The offshore wind industry is developing at an impressive rate of knots, particularly in Northern Europe, where high levels of investment continue to abound.
The two principal markets remain Germany and the UK. Earlier in the year, the former’s government announced its plans to increase its offshore wind power capacity to 6.5GW by 2020. Despite the original target having been 10GW (before it was revised in January) such a declaration is hardly to be scoffed at.
Across the Channel, the goal – for the same time period – is 18GW. At present, 3,000 turbines are in operation or under construction, as part of Whitehall’s pledge to use more of the UK’s renewable energy resources.
Notable projects include the likes of Gwynt y Môr, situated off the North Wales coast. Upon its completion – forecast for early 2015 – it will become the world’s second largest wind farm, with a capacity of 576MW.
Industrial practices
London Array will, however, still hold the top spot as the world’s largest offshore wind power plant. Inaugurated in 2013, the facility, which sits 20km off the Kent coast in the outer Thames estuary, consists of 175 turbines and 630MW of installed capacity. That’s enough electricity to light up 500,000 British homes.
Despite its impressive growth, however, the industry is still on a learning curve. The construction of wind turbines off dry land can be, somewhat understandably, demanding when it comes to transport and logistics. A project of London Array’s magnitude can be viewed as an experiential benchmark by which wind companies can better understand and meet the technical challenges of successfully delivering an offshore facility.
Turbine manufacturers are increasingly looking at industrial models to reduce their operational costs and become more time efficient in order to compete with conventional power sectors.
There has also been a palpable shift towards standardising construction processes in the wake of London Array, which was completed at a faster rate than any preceding offshore farm. The time taken from the installation of the first monopile foundation in March 2011, to the activation of the final turbine in April 2013, edged just past the two-year mark.
During the course of the project, Siemens Wind Power, which supplied the turbines and grid power, made a concerted effort to streamline all its offshore installation processes – from manufacturing to transport and logistics – through the industrialisation and optimisation of the preassembly and commissioning works.
Having already installed more than 1,100 turbines at sea, Siemens is a market frontrunner for the supply of offshore wind power plants and grid connections. It also has 4.6GW’s worth of offshore capacity projected for the future, including Gwynt y Môr.
Standardising processes is key, says James Oxbrow, project manager at Siemens. During the group’s involvement in London Array, all work – where possible – was reassigned further up the production line to create better and safer working conditions for technicians.
Standard procedure
"Standardisation has the ability to improve efficiency in everything we do," he explains. "We want to ensure that we minimise the amount of work we are doing offshore at all times so we are always looking to push work back up the chain into our preassembly ports, and even further back into the factories."
In fact, costs are estimated to be ten times higher when working offshore, in contrast to the production facilities referred to by Oxbrow. Work that could take two technicians two days to complete offshore can instead be done in a "clean, warm factory in a couple of hours", creating a reduction in fault identification.
For example, precommissioning testing on tricky tasks, such as enclosing the entire electrical system inside a nacelle, can be conducted on the quayside, reducing the need to venture onto water.
"You could call it a holistic approach," he says. "The idea of reducing our time on the water was a key focus of London Array from the moment we received a detailed study of the project. It is now a key area for Siemens, globally, as a whole, as it looks to develop its products."
The challenges associated with building an offshore wind-farm are self-evident and London Array was no exception. In addition to its distance from shore, high winds and inclement sea conditions, especially during winter, made transporting components from the quayside to the site a taxing undertaking.
"The biggest challenge was trying to get to grips with the weather, and planning around it," says Oxbrow. "Huge variations in wind speeds and the sea state were experienced throughout the construction, which affected how many turbines could be installed in a given week."
Every process, from the manufacture of components, to the testing of installed turbines, was consequently isolated and analysed in order to identify areas in which cost and time savings might be made.
Siemens’ project team even compiled a 170-page document detailing explicit requirements of when a respective component could be judged to be truly finished.
London Array’s customers were also involved in the creation of these standards to ensure that each of the turbines produced was of the desired quality. By recording completion standards and expected timeframes for each of these processes, Siemens was able to better judge its performance, in terms of quality and time.
The deployment of this form of offshore marine coordination also allowed the group to successfully minimise vessel journeys and offset a potential backlog of components.
"We constantly had to make sure that we had a buffer of components on the quayside, ready to be loaded onto vessels and taken to the site," explains Oxbrow. "It was quite a logistical challenge, because the backlog of components can not only cause downtime, but jam up the entire supply chain. It was essential we got that buffer right."
Tracking changes
Technology also played a vital part. Siemens made use of Primavera software – commonly deployed in offshore wind projects – in order to have greater track-and-trace visibility across the supply chain.
"We had a very detailed Primavera plan and programme, which effectively detailed the value chain from the manufacture of all major components to when they were commissionedand handed over to the customer," says Oxbrow.
"So, if we saw any delay in the delivery of a particular component, we were able to track it, as well as its potential impact. It was one of the main tools we used, which together with information collated from the site through daily progress reports, allowed us to have excellent visibility."
The London Array project has provided a perfect proving ground for both the industrialisation and standardisation of offshore wind projects. But if the offshore industry is to truly take off on a global scale, such progress cannot afford to decelerate.
It is fair to predict that the developing marine wind farms will become even tougher in the future, whether that concerns building in deeper waters, or the requirement of larger and heavier components. To mount such logistical hurdles, a commitment to ramping up efficiency, while driving down costs, is paramount. We should expect players, such as Siemens, to continue to adjust their offshore solutions accordingly.
