OES-Environmental distributes metadata forms (questionnaires) to solicit information from developers involved in environmental monitoring around marine renewable energy project sites around the world. This page provides project descriptions, baseline assessment, post-installation monitoring, and links to available data and reports. Content is updated on an annual basis.

Mutriku Wave Power Plant

Description

This grid-connected plant is integrated within the breakwater at Mutriku harbour. There are 16 air chambers 4.5 m wide, 3.1 m deep and 10 m high (above Lowest Astronomical Tide). A 0.75 m diameter orifice leads to a Wells turbine and electrical generator of 18.5 kW for each air chamber, yielding a total of 296 kW installed capacity.

Location

Bay of Biscay, Mutriku, Spanish Basque Country.

Licensing Information

The legal framework for the processing of electricity generating facilities is included in Royal Decree 1955/2000 and renewable and special regime facilities are further regulated by RD 661/2007.   

Authorities involved in the permitting of this plant were the General Directorate for Energy Policy and Mines of the Ministry of Industry and the General Directorate for Sustainability of the Coast and the Sea of the Ministry of Environment at a national level, the Directorate of Ports and Maritime Affairs (regarding the use of the Port Public Domain) and the Department of Environment of the Basque Country (for environmental authorisation) at a regional level and the Mutriku Town Council at a local level for the Activity and Works licenses. 

The permitting process started in 2006 and finished in 2009, with the granting of the authorisation for using the Port Public Domain.

Project Progress

The idea of adding a wave energy generating plant into the breakwater design began in 2002, just as the consenting procedure for the breakwater was about to be completed. In 2005, the breakwater was allocated with a design that did not include the wave energy generation. This design was later modified to include wave energy converter turbines in 2006. The project began construction in March 2009 at a cost of 2 million euros. It officially opened in July 2011 and has been successfully operating since then. Until November 2021, the Mutriku wave power plant has supplied 2.4GWh of electricity to the grid.  This facility is also available as a test site, providing developers with a unique opportunity to test new concepts for air turbines, generators, control strategies and auxiliary equipment.

Key Environmental Issues

There may be some environmental concerns regarding the existence of the breakwater and changes in sediment transport and flow dynamics, but the oscillating water columns as an extension of the breakwater do not cause any significant difference. Large amounts of noise were produced during a storm in the construction phase of the wave power plant, reportedly heard 3-10 km away, which concerned the local population and were thought to be potentially harmful to the local environment. After the completion of works and during 10 years of operation of the plant, no complaints have been received in this regard. 

Like with other human activities in the marine environment, some environmental impacts were expected during the Mutriku OWC Plant operation phase as well. Among them, the generation of underwater sound during was identified as one of the main expected environmental impacts.

Papers, Reports, Research Studies

Post-Installation Monitoring: Mutriku Wave Power Plant

Stressor Receptor Study Description Design and Methods Results Status
Noise An environmental monitoring program (EMP) was developed by AZTI (www.azti.es) for the monitoring of the underwater sound produced by the Mutriku OWC Plant 2016. This program was funded by the Science, Research and Development Section of the Regional Government (Diputación Foral de Gipuzkoa) Two sampling campaigns were undertaken in 13 sampling stations during summer and winter 2016. In each sampling station a 10 minute sound recording was done and the sound recorded was later processed and analysed No evidences of significant acoustic impact coming from the Mutriku OWC Plant were obtained. Nevertheless some important limitations related with the design of the EMP suggested the development in the future of a more advanced monitoring strategy based on the implementation of a permanent acoustic underwater monitoring station cabled to the Mutriku OWC Plant. Completed
Noise In May 2018 a fixed hydrophone connected by cable to the OWC Plant has been installed by AZTI (www.azti.es) in order to have continuous monitoring of underwater sound produced by the Mutriku OWC Plant. The installation of this station was funded by the Science, Research and Development Section of the Regional Government (Diputación Foral de Gipuzkoa) Fixed iClisten HF 200 hydrophone of Ocean Sonics cabled to the OWC Plant in order to have continuous monitoring of the underwater sound produced by the Mutriku OWC Plant. This station records 1 minute of underwater sound every 15 minutes, 24/24h. No evidences of significant acoustic impact coming from the Mutriku OWC Plant were obtained. Nevertheless, it is necessary to confirm this hypothesis with a better location of the hydrophone. The sensor was extremely affected by flow-noise coming from the waves due to its shallow position in the water column (6 m depth). Data are accessible at https://www.emodnet-physics.eu/Map/platinfo/pigenericdownload.aspx?platformid=372740. Completed
Noise In the framework of the WESE project (http://www.wese-project.eu/) underwater sound emissions were monitored by means of a combination of static, mobile and airborne measurements. Underwater sound was monitored by a combination of static, mobile and airborne measurements. For the static survey, a SoundTrap ST300 HF was moored on the 7th of May 2019 for a period of 41 days.
The mobile survey took place on the 7th of May, the same instrument was deployed at 17 stations around the plant, recording for 5 minutes at each station.

Airborne measurements were made at the same locations and times as the mobile survey, with specific equipment developed by CTNaval. Auxiliary CTD data were obtained to support underwater sound propagation analysis. 		Data available at Data Platform (marendata.eu). Report available at WESE PROJECT (wese-project.eu)




 Completed
Noise In the framework of the SAFEWAVE project (Home - SAFEWAVE PROJECT (safewave-project.eu)) underwater sound emissions were monitored. Static measurements were carried out with 3 SoundTrap ST300 HF devices, moored from the 17th march to the 30th April 2022 at 250m, 300m and 500m east of the power plant. Data and report not yet available. Report will be made available on the project website. Completed
Noise Monitor and reduce the sound levels from the turbines to meet emission standards. A ‘marine’ attenuator was created to reduce the sound outputs. N/A Completed