e-Newsletter - First issue - July 2008
Implemented by a European consortium (Spain, UK, Greece) led by the Energy Agency of the Basque country (EVE), NEREIDA MOWC will demonstrate the viability of integrating a wave energy collection system in the new breakwater under construction in the town of Mutriku (Spain)
NEREIDA MOWC is the first:
… Demonstration of an integrated wave energy collection system in a breakwater.
… Application of multiple small breakwater Wells turbines
… And only shoreline wave energy device accessible from continental Europe
In this issue:
N NEREIDA MOWC: Innovation and Demonstration as key words - N The project as of today - N Technological corner: testing, testing - N Around the project - In brief: Facilitating replicability and market introduction; High level visit to the Mutriku plant; Fighting the Mutriku dragon
NEREIDA MOWC: Innovation and Demonstration as key words
The origin
of the project dates back a few years, when the Basque government’s
General port office consulted the Basque Energy Board
(EVE – Ente Vasco de la Energía) about the possibility of harnessing
energy in the breakwater that they were in charge of building in the
small town of Mutriku (pop 4.800 inhab.), an urban area located in the
North of Spain, on the Atlantic ocean’s shore, with a long seafaring
and fishing tradition.
Following relevant studies it was decided to install a multi-chamber system, making the Mutriku facility the first breakwater in Europe to integrate this technology and adopt this design arrangement. Another unusual feature of the Mutriku facility is that it will be integrated into a rockfill breakwater, requiring a new technique for building the structure.
The plant will consists of 16 oscillating water columns (OWCs)or chambers, forming a total collector length of approximately 100m, in which 16 Wells turbines will be installed (one per OWC). Each turbine will have a rated capacity of 18.5 kW, giving a total installed capacity of 0.3 MW. The facility will also contain control and power conversion equipment, a transformer and a line connecting to the power grid.
The plant will be supplied turnkey by Voith Siemens Hydro, Tolosa. The technology is being developed by Wavegen, also a member of the Voith-Siemens group. The plant has an anticipated annual production capacity of 600,000 kWh—equivalent to the domestic power consumption of 600 people.
As an innovative demonstration project, Mutriku project has been selected by the European Commission to receive funds under the Sixth Framework Programme.
Besides the technology and energy objectives, NEREIDA MOWC will also assess the environmental impact and economic aspects of the plant, and develop a business plan for the further development of Oscillating Water Columns (OWC) in breakwaters in Europe (see below: an economic study).
Demonstrating the technological and economical feasibility, the NEREIDA project will be a first step towards market introduction of OWC technologies.
At present, the plant's civil works are almost finished. The breakwater is almost completed and the room where the turbines will be located is ready. It is expected that the partial reception of the works will take place at the end of the summer period. The next step will be installation of the turbines. This part of the work is due to start on September 30th. This phase will be completed within 6 months, after which the test phase will begin, by the end of 2008 or early 2009.
The picture on the left shows the current advancement of the work.
Technological corner: testing, testing
The success of the NEREIDA MOWC project is critically dependent upon the design of the turbo-generation plant. Therefore, Wavegen, the partner company in charge of the technological development of the plant, in co-operation with the two Spanish partners of the consortium, has put considerable effort into testing in order to determine the right turbine system, first, and then to improve the design.
Finding the right turbines
For this first step, a model of a section of the Mutriku breakwater was built and tested in the Wavegen wave test tank. Wavegen worked with the Basque Government Department of Transport and Public Works, their consultants and Ente Vasco de la Energía (EVE) to determine the final geometry for the chambers to be incorporated into the new breakwater.
Based upon the pneumatic powers measured during wave tank tests and the variation in average power throughout the year a solution using 16 x 18.5kW Wells turbines was selected as most suitable for incorporating into new outer breakwater at Mutriku.
The wave tank test results coupled with results from Wavegen’s numerical models were used to determine the turbine size and hub/tip ratio and other characteristics such as the blade profile, the number of blades, the solidity, the operating speed and the number of turbine rotors.
Speed, noise and reliability: design improvements
To maximise the electrical output of Wells turbines, it is desirable to run the turbine as fast as possible. In practice however, ignoring mechanical constraints, there is a limit to the maximum speed, for example, noise generation, bearing life and shock wave formation.
For this second step, Wavegen has manufactured five generations of Wells turbines of the size proposed for the NEREIDA MOWC project. The turbines have been tested at LIMPET, the company’s wave test station on the island of Islay off the west coast of Scotland. The turbines have been tested with different components, instruments, rotors, control mechanisms and strategies, etc.
In late 2007 the design was fixed and manufacture of various components and systems commenced.
For more information, you can visit Wavegen's website.
Facilitating replicability and market introduction
An important objective of the NEREIDA MOWC project is to create the condition for a take off of wave energy - and more specifically OWC technologies - at the European level. Therefore, the project will prepare:
- best practice guidelines: to be developed by Wavegen, addressing, among others the design and erection method, options for the integration of OWC in breakwaters, design, layout and maintenance procedures for the turbines, etc.
- a market study: to be undertaken by the CRES will facilitate the development of that type of installation to be developed throughout Europe. It will include the preliminary identification of possible sites, the review of actual costs for the Mutriku plant and a preliminary economic assessment of the selected sites.
Fighting the Mutriku dragon
As some have already started to call the plant "the Mutriku dragon" out of fear of the noise that would be generated by the plant once in operation, one of the main element for the public acceptance of the project is to demonstrate that the plant will not generate unacceptable levels of noise. Therefore, the selection of appropriate turbine characteristics to minimise noise generation has been a key requirement of the design process. Noise produced by the turbine will be attenuated both at the turbine and where air enters and exits the turbine room to ensure that the noise emitted from the breakwater meets acceptable levels. Besides, information campaigns targeted at Mutriku's citizens have been undertaken, and will continue throughout the project.
Nereida in the press
In November 2007, two Councillors of the Basque Governement, Ana Agirre and Nuria López de Gereñu visited the Mutriku plant, accompanied by the city's mayor, Josebe Astigarraga. Click here to download the press release and related article in the press (Spanish only)
Click on the following links for other articles in the press: noticias de gipuzkoa, www.soitu.es; El Pais (Spanish only)
Nereida Project Leader
Nereida Project Partners
The Nereida MOWC project is supported by the EU 6th framework programme for RTD
Edited by FEDARENE with the support of the partners of the NEREIDA MOWC project partners. Legal Disclaimer: The sole responsibility for the content of this leaflet lies with the authors. It does not represent the opinion of the Community. The European Commission is not responsible for any use that may be made of the information