Harnessing the Power of the Ocean

In Ireland, we have an abundant wave energy resource thanks to our unique position at the Atlantic edge of the EU and favourable climes. As such, ocean energy has the potential to play a key role in our renewable electricity supply of the future.

 

Ocean energy refers to the energy carried by ocean waves, tides, salinity and ocean temperature differences.

The movement of water in the world's oceans creates a vast store of kinetic energy, or energy in motion. This energy can be harnessed to generate electricity to power homes, transport and industries.

There are three primary forms of Ocean Energy.

Wave Power

Waves are formed by winds blowing over the surface of the sea. The size of the waves generated will depend upon the wind speed, its duration, and the distance of water over which it blows (the fetch), bathymetry of the seafloor (which can focus or disperse the energy of the waves) and currents. The resultant movement of water carries kinetic energy which can be harnessed by wave energy devices.
The best wave resources occur in areas where strong winds have travelled over long distances. For this reason, the best wave resources in Europe occur along the western coasts which lie at the end of a long fetch (the Atlantic Ocean). Nearer the coastline, wave energy decreases due to friction with the seabed, therefore waves in deeper, well exposed waters offshore will have the greatest energy.

Tidal Power

Tidal streams are created by the constantly changing gravitational pull of the moon and sun on the world’s oceans. Tides never stop, with water moving first one way, then the other, the world over. Tidal stream technologies capture the kinetic energy of the currents flowing in and out of the tidal areas. Since the relative positions of the sun and moon can be predicted with complete accuracy, so can the resultant tide. It is this predictability that makes tidal energy such a valuable resource.
The highest (spring) tidal ranges are generated when the sun, moon and earth are in line. Water flows in greater volumes when attracted by this combined gravitational pull. The lowest (neap) tidal ranges are generated when the sun, moon and earth describe a right angle. The split gravitational pull causes water to flow in lesser volumes.
Tidal stream resources are generally largest in areas where a good tidal range exists, and where the speed of the currents are amplified by the funnelling effect of the local coastline and seabed, for example, in narrow straits and inlets, around headlands, and in channels between islands.

Wind Power

Much like onshore wind energy, offshore wind energy provides a clean, sustainable solution to our energy problems. It can be used as an alternative to fossil fuels in generating electricity, without the direct emission of greenhouse gases. As there will always be wind, it is inexhaustible and renewable.

By 2030 Wave Energy Converters will be converting the power of ocean waves to electricity, in Wave Energy Farms located along Ireland’s west coast. The accessible wave energy resource off our coast is estimated to be 21 TWh which would be sufficient to supply 75% of the Republic of Ireland’s annual power demand.

The ESB Westwave project is an exciting 5 MW wave energy project currently being developed near Doonbeg in Co Clare. This will be the first wave farm in Ireland with power expected to start generating in 2018.

ESB is collaborating with Irish universities and research teams including University College Dublin (UCD), National University of Ireland, Galway (NUIG) and University College Cork (UCC) on innovative wave measurements and models.