It is mandatory for all market participants under REMIT to register with the national regulatory authority in the Member State in which they are established or resident. If the entity is not established or resident in the EU – but included under REMIT – the entity shall be registered in a Member State in which they are active.
A market participant shall register only with one national regulatory authority. This also applies for market participants active in several Member States.
The registration is on entity level meaning that if more legal entities within a group are included under REMIT, each legal entity should be registered e.g. subsidiaries.
Go to Ofgem’s page here (UK)
Go to Bundesnetzagentur’s page here (DE)
Go to Energimarknadsinspektionen’s page here (SE)
Go to Energitilsynet’s page here (DK)