The massive London Array project in the Thames Estuary, in Kent, South East England, has reached another milestone with its new type of wind turbine foundation design being given the seal of approval by industry certification experts DNV.
Animation of London Array Offshore Windfarm can be seen here:
London Array is among the first in the world to use a conical joint at the top of its monopiles to prevent transition piece slippage. The design was undertaken in parallel with a separate joint industry project established to overcome problems that have been reported on some monopile foundations.
DNV has now formally approved the new design and also issued statements of compliance to cover the rest of the turbine and offshore substation design.
London Array Project Manager, Soren Thorbjorn Larsen said, “The construction and design of what will be the world’s largest offshore wind farm is a major technical and engineering challenge, and we have paid close attention from the very beginning to ensure that we got the design absolutely right. As well as dealing with new industry issues, such as how to safeguard against foundation grouting and slippage problems, we have had to take into account the wide variation in water depths and moveable seabed across the wind farm site. I was delighted to receive formal certification and expert recognition that London Array meets the highest industry standards.”
The new foundation design features a gently sloping cone at the top of the monopile which then sits inside an inverted cone at the bottom of the transition piece. A layer of grout lies between the two surfaces. This may become the new best practice for offshore wind construction.
The London Array project was born in the year 2001 when a series of environmental studies in the outer Thames Estuary confirmed the area is a suitable wind farm site. Two years later, the Crown Estate gave London Array Ltd a 50-year long lease for the site and a cable route to shore.
Planning consent for a 1GW offshore wind farm was granted in 2006, and permission was granted for the onshore works in 2007. Work on the 630MW, 17-turbine first phase One, started in July 2009 and will be completed in 2012. At 1,000MW, the project is currently the world’s largest consented wind farm.
It is being developed by a consortium of Dong Energy, Eon and Masdar in the following per centages:
The key stats for the Project are
- An offshore area of 100km2
- 175 wind turbines
- Two offshore substations
- Nearly 450km of offshore cabling
- One onshore substation
- 630MW of electricity
- Enough power for around 480,000 homes a year – two thirds of the homes in Kent
- CO2 savings of 925,000 tonnes a year