T
he London Array, sited in the outer Thames Estuary, was the world’s largest operational offshore wind farm when it was inaugurated by David Cameron, the UK Prime Minister, in July 2013. The wind farm consists of 175 turbines and two offshore substations that are capable of generating up to 630MW, enough energy to power nearly half a million UK homes. The desire to build wind farms was driven by the UK government’s policy to cut carbon emission and reduce reliance on imported fossil fuels. This article provides an overview of the project based on the experiences of Nexans Norway in supplying the high voltage subsea power export cables. In 2009, Nexans Norway was awarded the contract for the high voltage subsea power export cables to connect the London Array wind farm to the UK grid. Delivery was scheduled for 2011-2012. The London Array wind farm was being constructed installed approximately 20km off the UK coast, and the entire wind farm field covers a 233 km2 site.
There were several project challenges. The first challenge being that when the contract was signed, the actual cable route was still under investigation. The area contained a considerable amount of wrecks and also unexploded bombs dropped during WW II. Moreover, fishing activities in the area allowed only for a short time frame for
installation of the cable from the shore end, so maintaining the cable delivery schedule became a critical factor. Nexans Norway’s scope of work was the design, manufacture and supply of the power export cables. The submarine composite cables contain one 3-phase power cable and one optical
element of 52 fibres. Four of these were manufactured, each approximately 55km long. The fibre elements provide communication and temperature monitoring services. The project was based on field proven products, but tailor made to the specific demands of the application, such as the seabed conditions in which they were to be bur-