On 4 November an international group of over fifty policymakers, scientists, consultants, and representants of industry and non-governmental organisations came together in Bad Nieuweschans, The Netherlands, to discuss different aspects of the sustainable use of cooling water from the Wadden Sea. During the workshop - organised by the Wadden Academy in cooperation with RWS-Waterdienst and ZiltWater Advies - it became clear that our knowledge on the ecological effects of the large-scale use of cooling water from the Wadden Sea estuaries by power plants is still limited.Currently, the Eemshaven is developing towards an energy cluster in the Dutch Wadden Sea and similar developments are occurring in the German Wadden Sea, near Wilhelmshaven and in the estuaries of Weser and Elbe. If all existing plans will be realised the generated energy and the volume of cooling water that is withdrawn will be doubled. What will this mean for the Wadden Sea?
During the morning session experiences were shared by the responsible Dutch and German authorities. There are few studies on the intake of larval and juvenile fish by the systems. Back-of-the-envelope calculations provide rough estimates of the potential yearly intake but the seasonal variations and the species-specific impact remain largely unknown and the (significant?) effects on fish populations are difficult to quantify.
During the afternoon session, different technology and approaches of reducing the intake of fish were discussed. Considerations of consultants, in advising on the issue of cooling water impact, were presented by a German and by a Dutch consultant. Germany has implemented regulations for the thermal discharge and adequately covered this issue, but the entrainment and impingement of organisms requires attention. There is a variety of technology available to reduce the impingement, but each power station requires a site-specific set of techniques that can be applied.
The requirement that proven technology should be applied can block innovations. During the lunch break two examples of innovative techniques were demonstrated. At the end of the workshop it was suggested that funding opportunities, including the Wadden Fund, could be used to develop innovative techniques and to fill the knowledge gaps.
With respect to the second potential ecological problem, the thermal discharge into the surface waters, modelling studies indicate that water can be heated by several degrees over a large area. This occurs against a background of increasing temperatures by climate change. The cumulative effect of several power stations withdrawing from the same waters are unknown and its impact on the ecosystem needs further study.
At the end of the afternoon session, Electrabel presented the adaptations that have recently been made at the Eems power station to return the impinged fish to the environment.
The plenary discussion at the end of the day was started by a panel, consisting of Peter Henderson (PISCES), Aart Verstegen (RWS-NN) and Manfred Vollmer (Wadden Sea Forum). Overarching food for thought was provided by the chair of the day, Prof. Peter Herman (Wadden Academy/NIOO) who questioned whether large power plants, which generate a surplus production of energy, should be located next to the Wadden Sea - being a rich but vulnerable ecosystem with different functions for fish and birds and nominated UNESCO World Heritage site since 2009.