Aker Offshore Wind included underwater substation in ScotWind floating bid

Developer claims underwater substations could be cheaper and more reliable than those above sea level

Aker Offshore Wind claims underwater substations could be cheaper and more reliable than those above sea level

Aker Offshore Wind has unveiled plans for an underwater substation. It hopes to deploy it at floating offshore wind projects off Scotland, if it is successful in an ongoing leasing round.

Aker Solutions would develop, manufacture and supply the substation in Scotland, creating export opportunities for Scottish companies, the developer explained.

Substations collect and help to export power generated by offshore wind farms, stabilise and maximise the voltage and reduce power losses.

They are usually installed above sea level, but placing them on the seabed could yield several benefits, according to Aker Offshore Wind.

Seawater could be used as a natural cooling system, while stable temperatures, fewer components and the lack of rotating parts could aid reliability, it suggested. Reduced maintenance requirements could also lead to lower operational costs, Aker Offshore Wind added.

Underwater substations would need fewer components than their above-sea-level counterparts because they would not need any auxiliary systems like HVAC (heating, ventilation and air-condition), accommodations for personnel, low voltage systems, generation and distribution, an Aker spokesman explained

They are designed to be maintenance-free, but may require visual inspections to be carried out by remote operated vehicles to check for debris, he added.

Underwater substations are used in the oil and gas sector, albeit on a much smaller scale, the spokesman advised. They have been deployed around the world in places like Australia, the Gulf of Mexico, Africa and the North Sea, with no reported failures.

Aker Offshore Wind included the underwater substation as part of its bids with Ocean Winds in Scotland’s offshore wind leasing round. The pair had submitted a series of bids for sites that could support up to 6GW of floating offshore wind capacity in the Outer Moray Firth, off Scotland’s north-east coast.

Scotland’s offshore wind leasing round closed for submissions in July, after several bids were filed by offshore wind and energy giants. Auction regulator Crown Estate Scotland is expected to announce the results in early 2022.