Marine Energy Resource
Ireland's offshore marine energy resource is considered substantial by European standards and there is significant potential in harnessing these resources to generate electricity.
- Peak Period
- Upcross Period
- Peak Direction
- Significant Wave Height
Observations of waves are collected from the Weather Buoy Network buoys M2, M3, M4 and M6 which include:
- Significant Wave Height
- Wave Period
- Max Wave Height
- Max Wave Period
- Mean Direction
Marine Institute Oceanographic Services provide wave modelling support to the Ocean Energy Industry via the SWAN wave model producing weekly forecasts. The numerical wave model, SWAN, is run for a 0.025 degree grid every weekday to produce a 6 day forecast. The model uses NCEP GFS for wind forcing and FNMOC Wave Watch 3 data for the wave boundaries. The forecast is generated for research purposes and for comparison with measured wave parameters. The Marine Institute does not guarantee to make model output available on its web site. The predictions should not be used for safety critical applications.
The SWAN wave model produces forecast data on:
- Wave Height and Direction
- Wave Period and Direction
- Wind Speed and Direction
In addition, the modelling team produce "Monthly Model Means" of significant wave height, mean wave direction and mean wave period.
The atlas published in 2005 describes an initial comparison between several years of hourly wave forecasts (using WAM) on a grid of points located off the Irish coast with corresponding records from a number of buoys installed in recent years. Based on the level of agreement found the wave forecasts were then modified slightly and used to estimate and map the mean annual power and energy resources at the theoretical, technical, practicable and accessible levels.
Data in the map gallery produced by the “Wave Atlas” consists of wave estimates generated by the Pelamis model including:
- Annual Average Wave Height (m)
- Annual Average Wave Period (s)
- Annual Average Power Practicable (MW)
- Annual Pelamis Energy (MW)
- Seasonal Average Power Flux kW (kW)
- Seasonal Hydro Energy MW hours (MW)
- Seasonal Pelamis Average Power MW (MW)
- Seasonal Pelamis Energy GW hours (GW)
Ireland's offshore wind resource is considered substantial by European standards and this potential is being realised by the existing installation of the Arklow Bank Wind Park in the Irish Sea as one of the World's first offshore wind parks.
Offshore wind speeds have been mapped to a distance of 25 km from the Irish coast. The wind resource displayed has been constrained to exclude areas where wind energy projects will not be permitted such as areas where seabed cables and gas pipelines are located, indicative navigation channels, Department of Transport traffic separation and exclusion zones, Department of Defence Danger Areas and near-shore anchorage area.
The Wind Atlas can assist with the offshore wind planning process and act as a data resource to developers and policy makers alike.
The wind maps show the predicted mean wind speed at a heights of 50 m – 100 m above ground level and the predicted mean wind power density at the same heights. The mean speed and power describe different aspects of the wind resource, and both can be useful in different ways. The mean speed is the easier for most people to relate to and is consequently the more widely used. However, it does not directly measure the power-generation potential in the wind. Some experts regard the mean wind power, which depends on the air density and the cube of the wind speed, as a more accurate indicator of the wind resource when assessing wind project sites. Generally speaking, commercial wind power projects using large turbines require a mean speed of at least 7 m/s or mean power of at least 400 W/m2. Small turbines are designed to operate at lower wind speeds, and may be useful at mean speeds (at 30 m height) as low as 5-6 m/s.
The Sustainable Energy Authority Ireland conducted a study to identify the potential for cost effective exploitation of the tidal stream and marine current energy resource and to prepare detailed analysis of areas considered to have the greatest potential for the extraction of tidal energy. This report considers a calculation of the tidal and marine current energy resource available with existing technology and to assess the additional contribution which future technology is expected to make. The report evaluates deep water areas (exceeding 40m) which have high current velocities for the purpose of developing second-generation deep water devices. The report extends the methodology for estimating the renewable energy resource in Ireland to provide a medium term development potential (or estimated contribution) for the years 2010 and 2020, including the anticipated resource/cost curve per unit of energy produced.
The tidal currents are generally low along the west and south coasts, are relatively strong in the St George’s and North Channels and are moderate along much of the east coast. The current strengths are considerably influenced by the local bathymetry. One part of the flood travels up the west coast and around the north of Ireland, whilst the other part floods north up the Irish Sea. The tidal streams meet in the area of St John’s Point. A consequence of the way the tides flow around Ireland is that there is a phase difference in the times of high and low water along different parts of the coast.
- A significant proportion of the tidal and marine current energy resource is to be found on the east coast of Ireland. The resource on the west coast is concentrated in the Shannon Estuary.
- Tidal energy technology is in the early stages of development and stream velocities of at least 2.0m/sec are required for efficient generation. With further technological development, efficient
- generation from stream velocities of 1.5m/sec should be practicable by the year 2015.
- When technical, physical, institutional and commercial viability constraints are applied the resultant energy resource, referred to as the Viable Resource, reduces to approximately 0.915 TWh/year and this represents 2.18% of the predicted electricity consumption for the year 2010. This figure could rise to 6.27% of the predicted electricity consumption between 2010 and 2015.
- Environmental constraints, specific to each site, may also apply and in such cases exploitation of the viable resource may be affected.
- Many devices are in their infancy as development remains at an early stage. Largely due to commercial confidentiality, detailed information on test results is not widely available.
- A re-assessment of generating viability after a period when further test data should be available is recommended.
Marine Institute HQ Sustainable Energy Authority Ireland
Rinville, Wilton Park House
Oranmore, Wilton Place
Co. Galway, Dublin 2
Tel: +353-91-387200 Tel: +353-1-8082100
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