Are landfall cable cooling systems part of the solution to reduce the costs of offshore wind?

Worldwide, the offshore wind capacity is expected to grow from approximately 60 GW to 350 GW by 2030. Achieving this goal has its own challenges, one of them being the cabling system carrying the electricity from sea to land.

According to Offshore Wind Accelerator (OWA), a research programme initiated by UK’s Carbon Trust in partnership with Ørsted, Equinor, SSE Renewables, Scottish Power Renewables, Shell, Vattenfall, RWE, Total Energies, and EnBW, the cost of cable supply and installation for wind farms typically accounts for 8-12% of overall capital expenditure (CAPEX) costs and cable-related incidents account for 80% of insurance claims for offshore wind farms.

Improving the reliability of the cabling system, especially when higher amounts of electricity are expected to enter the grid in the following decade, is crucial to reduce the overall costs of an offshore wind farm.

The cables technical group, one of the five technical working groups under OWA consisting of experts from the partner organisations, has appointed Ramboll to carry a study on the practicability of using cable cooling systems at landfall.

“We are delighted to enter this flagship partnership and contribute with our submarine cable expertise on a topic that is very little researched.

Landfall cooling systems have the potential to cut the overall CAPEX of offshore wind farms by simply increasing capacity rates and subsequently omitting any revised cable specification in the landfall section. It is a learning journey for all of us and we are excited to see what the findings will be”, says John Ammentorp, country market director at Ramboll.

At landfall locations where horizontal drilling is used, the cables are typically enclosed and highly insulated to protect them from wave impact and erosion. This increases the risk of overheating and limits the electricity capacity. Landfall cooling systems can absorb the heat form the cable, allowing for a better electricity flow and reduced bottlenecks.

A detailed study that will develop into an industry guideline

The main objective of this study is to increase current throughput, establish the level of feasibility and analyse practicability, including potential associated risks. Furthermore, this study aims to investigate any potential electricity rating improvement associated with using a landfall cooling system.

Ramboll will perform a feasibility study, identifying different landfall cooling system designs and analysing equipment costs, operation and maintenance, consenting issues and associated risks. In detail, this includes thermal conditions, the need of monitoring the cooling system, the cost of constructing, installing, operating and maintaining the technology, as well as the environmental impact of the installation.

As there is very little research related to landfall cooling systems, Ramboll’s learnings and findings will be developed into a guideline that will serve the industry going forward.