| Austria | Tyrol | Region |
| Belgium | Flanders | Region |
| Belgium | West Flanders | Region |
| Bulgaria | Bulgarian Ports | Authority |
| Bulgaria | Sofia | City |
| Croatia | Split | City |
| Croatia | Split-Dalmatia County | Region |
| Czech republic | Trutnov | City |
| Denmark | Guldborsund | Municipality |
| Denmark | Lolland | Municipality |
| Estonia | Talinn | City |
| Finland | Kokkola | City |
| France | Auvergne-Rhône-Alpes | Region |
| France | Association Phyrennees- Region of Occitanie | Authority |
| France | Bourgogne Franche Comte | Region |
| France | Centre-Val de Loire | Region |
| France | Grenoble-Alpes Metropole | City |
| France | Normandy | Region |
| France | Orleans | City |
| France | Pays de la Loire | Region |
| France | Pays de St Gilles | Municipalities community |
| France | Roche-sur-Yon Agglomération | Region |
| Germany | Baden-Wurttenberg | Region |
| Germany | Bremerhaven | Region |
| Germany | Hamburg | City |
| Germany | Heide | Region |
| Germany | HyCologne- Hydrogen Region Rhineland | Region |
| Germany | HYPOS Hydrogen Power Storage & Solutions East Germany | Authority |
| Germany | Kreis Steinfurt | Region |
| Germany | North Rhine Westphalia | Region |
| Germany | Recklinghausen | Region |
| Germany | Saxony- Anhalt | Region |
| Greece | Agia Paraskevi | Municipality |
| Greece | Alimos | Municipality |
| Greece | Crete | Region |
| Greece | Heraklion | Municipality |
| Greece | Ierapetra | City |
| Greece | Kalymnos | Municipality |
| Greece | Kozani | City |
| Greece | Milos | Island |
| Greece | Papagou-Holargos | Municipality |
| Greece | Vrilissia | Municipality |
| Greece | Western Macedonia | Region |
| Iceland | Reykjavik | City |
| Italy | Favignana | City |
| Italy | Lazio | Region |
| Italy | South Tyrol | Region |
| Italy | Toscana | Region |
| Italy | Turin | City |
| Italy | Venice | City |
| Latvia | Riga | City |
| Netherlands | Assen | City |
| Netherlands | Drenthe | Province |
| Netherlands | Emmen | City |
| Netherlands | Groningen | City |
| Netherlands | Helmond | City |
| Norway | Akershus | Region |
| Norway | More and Romsdal | Region |
| Norway | Oppland | Region |
| Norway | Sogn og Fjordane | Region |
| Portugal | Médio Tejo | Region |
| Portugal | Torres Verdas | Municipality |
| Romania | Constanta | City |
| Slovenia | Velenje | Municipality |
| Spain | Aragon | Region |
| Spain | Barcelona | City |
| Spain | Cantabria | Region |
| Spain | Castilla - La Mancha | Region |
| Spain | Murcia | Region |
| Spain | Port of Valencia | Authority |
| Spain | Puertollano | City |
| Spain | Valladolid | City |
| Sweden | Gavleborg | Region |
| Sweden | Mariestad | City |
| United Kindgom | Birmingham | City |
| United Kindgom | Dundee | City |
| United Kindgom | Perth and Kinross | Council |
| United Kindgom | Swindon and Wiltshire Local Enterprise Partnership | Authority |
| United Kindgom | Tees Valley Combined Authority | Authority |
| United Kingdom | Aberdeen | City |
| United Kingdom | Cornwall | Region |
| United Kingdom | Fife Council | Region |
| United Kingdom | Leeds | City |
| United Kingdom | London - Greater London Authority | City |
| United Kingdom | Manchester Metropolitan University | University |
| United Kingdom | Newcastle | City |
| United Kingdom | Orkney Islands | Region |
| United Kingdom | Oxfordshire | Region |
