InternationalFachagentur Nachwachsende Rohstoffe e. V.



Cluster On Anaerobic digestion, environmental Services and NuTrients removAL

The main objective of the COASTAL Biogas project, funded under the Interreg South Baltic Programme, was to promote the uptake of current technology related to anaerobic digestion of cast seaweed in combination with digestate utilisation as means to mitigate eutrophication and reduce nutrients discharges into the Baltic Sea and take a first step towards a circular bioeconomy by closing the nutrient loop.

The project aimed to promote the transfer of low quality resources/wastes into a renewable high quality fuel that can be used for local electricity and heat supply, as transport fuel or for injection into the natural gas grid. In addition, it addressed inconveniences with rotting seaweed on the beaches. Its removal will be for the benefit of recreation, tourism and increase the value of residential properties along the coast.

Another objective of the project was the improvement of the anaerobic co-digestion of cast seaweed and its adaptation to local conditions. The project partners scanned the South Baltic Sea area for current technology development and sites/facilities where co-digestion of cast seaweed and use of digestate as a fertiliser has been implemented.

Based on good practice experiences, the project consortium conducted lab scale testing of seaweed as substrate for biogas plants and assessed what conditions are the most favourable for the anaerobic digestion. The aim was to further improve these processes and to advice concerned biogas operators accordingly.

A decision support tool for biogas operators, municipalities and other interested parties included socio-economic aspects, policies, regulations and directives in order to implement the technology. The strong cross-linking to other relevant large biogas projects in the Baltic Sea area (CONTRA, GRASS, the SUBMARINER Network and Greater BIO) as well as to organisations like the European Biogas Association, HELCOM and the Nordic Council of Ministers ensured the transfer of the project’s results to relevant stakeholders.

The project ended after a duration of 3.5 years in December 2021. FNR was the lead partner and responsible for the overall project coordination. All project results are available on the project website.

Duration: 07/2018 – 12/2021





The project was funded by the Interreg South Baltic Programme, co-funded by the European Union fund ERDF.





The project is funded by the Interreg South Baltic Programme, co-funded by the European Union fund ERDF.