International Dredging Review

International Dredging Review

Tideway BV a subsidiary of the dredging environmental and marine engineering group DEME headquartered in Zwijndrecht Belgium has announced that it has been awarded a design-and-build cable installation contract by DONG Energy for the offshore wind farm Hornsea Project One. This is the first of three proposed sections of the Hornsea wind farm located in the North Sea off the southeast coast of England in the vicinity of Hull. DONG Energy is a leading energy group in Northern Europe headquartered in Denmark. 

Tideway will deploy DEME’s newest Class 3 Dynamic Positioning (DP3) vessel Living Stone for the project a highly advanced subsea cable-laying vessel. She is currently being built by the Spanish shipyard LaNaval located near the city of Bilbao Spain. LaNaval Shipyard specializes in building suction dredges as well as vessels for the offshore oil and gas and offshore wind energy sectors. The Living Stone has an innovative modular cable/umbilical handling as well as a 10000 ton cable capacity divided over two turntables arranged below deck. In addition the vessel is equipped with dual fuel engines where LNG is the primary fuel. Delivery is scheduled for April 2017. 

The scope of work for Tideway at Hornsea involves cable-laying pre-trenching backfilling pre-sweeping route preparation and rock placement of three high voltage subsea power cables from the shore to three different offshore substation platforms as well as the installation of two interlink cables. 

As the project is being built 120 kilometers (75 miles) out at sea these three subsea power cables will be extremely long – 134 kilometers (83.5 miles) 140 kilometers (87.5 miles) and 152 kilometers (95 miles). This will also require a reactive compensation platform to be installed between the three substations and the shore. The interlink cables will be 13 and 14 kilometers (8.1 and 8.75 miles). The power cables will be pulled ashore near Horseshoe Point immediately south of the Humber Estuary on the Yorkshire coast.

Execution of the offshore project will begin in 2017 with the engineering route survey after which work will continue for two years. The last export cable is scheduled to be laid and protected in mid-2019. The Hornsea Project One offshore wind farm will be capable of powering more than one million homes along the Yorkshire Coast of the United Kingdom. Covering approximately 407 square kilometers (157 square miles) and providing a capacity of 1.2 gigawatts (GW) Hornsea Project One is expected to be operational in 2020. It will be the first offshore wind farm to exceed 1 GW in capacity and will become the world’s largest offshore wind farm. A scoping report for Hornsea Project Two was is-sued in 2012 and consultation on Hornsea Project Three was undertaken in May 2016.