, maximum and minimum water level, and maximum surge, are provided in CSV and GeoTIFF format.

b) High water and low water level extremes, and positive and negative extreme surge, for 1-, 10-, 50- and 100-year return periods, are provided in CSV and GeoTIFF format.

4) Currents

a) Currents statistics, including maximum flood and ebb tide current speed (depth averaged and near-bed), maximum flood and ebb tide current direction, and maximum surge current speed in the 40-year hindcast, are provided in CSV and GeoTIFF format.

b) Omni-directional current extremes for 1-, 10-, 50- and 100-year return periods for depth-averaged current speeds, are provided in CSV and GeoTIFF format.

5) Weather Window Analysis

a) Monthly and overall percentages of non-exceedance for specified metocean conditions and durations are provided. These data are provided in CSV format for all sample points within the SC-DMAP area, and Tonn Nua site, as part of the accompanying data package. Additionally, select conditions have been extracted into GeoTIFF format.

6) Joint Probability

a) Joint probability (%) of certain metocean parameters, Hs vs. Tp and Hs vs. Tp vs. Uw are provided. These data are provided in CSV and PNG format for all sample points within the SC-DMAP area, and Tonn Nua site, as part of the accompanying data package.

• A first 'data drop' was made available on 7 November 2024
• A second 'data drop' became available at the end of December 2024
• The third 'data drop' became available on 26 March 2025

Both processed and unprocessed data has been made available, however, no interpretation has been applied to the data. New users are asked to please complete the data request form and data license agreement which are available below and send them to oefd@decc.gov.ie. DECC will send the data to users through an Azure Solutions link once these documents have been returned to DECC. Users can expect 1.5 TB of data from the data drop, once the files have been extracted.

For any queries regarding this matter, please contact: oefd@decc.gov.ie