Search cables; authorities
The seabed in fjords and harbors is part of the territorial sea and subject to state sovereignty.
A port thus has "right of use" to the water, but any permission to make changes to the territorial waters must generally be approved by the Danish Coastal Authority. The Danish Coastal Authority's administrative basis for pipelines is described in section 5.3.1, on p. 80f here.
However, the Danish Energy Agency is the authority for laying electricity cables and oil and gas pipelines in the seabed, and the Danish Nature Agency for raw material extraction on the seabed.
Submarine cables must be registered in the cable owner register (LER) and disclosed in "Notices to Mariners". In addition, in some cases, an EIA report may also need to be prepared according to the authorities' instructions.
A port is not an authority in relation to pipes in the harbor basin, but since laying pipes will probably mean that the sheet pile or quay wall must be breached, the port must approve this.
The "guest principle" is the term for a supplementary rule that applies in cases where permission has been granted to install a pipeline on a property without payment. The rule means that the pipeline owner as a "guest" must pay for pipeline works that are necessitated by the landowner's changed use of the area where the pipeline is placed. As far as we know, there is no case law that has ruled on whether the guest principle also applies to cables in territorial waters. However, it is assumed that this is the case.
The bill on the construction of Lynetteholm is based on the assumption that the guest principle also applies to the territorial waters. A draft of the bill has been subject to ministerial consultation in the Ministry of Justice and for legal technical review, but the Ministry of Transport has not explicitly requested the Ministry of Justice's assessment of the issue, which is why it will ultimately be up to the courts to assess this.
The guest principle must thus be assumed to apply to the territorial sea and mean that changes in the port that result in submarine cables having to be moved or removed later entail that the cable owner must bear the costs of this.
The legal basis has not been investigated further, but it should probably be considered whether it is appropriate/defensible to lay cables or pipes in a commercial harbor basin that is continuously cleaned and jacked up.
The above is a general statement and if specific decisions are to be made, it will need to be investigated further.
