Ocean energy

The oceans contain a huge amount of energy. Changes in salinity, thermal gradients, tidal currents or ocean waves can be used to generate electricity using a range of different technologies. These could provide reliable, sustainable and cost-competitive energy. Capturing ocean energy could have substantial benefits.

The energy in the ocean waves is a form of concentrated solar energy that is transferred through complex wind-wave interactions. The effects of earth’s temperature variation due to solar heating, combined with a multitude of atmospheric phenomena, generate wind currents in global scale. Ocean wave generation, propagation and direction are directly related to these wind currents. On the other hand, ocean tides are cyclic variations in seawater elevation and flow velocity as a direct result of the earth’s motion with respect to the moon and the sun and the interaction of their gravitational forces. A number of phenomena relating to earth rotational tilt, rate of spinning, and interaction among gravitational and rotational forces cause the tide conditions to vary significantly over time. Tide conditions are more apparent in coastal areas where constrained channels augment the water flow and increase the energy density.

via OES Ocean Energy

The development of wave and tidal resources as a source of energy is the subject of growing international investigation. Ireland’s offshore renewable energy resources have significant development potential and are considered as being among the best in the world, with the practicable wave energy resource estimated at more than 6000MW.

At present there is no well-established wave energy industry anywhere in the world. Ireland has the potential to become a world-leading developer and manufacturer of the technologies that will enable the harnessing of ocean energy resources. To achieve this, the Marine Institute is working with Sustainable Energy Authority Ireland to implement a National Strategy for Ocean Energy. The main objectives are the creation of a centre of excellence in OE technology and the stimulation of a world-class industry cluster and the connection of 500MW of ocean energy by 2020.

via Irish Marine Institute

Finally, an example showing the peak wave power in Galway Bay, obtained using a Spectral Wave Model in summer storm conditions, made using DHI MIKE Coupled Models. If on average wave power is above 30kW/m, energy generation is viable.