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Contact:

Jose Ramón Epelde

Ente Vasco de la Energia

Contact details:

jrepelde@eve.es

(+34) 94.403.56.00

2005/2/4

Construction of the first plant for using energy from sea waves

The municipal borough of Mutriku on the Basque coast has been chosen as the location for the first plant in the Basque Country for the generation of electricity, taking advantage of the energy produced by sea waves. The plant is to be installed at the outside of the new containment dyke to be built at the Port of Mutriku. The Department of Transport and Public Works of the Basque Government will be responsible for civil engineering and the Basque Energy Authority, EEE, for the energy installation. This project represents a great advance in the use of renewable energies as it provides a resource which has not been utilised to date in the Basque Country.

It involves the installation and putting into operation of a maritime plant for the production of electrical energy by means of using the sea waves on our coasts.

The plant will be installed outside the new containment dyke to be built at the Basque port of Mutriku. The power of the installation will be 480 kW, which means that the energy generated annually will be 970 MWh, which will mean avoiding the emission of approximately 1000 tons of CO2 into the atmosphere – the contamination produced if this same energy were to be produced using fossil fuels.

Unique installation

The system chosen for the energy installation at the Mutriku containment dyke has aspects that make it unique amongst renewable energy projects to date. The technology used is known as oscillating water column (OWC), which is currently the most developed technique for the optimum use of wave energy. A multi-turbine arrangement has been chosen - concretely one with 16 turbine-chamber units - in order to achieve better integration of the plant into the dyke.

In the world at present there are only two prototype-level installations which are using this technology for exploiting energy from waves: in Scotland and in the Azores. Nevertheless, the installation at Mutriku will be the first on the planet with more than one turbine.

Likewise, it is the first installation in the world that will be totally integrated into a newly built dyke. The electric energy produced will be sold in its entirety to the national electricity grid, being the first within the peninsula and, indeed, in continental Europe, to do so. In this way, it has the advantage of producing clean energy and avoiding generating the same quantity of energy from contaminant energy sources.

The operation of an OWC for exploiting sea wave energy is simple and totally innocuous for the surrounding environment. On the wave arriving, the layer of water rises in the inside of the turbine chambers, compressing the air inside and expelling it through a small aperture located in the upper part. This causes the compressed air to be expelled at great speed, in turn making the turbines rotate. Thus, it is the compressed air that turns the turbines, not the seawater directly. The electric generators connected to the turbines produce electrical energy. When the layer of water descends, a vacuum is created inside the chamber, sucking the air in through the upper aperture, causing the turbines to rotate again. The turbines are designed to turn independently of whether the air is expelled or sucked in.

Energy strategy

As regards the target objectives for the development of infrastructures for the exploitation of wave energy, it is hoped to generate an installation power of 5MW by 2010.

Likewise, this project forms part of a series of measures involving renewable energies and with the view to these energy sources providing 12% of the total energy by 2010.

This target is a common one for European policies as well as being in accord with the agreements reached with the Kyoto Protocol.

Energy from the sea

Energy can be extracted from the sea by various procedures, according to the manner in which this energy has been stored. Thus, four types of use are classified: tidal energy, ocean thermal energy, the energy from water currents and wave energy. For each one of these, energy exploitation techniques are being designed that are at different stages of development.

There is no installation currently in the Basque Country that makes use of energy from the sea in any of these procedures. It has to be considered that the potential for energy use that our coast can offer varies considerably depending on the type of use.

Whether ocean thermal energy, tidal energy, or energy from water currents, what the Basque littoral can offer is not sufficient to be used energetically with the technology currently available.

The tidal level differences, however, of less than 5 metres and an average annual energy flow in the order of 30 kW/m that is registered in the Basque Country, make the use of wave energy, with OWC technology, viable.