When construction began in 2009, London Array was conceived to be the world's largest offshore wind farm — and building it meant repeating a monopile installation sequence 175 times across the outer Thames Estuary, then lifting two complete offshore substations into place using one of the industry's specialist floating cranes.
Scale, not novelty, was the engineering problem. Every element of the installation — foundations, turbines, substations, cabling — had to work at a volume no offshore wind project had attempted before.
Not one difficult foundation — one hundred and seventy-five ordinary ones, repeated at a scale no offshore wind project had attempted before.
London Array produced first power in October 2012, and the 175th and final turbine was installed that December. The project stands as a reference case for offshore wind installation at volume: the engineering challenge wasn't inventing new methods, but proving that monopile foundation installation, marine turbine erection, and floating-crane substation lifts could all be repeated reliably across an entire wind farm the size of a small city.
For further reading on offshore wind foundation methods, see What is Heavy Lift Engineering?
Related case studies: Horns Rev 1 · Hywind Tampen · Dogger Bank
Sources: London Array Limited — project owner's technical description; IET Engineering & Technology Reference — peer-reviewed account of the foundation and substation installation; Institution of Civil Engineers; Engineering News-Record. London Array was the largest offshore wind farm by capacity at its 2013 commissioning; it was surpassed by Walney Extension in 2018.
Frequently Asked Questions
London Array Phase I comprises 175 Siemens 3.6 MW turbines with a combined capacity of 630 MW, and was conceived as the world's largest offshore wind farm when construction began in 2009.
Monopile foundations were supplied by a joint venture between Per Aarsleff and Bilfinger Berger, with a consortium of MPI and A2SEA providing marine crew and vessels — including the purpose-built installation vessel MPI Adventure — for the offshore installation of foundations and turbines.
The two offshore substations were designed, built, and installed by Future Energy, a joint venture between Fabricom, Lemants, and Geosea. Each substation was assembled onshore, transported to site by boat, and lifted into place using the Rambiz, a specialist floating crane.
Offshore construction began in March 2011 with the first of 177 foundations. The wind farm produced first power in October 2012, and the 175th and final turbine was installed in December 2012.