Submarine AC power line between Sweden and Denmark
The Bornholm Cable is a submarine power cable under the Baltic Sea, connecting the power grid of the Danish island of Bornholm to the Swedish power grid owned by E.on with a capacity of 60 MW.[1] It is owned by Energinet,[2] previously by Östkraft.[3]
There is an agreement between Svenska kraftnät and Energinet about balancing the Bornholm grid.[2]
Cable sections
The cable sections are:[4]
- Hasle substation to Bornholm coast: 1.4 km underground, 400 mm2 conductors at 60 kV
- Undersea section: 43.5 km, 240 mm2 conductors at 60 kV
- Swedish coast to cable terminal: 700 m underground, 400 mm2 conductors at 60 kV
- Cable terminal to Borrby substation: 4.2 km overhead line with 127 mm2 conductors at 60 kV
- Borrby substation to Tomelilla substation: 132 kV line with two circuits
Outages
The undersea section has been repeatedly damaged: in 2004,[5] in 2010[6] and in 2013.[7][8][9] The damage in 2013 cost half a million Danish crowns per day, due to electricity price differences between Bornholm and southern Sweden and the costs of two ships waiting for calm weather to repair the cable.[7]
Reserve generating capacity for when the cable is out of service is provided by coal power plants on Bornholm and by diesel generators to cover the start-up time of the coal plants.[6] There is also a project using energy stored in electric vehicles as a backup supply for a period of hours.[10]
In 2018 the cable was buried deeper in the seabed to prevent damage,[11] but suffered failure due to a dragging ship anchor in early 2022.[12]
See also
References