The Blue Farm is a floating concrete cage collar with tension anchoring to the seabed.
The cage is kept afloat by a nearly six-metre-high double ring structure, called a “double tower”. This can be ballasted and deballasted in connection with the connection of tie rods.
A walkway will be built five metres above the water level inside the ring and extends around the entire cage. The walkway is protected by a 2.16-metre wall that is integrated into the structure.
The cage also contains three or four integrated function houses that will provide space for storing feed, dead fish, facilities for operators and a workshop / engine room.
Grieg applied for ten development permits – equivalent to maximum permitted of biomass of 7,800 tonnes – in November 2016.
In December 2017, the Directorate told Grieg that based on the available information the concept appeared to meet conditions for development licences but requested more documentation.
In October 2018 it rejected the application after reviewing new documents, but that decision has been overturned on appeal. The Directorate has granted Grieg three development permits for a total of 2,340 tonnes of biomass.