When the construction team moves on

London Array is a joint venture set up to build and run the 630MW offshore project. General manager Mike O'Hare reflects on the challenges faced as the project, fully operational since April, moved from construction to operations and taking advantage of each partner's experience.

The 630MW London Array is the world's biggest operating wind farm (pic:Siemens)

Offshore wind is a developing technology and nobody has all the answers - or even knows all the questions. Every project presents its own, unique challenges. In an ideal world, there would be a standard design for your offshore wind project and you would just have to find a suitable site. That is not how it happens in practice.

London Array, a joint venture between utilities Dong Energy (50%) and E.on (30%) and Abu Dhabi-based clean-tech investor Masdar (20%), has from the start brought in people from a broad range of backgrounds and encouraged them to adopt new ways of working.

We have benefited from a long handover period. When I took on the management of operations and maintenance (O&M) in August 2011, only the two offshore substations and a handful of foundations for the turbines had been installed. The O&M base itself was still a building site.

The first turbines started generating power in October 2012, and the formal handover of the first batch from the construction team to the operations team took place in January 2013. Work on the electrical assets - burial of the array cables, for example — has been completed and, at the time of writing, we are waiting for responsibility for them to be handed over to us.

Construction check

This phased handover has worked well for us, especially given the complexities that can come from being a joint venture. If we were part of a major utility and encountered problems with elements of the construction, we could call on whoever we needed from the original construction team to deal with it.

In our stand-alone joint venture, however, once the construction team has gone, it has gone, so we need to be certain that any teething problems or unexpected issues have been dealt with before they go.

We have put a great deal of energy into making sure things have gone well for stakeholders, shareholders and the local community alike. There has been good co-operation between the construction and operations teams — for example, we have maintained the excellent health and safety record from the construction phase. And we delivered the project on time and on budget.

We invested in the best and latest technology but, while looking to improve availability and reliability of the project's 175 turbines, we were prepared to acknowledge that, since signing off our original specification for the turbines with Siemens in May 2009, new developments had come along that would improve performance. Siemens worked with us in an open and honest relationship, to help meet our expectations.

For example, since our turbines were originally developed, improvements in blade aerodynamics have been achieved. With Siemens, we have responded, and the blades at the site have recently been given a post-construction upgrade to incorporate the latest aerodynamic abilities, and we are now achieving better energy output from the same infrastructure.

That open relationship extends to our shareholders. From the outset, Dong Energy, E.on and Masdar have seconded some of their best people to the project. Masdar supplied the interface engineer on the onshore and offshore substation, and the project drew heavily on the company's expertise in cost and risk management. Dong Energy provided the project and construction managers, while the commercial and operations manager came from E.on. The current three-strong operations management team comprises one representative from each company, offering a wider pool of people to drawn on and offers peace of mind to the different parties in the joint venture.

London Array continues to make use of the expertise from the shareholders. E.on, contracted to provide trading and accreditation services, acts as our interface with grid operator National Grid and deals with renewable-energy policies that apply to us, such as our renewable obligation certificate (ROC) and levy exemption certificate (LEC) accreditations.

Dong Energy handles the day-to-day running of the wind farm, including managing the contractors on site, marine co-ordination and health and safety. It currently has 27 technicians and six apprentices working on the project, with Siemens providing 35 turbine technicians.

Managing change

How people work together, corporately and individually, is crucial to creating a successful joint venture. All three parties at London Array knew from the outset that several elements during the build process could change dramatically over a period of time. In our experience, by negotiating in a professional and respectful way with the other partners, solutions can be found with a minimum of fuss.

There was a great deal of often-complicated work to be carried out to ensure the governance process was correct. With the next generation of offshore wind farms, many of which are also joint ventures, the increase in scale adds another layer of complexity. The companies involved may be able to learn from our experiences in governance, corporate functions, construction and the transition to operations. All parties need to accept that circumstances change as the project develops, and that gaps may appear in the original governance and contracts through unexpected developments.

Shell was a key shareholder in the London Array joint venture at the set-up. The oil company exited the project in 2008, selling its holding to Dong Energy and E.on, but it had played a key part in some of the early policies that established joint-venture working, such as creating the project "quilt", which describes the work split within the project packages.

Expect the unexpected

We have learned to expect the unexpected. From a risk-management point of view, you need to accept that things will happen and to build that into your thinking. A typical example, although not one that caused too much trouble, was a crew transfer vessel taking technicians to two turbines, 650 metres apart. The vessel had to make a round trip of 14 kilometres to get from one to another because the sand banks had shifted.

On the subject of boats, the offshore wind industry has plenty of work still to do in terms of design and technology to find the right balance between efficiency, comfort, manoeuvrability, speed and safety.

We are operating in relatively shallow water and use a mix of propellor and jet-propelled craft. The former has more thrust in rough seas, but the latter is more manoeuvrable. The combination works for us, but we are in discussion with our suppliers to see how we can improve on that mix in the future. The third round of UK offshore wind farms will be built in deeper waters and careful thought will have to be given to procuring the right equipment.

Local resources

Wherever possible, we have looked to source local suppliers for the O&M contracts. IT support plus accounting, legal and HR services have all gone to local companies in Kent.

Thinking local also holds true for staff. You need to make sure you have the right people, well-trained and with the right tools, but it is equally important to encourage and listen to their feedback. Your technicians are at the sharp end. They are learning valuable lessons about how to service the turbines and that knowledge must be shared.

This is a growing industry that needs new people, and London Array has supported nine apprentices brought on and trained by Dong Energy. We are lucky in that Kent has a good base of both skilled technicians and people who can be trained and skilled in the future.

Although we will always need to make use of expertise from outside the area, it is good for us to help build an indigenous skills base. We will be here for 25 years, so we should get the best for us and the best for the local area.

Attitude is as important as expertise, when employing staff. As a young and evolving industry, we need a willingness to learn and be proactive. You also need people with the right negotiating and relationship management skills.

We have increased the number of technicians from an expected 50 to 70 working on the project. While this creates a vibrant and dynamic workforce, it has meant that we need to use the construction offices to cope with the extra people on site. My advice to future developers would be to anticipate how the operations strategy may change over its life and to incorporate flexibility when planning office space.

Time is another key factor in a successful handover to O&M — consider what needs to be done and how best to do it, as well as time for people to carry out the handover effectively.


Lessons too, can come from elsewhere, such as the automotive industry. Can we do anything to standardise turbine production and the construction of the wind farms, for example? At London Array, every foundation is unique in its design, every array cable has been cut and installed individually.

Could that be more standardised? All cars that come off the production line look the same, but they will be built to different specifications. There is standardisation, but also tweaking: some will have certain extras, others will not. Can we do that in the offshore wind industry and learn how to keep things simple?

Mike O'Hare is general manager at London Array



London Array was born in 2001, when environmental studies confirm the outer Thames Estuary is a suitable site for a wind farm.


London Array became the first Round 2 offshore wind farm to apply for construction consent in June 2005. Consent for the offshore works was granted in December 2006, onshore consent followed in August 2007.


Suppliers for the offshore elements were appointed following tender process. Onshore substation designs approved. Local network diverted slightly to enable substation connection.


Phase one of the project received formal approval and the three shareholders announced they would jointly invest EUR2.2 billion in building the initial 630MW phase. Most pre-construction surveys for onshore substation completed by spring. Construction on the Cleve Hill onshore substation started in July, access road for substation completed in December.

Summer 2010

Offshore construction base built at Ramsgate port. Onshore substation control room construction completed. Transformers for onshore substation delivered. Internal concrete roads and pavings for substation completed.

October/November 2010

Offshore construction team mobilises at Ramsgate. Phase-one civil construction works for substation completed. Start of electrical and mechanical installation at substation.

March 2011

Start of foundation installation. Start of phase-two civil works for onshore substation.

July/August 2011

Offshore substations installed and start of array cable installation.

Autumn/winter 2011

Substation commissioning.

Installation of first export cable.

January 2012

Start of turbine installation — 175 turbines to be installed in all.

September 2012

Installation of the final export cable.

October 2012

Construction of onshore substation completed. First power generated.

December 2012

Major construction complete with installation of final turbine.

January 2013

Transfer to operations and maintenance team begins.