Kentish Flats extension update

Kentish Flats is one of the earliest UK Round 1 windfarms and while of modest proportions compared to recent developments, when commissioned in 2005 it was a notable project at the start of the UK offshore wind programme. Thirty Vestas V90-3.0MW turbines with a total capacity of 90MW export energy directly to the grid around 9km away via cables with no sub-station.

In May 2010 Vattenfall was given the opportunity to extend the windfarm by The Crown Estate, part of the so-called Round 2.5 programme. The extension of a number of projects was intended to bridge the gap and maintain momentum as the earlier Rounds 1 and 2 windfarms were completed and industry geared up for forthcoming and substantially larger Round 3 projects.

Following discussions, and consultation with various stakeholders, Vattenfall sought consent from the Planning Inspectorate and in February 2013 consent was granted for an additional 17 turbines bordering the southern and western sides of the existing site. Total additional installed capacity will be up to 51MW.

As is the norm with such projects much preparation including planning and engagement with supply chain elements has taken place behind the scenes and the second half of 2014 has seen actual work getting underway.

Preparatory work has now commenced along the route of both the infield and export cables. On behalf of Vattenfall, Bohlen & Doyen GmbH have commenced jetting and trenching operations including laying of concrete protection mattresses over cable crossings to protect the existing Kentish Flats and London Array windfarm cables.

The cable lay barge Bodo Installer is carrying out this work assisted by two tugs from the fleet of Herman Sr BV: the Damen Shoalbuster 2308 Baloe and the larger, more powerful Damen Shoalbuster 2509 Bommel. Work is also underway onshore where the cables will be connected to the existing grid: actual offshore cable installation work is due to begin in May 2015.

Five existing Round 1 and 2 windfarms were awarded extension rights in 2010: Greater Gabbard (Galloper), Thanet, Kentish Flats, Burbo Bank and Walney. Operators of the first two subsequently decided not to proceed with the projects but the other three are on track with Walney Extension and Burbo Bank Extension recently receiving Development Consent Orders from DECC. The Walney extension will see up to an additional 660MW of capacity, DONG Energy stating turbines between 6MW and8MW will be utilised. Burbo Bank Extension will see an additional 250MW capacity added and earlier in 2014 DONG Energy announced a conditional agreement with MHI Vestas for the purchase of 32, V164-8.0MW turbines.

By Peter Barker