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Offshore Wind Presents Powerful Opportunities, Gusty Challenges
3sun Group Offers Installation, Maintenance for Wind Turbines at Sea


Andrew Elmes

3sun Group wind turbine installation at Gwent y Môr wind farm.
As an alternative to fossil fuels, wind power is plentiful, renewable, clean and produces no greenhouse gas emissions during operation. The effects on the environment are generally less problematic than those from other power sources. In 2010, wind energy production was more than 2.5 percent of total worldwide electricity usage, and growing rapidly at more than 25 percent per annum. At the end of 2012 there were more than 225,000 wind turbines operating across 80 countries.

As technology progresses, turbines are becoming bigger and more efficient, with the same amount of energy generated from fewer machines. Offshore wind is less turbulent and stronger than on land, and offshore wind farms have less visual, noise and shadow flicker impact, but construction and maintenance costs are considerably higher.

3sun Group, based in Great Yarmouth, England, realizes the potential of the offshore wind turbine industry as part of its service offering to the energy sector. The Group's team of highly skilled engineers and technicians work with the leading energy operators and original equipment manufacturers (OEMs) to address the challenges that affect the offshore wind sector. The Group has experienced significant business growth since it was established in 2007, growing from one person to now employing more than 300 people, including more than 160 wind turbine technicians on and offshore. It is on track to deliver revenue in excess of £30 million this year.

Partnering With Siemens
Despite its roots in oil and gas, 3sun Group has been involved in the offshore wind industry since its infancy. Through acquisition of its subsidiary company Dawson Energy, the U.K.'s only home-grown wind turbine installation company, the firm cemented close relations with Siemens (Munich, Germany) in the onshore wind market. When Siemens established itself as the market leader in offshore turbine supply, the Group moved with it to provide key installation and service expertise, which has seen it work on construction of projects like Burbo Bank, Liverpool Bay, Greater Gabbard off the Suffolk coast and more recently the London Array, the world's largest offshore wind farm with 175 turbines, each rated at 3.6 megawatts, spread over an area of 90 square kilometers. The SWT-3.6-107 wind turbine is one of the largest models in the Siemens Wind Power product portfolio and specifically designed for offshore applications. The London Array has a total capacity of 630 megawatts and supplies the U.K.'s national grid with enough electricity to power half a million homes.

Following the successful installation of hundreds of its 3.6-megawatt turbines, the Group expects to support Siemens to build the first commercial 6.0-megawatt farm this summer at Westermost Rough. Located off the East England coast, the wind farm will be constructed of 35 turbines for a 210-megawatt capacity, providing carbon dioxide-free electricity for around 200,000 homes. Siemens installed a test turbine in West Kilbride, Scotland, in preparation for the commercial deployment of the new model. The turbine has a 154-meter rotor, designed specifically for the Siemens 6.0-megawatt machine. It has a swept area of 18,600 square meters and is currently the world's longest blade in operation. It maximizes energy yield at offshore locations, from inland waters with moderate wind resources to the most exposed offshore sites.

Cost Challenge
One of the biggest challenges faced by the fledgling industry is that offshore wind has one of the highest costs of any energy-generating technology currently available. As outlined in the Offshore Wind Cost Reduction Task Force report, published in July 2011, the U.K. government made it clear that the cost of electricity from offshore wind would have to fall significantly to meet the objectives of 18 gigawatts of capacity, with the target cost of £100 per megawatt-hour of energy by 2020.

Increasing the size of offshore turbines is key to driving down this levelized cost of energy (LCOE) and to make offshore wind commercially viable. This manifests in a rush for manufacturers to launch ever larger turbines, resulting in often incomplete or untested configurations that have to be proven or retrofitted on site. The response of the supply chain is key to provide the logistic and engineering support to allow this development. This is most apparent in installation vessels, with the fleets struggling to keep up with the requirement for ever larger jack-up vessels and crane capabilities to cope with the design aspiration of the next-generation turbines. In accommodating the storage and installation of the new models with existing fleets, operator skill is key to load the vessels, plan the lifting operations and manage the construction, often at the edge of crane limits and vessel dimensions. 3sun Group has been fortunate to develop and retain some of the most experienced construction managers in the industry, and even they are tested daily with the demands of the project builds.

3sun Group has established itself as a consultancy for other less experienced companies in this sector. Areva (Paris, France) is installing two projects off the German coast with its 5-megawatt turbine, and 3sun Group has been able to support its rapid education into the requirements of offshore installation by providing its most experienced construction managers to coordinate the installation work, acting as client representatives and quality advisers to assure the standard of the completed installation.

This year, 3sun Group will support Vestas's (Aarhus, Denmark) return to the offshore wind market with its installation of the 73-turbine Humber Gateway wind farm off the coast of East Riding in Yorkshire. The team will be responsible for the electrical and mechanical completion of its 3-megawatt machines, an expertise for which Dawson Energy has been renowned for the past 14 years.

3sun Group has also completed work on the operational Greater Gabbard wind farm, where its engineers identified failings in the design of a transitional piece for loading a vessel. 3sun Group engineers implemented an A-frame design for the transitional piece, which meant that production did not need to be stopped during the installation.

The team also identified other modifications to the Greater Gabbard site, which included maintenance on jacket points and welding. Its proactive approach reduced time and associated costs of service and inspection of the turbine to maintain statutory compliance; all aspects, which in their own small way, reduce the LCOE of offshore wind. To continue this article please click here.

Andrew Elmes joined 3sun Group as renewables director in November 2013, with 20 years of energy and project management experience. After an initial career as an engineering officer in the British Army, Elmes established the U.K. project organization for Siemens Energy Renewables. He recently worked as a bid management consultant with an Australian infrastructure company and completed an MBA. br />

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