FAILED: Offshore Wind Turbine Foundations, Blades and Cables
If Cape Wind was constructed as 130 Siemens 3.6 MW turbines, it would have failed.
Offshore wind blades, monopole foundations, and cables have failed featuring Cape Wind specifications,
(130) Siemens 3.6MW wind turbines.
The US has adopted the European monopole standard foundation design code (J101). Borrowing from oil and gas industries technology, they failed to incorporate wave and other critical load factors!
OFFSHORE WIND MONOPOLE FOUNDATION FAILURE
The U.K. Supreme Court has made a landmark ruling, 7/17, that the fundamental offshore wind turbine design code has failed, industry-wide. The U.S. has adopted the U.K. offshore wind design code (J101).
Industry Tech source explains in detail what went wrong with offshore wind monopoles historically “sinking”, “shifting” and “corroding”-
‘Offshore Wind Foundations: Research Needs And Innovation Opportunities - Wind Systems Magazine’
“The need for design refinements can be traced back to the fundamental goal of design standards, which is to ensure that resistance is larger than the applied loads. The offshore wind industry, however, whose towers differ substantially from oil platforms in terms of loads and resistance, has adopted foundation design protocols of oil and gas installations but has selectively addressed only some of the characteristic differences of the two industries, and what’s more, has done so independently of each other. This has led to offshore wind foundation standards that lack an overall design philosophy, and have large built-in uncertainties in the characterization of loads and resistance — wind speed, wave height, wave kinematics and slam forces, steel and soil stiffness and strength, and soil-foundation interaction — uncertainties that are, in fact, disproportionately larger than the narrow window of performance requirements of offshore wind installations...”
Hence-‘Dramatic Technology Shifts are Expected for Offshore Wind Technology’:
One of the principal disadvantages of rapid and inorganic technological deployment, such as that required by the European Union’s renewable energy targets, is that problems are very widespread by the time they are discovered. The prudent approach is to stay behind the learning curve, so that the consequences of type failure affect only a small number of installations. Dashing ahead of the learning curve is asking for big trouble.
Recent weeks have seen several reports that Ørsted, as DONG Energy is now called, is faced with the distressed repair of over six hundred offshore wind turbines supplied by Siemens. Five hundred of these are in British waters, and somewhat over one hundred are offshore Denmark, with a further 80 in German waters.
West of Duddon Sands, a joint venture between Ørsted and ScottishPower, is an offshore wind farm of 108 Siemens 3.6 MW turbines (SWT 3.6 MW) with a total capacity of 388.8 MW. It was officially opened by the then Secretary of State for Energy and Climate Change, Ed Davy, and began generating in February 2014.
It now appears that all 108 wind turbines have erosion problems on the leading edges of their blades, requiring removal and reconditioning. Renewable Energy News(renews, issue 377, available only to subscribers), is reporting that this will entail the application of a rubber covering, a process that will take three to ten days per turbine. Work is expected to start later this year and will stretch into 2019.
Renewable Energy News added that this problem was also present at Ørsted’s Walney 2 offshore windfarm, a site comprising 51 Siemens 3.6 MW turbines with a capacity of 183.6 MW.
In total, Renewable Energy News stated that the problem was found in 500 UK offshore wind turbines, and was probably also found in at least one, unnamed, German offshore wind farm, affecting some 80 turbines.
The Danish newspaper Jyllands Posten (Danish report here: and translated here) and RE News online are now both reporting that the problem also affects the Danish Anholt offshore wind farm, a site comprising 111 Siemens 3.6 MW turbines,with a total capacity of 400 MW. Some 27 of the wind turbines were repaired last year, 2017, and the remaining 84 are scheduled for repair in the coming year.
The Siemens 3.6 MW turbine which appears in all these instances entered the market in 2010, and there are, according to RE News, some 950 in European waters.
The cost of the repairs will almost certainly be very large. Assuming a repair vessel charter rate of about £150,000 per day, and, say, five days per turbine, this amounts £750,000 per turbine, plus additional labour and equipment costs. In total the cost seems unlikely to be less than £1m per turbine, which equivalent to between 5% and 10% of the total project cost. Even if it is only half that sum, this is a very expensive repair very soon after commissioning, to say nothing of the lost generation and income during the repairs.
It is not yet clear who is to pay for this work.
Cut and continuing-
But if the need for these repairs is, as Siemens is apparently contending, just every day wear and tear, then this sort of problem is unlikely to be confined to the SWT 3.6 MW device, and will be strong evidence confirming long-held suspicions that developers and owners have greatly underestimated the normal cost of wind farm Operation and Maintenance (O&M).
Read full article, here:
Insurance industry source for insured offshore Wind corrosion issues-
Summary: Offshore wind turbines are corroding internally & externally & industry is challenged to correct ongoing problems.
[Offshore Wind] ‘Industry must face up to growing cable failures’
“Operational failures now make up about 80% in value of all cable-related claims, a delegate from the insurance industry claimed...”
“Cable failures are one of the main risks affecting offshore wind operations
Cable failures are one of the main risks affecting offshore wind operations because they can shut down an (important part of an) offshore wind farm for a duration of months, resulting in a financial as well as a societal impact. Despite the fact that power cables typically form only 5 to 10% of the total investment costs in an offshore windfarm, they account by far for most of the unavailability of the windfarms, and for claim costs of 100s of millions of Euros annually. In view of the development of the number of offshore wind farms, this amount will increase considerably in the future. Cable inspections and repairs are expensive maritime operations. Repairs on cables can easily take weeks or even months because of the weather or the limited available of equipment and vessels. That can severely impair revenue and also reduce the technical lifetime of offshore wind farms...”
Cable installation and repair cost-
Cable problems, (more than 70% of wind project insurance claims), repair average cost is U.S. $6,450,630.08.
( conversion € 5 million).
Subsea Cable INSTALLATION cost averages $6 million per mile per Sue Tierney Analysis Group