IEA R&D WIND TASK XI
The Operating Agent
May 20th 2010
To: Members of the Executive Committee, IEA R&D Wind, Task XI
Topical Expert Meeting #63
on
HIGH RELIABILITY SOLUTIONS AND INNOVATIVE CONCEPTS FOR OFFSHORE WIND
TURBINES
Dear Colleague,
At the Executive Committee meeting #64 (Huatulco, Mexico) it was decided to arrange the 63rd
Topical Expert Meeting on “High reliability solutions and innovative concepts for offshore wind
turbines”. Venue and date for the meeting is as follows:
SINTEF Energy Research, Trondheim, Norway
on
September 21-22 2010
The meeting will begin at 09:15 am on Tuesday and end on Wednesday at 14:00 hours followed
by an optional tour. Please forward an invitation to 2-4 people from your country that will be
able to discuss the subject in detail.
In order to give meeting background and aim, an Introductory Note is attached to this letter.
Participants in the meeting are requested to give a short and informal presentation of results from
ongoing research/experiences and future plans. Proceedings from the meeting will be distributed
soon after the symposium. To assist in this, the participants are urged to bring along one copy of
the material they want to have included in the documentation; preferably in digital format.
Details on travel and accommodation can be found below. Local host is SINTEF Energy
Research represented by senior research scientist John Olav Tande. Questions regarding content
and the agenda will be answered by myself on +34 91 417 50 42 / 638 095909 or e-mail
favia@cener.com. Please inform me and Randi Aukan (secretary), randi.h.aukan@sintef.no, of
the participants you would like to send to the symposium. An Acrobat Reader version of this
invitation can be found on the Internet:
http://www.ieawind.org/Task_11/Task_11_HomePage.html
An optional tour to the Ocean Basin Laboratory at MARINTEK is planned on Wednesday 22
September 14:00 – 16:00 hours.
Best regards
Felix Avia Aranda
Task 11 Operating Agent
Attachments:
1. IEA Background and Meeting Format
2. Practical arrangements
3. Introductory Note
IEA Background and Meeting Format
The objective of IEA R&D Wind Task 11 is to promote wind turbine technology through cooperative activities and information exchange on R&D topics of common interest. One way to
achieve this is to gather experts in Topical Expert Meetings (TEM).
More information can be obtained from:
IEA general
IEA official home page
IEA RD&D Wind general
http://www.iea.org/
http://www.ieawind.org/
Task 11
General information
http://www.ieawind.org/summary_page_xi.html
Meeting format
The meetings are of the workshop type, where information is presented and discussed in an open
manner. The participants decide by themselves what they would like to present. Guidance for
presentations is given in the Introductory Note that is distributed together with the invitation to
the meeting. This implies that there is no list of presentations in advance.
The meetings will cover two days, starting 09:15 at day one and ending at 14:00 on day two.
Oral presentation is expected from all participants. The allocated time is 15-25 minutes including
questions and discussion. However, the time is dependent on the number of presentations.
The agenda usually covers the following items:
1.
2.
3.
4.
5.
6.
7.
Introduction, host
Introduction by Operating Agent, Recognition of Participants
Collecting proposals for presentations
Presentation of Introductory Note
Individual presentations
Discussion
Summary of meeting
Documentation
Proceedings from the meeting will be prepared soon after the symposium. To assist in this the
participants are urged to bring along one copy (preferably in digital format) of the material they
want to have included in the documentation. A summary of the meeting will be written by the
host or persons involved in preparing the Introductory Note.
Miscellaneous
For presentation purposes a computer and beamer will be available. Please bring your
presentation on a memory stock or CD.
Practical arrangements
Date and venue
Location:
SINTEF Energy Research, Sem Sælandsvei 11, NO-7465 Trondheim, Norway
Date and time: Start 2010 September 21 at 9.15; end September 22 at 14.00
Optional tour: September 22 (14.00-16.00) to Ocean Basin Laboratory
Hotel accommodation
Radisson Blu Royal Garden Hotel, Kjøpmannsgaten 73, Trondheim offers accommodation to a
price of NOK 1150 per night incl. breakfast. Please book directly to the hotel referring to
106471/1009Sintef
Phone: +47 73 80 30 00, Fax: +47 73 80 32 50
http://www.radissonblu.com
Please note: A block reservation of 20 single rooms has been made for 20-22 September. These
are kept until 20th August.
1 EUR ~ 8 NOK.
Travel Instructions
Flight
Closest airport is Trondheim Airport Værnes located 35 km north of the centre of Trondheim.
More information about the airport and flight connections can be found on
http://www.avinor.no/en/airport/trondheim
Getting between the airport and Trondheim
The airport busses departure from Værnes to Trondheim city centre four times every hour on
weekdays, day and evening. The bus stops at Radisson Blu Royal Garden Hotel. Travel time is
about 40 minutes. Cost about 100 NOK. See http://www.flybussen.no/trondheim/
Taxi takes around 25 minutes and costs about 500 NOK.
Getting between hotel and SINTEF
The distance between the hotel (Royal Garden) and SINTEF is about 3 km, and takes about 35
minutes on foot. A taxi takes about 15 minutes and cost about 150 NOK. See map for locations.
Map of Trondheim: A is Radisson Blu Royal Garden Hotel, Kjøpmannsgaten 73. B is SINTEF
Energy Research, Sem Sælandsvei 11.
Optional tour
A tour to the Ocean Basin Laboratory is scheduled on Wednesday September 22, 14:00 – 16:00.
The Ocean Basin Laboratory is used for studying basic as well as applied ship and offshore
problems. A total environmental simulation including wind, waves and current offers unique
testing conditions for scaled models of all types of fixed and floating structures, hereunder
offshore wind turbines.
http://www.sintef.no/Home/Marine/MARINTEK/Laboratories-at-MARINTEK/The-OceanBasin-Laboratory/
Please indicate your interest to Randi Aukan (secretary), randi.h.aukan@sintef.no before 10th
September.
INTRODUCTORY NOTE
IEA Topical Expert Meeting #63
on
HIGH RELIABILITY SOLUTIONS AND INNOVATIVE CONCEPTS FOR
OFFSHORE WIND TURBINES
John Olav Tande
Background
Targets are set for a massive installation of offshore wind farms. In Europe alone plans suggest
40 GW by 2020 and 150 GW by 2030 as viable. The development is ongoing, but in an early
stage. Only about 2 GW of offshore wind farms have so far been installed, and all relatively
close to shore at shallow waters using what can be called on-shore wind technology. The
exceptions are the Beatrice wind farm installed at 46 m water depth using jacket sub-structures,
the Alpha Ventus wind farm demonstrating jackets and tripods for foundation, and the floating
wind turbine concepts, HyWind and BlueH. New concepts are under development, e.g. SWAY,
WindFloat and WindSea.
The experience so far indicates that technical challenges related to offshore installation,
operation, maintenance and repairs have been underestimated, though are now being addressed
by the industry and applied research.
Bottom-fixed wind farms, and mainly at shallow waters, are expected to dominate the near term
development, whereas industry-scale deployment of deep offshore (floating) wind farms are
expected after 2020.
A joint challenge in offshore wind is costs. The very ambitious targets for development of
offshore wind farms are only likely to be realized provided significant cost reductions. This can
be achieved through incremental improvements, e.g. gaining cost reductions through more
efficient mass-fabrication and installation procedures, reduction of risks and contingencies
through experience and better engineering tools, improved quality in critical parts and more costefficient operation and maintenance.
This topical expert meeting takes this as background, and focus on the possibilities of stepchanges in technology aiming for high reliability solutions and innovative concepts as a means
for cost reductions of offshore wind energy. These are solutions and concepts in the R&D phase
today.
Quotations
As inspiration the following quotes are offered; all from “Oceans of Opportunity” document
(EWEA, September 2009):
The future for wind turbine designs (pp 47)
In order to establish large production volumes, several pressing demands have to be met. This
can be realised through a strategy focused on producing continuous, incremental improvements
in the current basic concepts of wind turbine systems. Besides this strategy of incremental
improvement, offshore project designers and operators, for instance, are requesting the
development of completely new concepts. This second approach is also an opportunity to make
significant reductions in the cost of energy by developing innovative concepts. These two
strategies should be developed in parallel.
[...]
Improving the reliability of offshore wind turbines is paramount to the success of offshore
wind energy in the future. The larger the machine and further away from the coast, the larger the
economic loss for non-operation and associated maintenance. Vintage wind turbines often have
the same gearbox for their entire working lives. Modern wind turbines are much larger and
optimised by weight and efficiency. They need a number of major overhauls during their
lifetimes to ensure efficient operation, as does any conventional power generation plant. Wind
turbines are currently designed in such a way that the exchange of main components or sub
assemblies is difficult. More efficient and newer drive train concepts are needed to bring turbine
reliability up to the required level. A more modular build up of drive trains with more built in
redundancy could help faster, cheaper and more efficient turbine maintenance. The need for
extremely reliable machines offshore can also be an extra driver for the reliability of onshore
machines.
Innovative concepts, such as variable speed, direct-drive offshore wind turbines are currently
emerging, with the aim of limiting the number of moving parts and lowering maintenance costs,
as gearboxes are expensive to replace offshore. A multi-pole gearless machine also operates at
lower drive train speeds and thus creates less stress on components. A main challenge for these
concepts is to reduce the weight on top of the tower, in order to optimise the use of material
and limit the transport and installation costs. So far, gearless machines have been heavier and
more expensive to produce than their geared equivalent. Lighter gearless technology is now
being tested onshore.
Larger machines (5 to 10 MW), specifically designed for offshore could bring benefits in terms
of economies of scale by placing fewer larger machines on fewer foundations, or increasing the
wind farm’s power output. For example, economies of scale could also be realised by increasing
the lifetime to 30 years, provided it does not negatively affect the design.
Concepts such as two-bladed downwind turbines could emerge in the medium term. Two-bladed
machines are louder in operation making them less appropriate onshore, but not offshore. A twobladed machine would be easier to install as nacelles can be stacked with the full rotor mounted,
whereas the single blade lifts of the third blade for the bunny eared configuration are highly
dependent on calm weather. No large two-bladed offshore turbine is currently in operation.
Supply of sub-structures (pp 49)
[..]
The offshore wind industry will need to deploy upwards of 10,000 structures by 2020. The
offshore manufacturing industry cannot deliver this in its current form. The industry currently
has insufficient capacity, and the processes adapted from oil and gas manufacturing are not
capable of delivering the volumes required. Therefore the offshore wind industry must take
urgent steps to rectify this situation. In addition, the supply of substructures should not been seen
as independent from their transport and installation as an integrated approach is taken, taking
into account unique site conditions and the location of the wind farm.
Substructures represent a significant proportion of offshore development costs. In the case
described by Papalexandrou1, the foundation represents 25% (5 MW turbine) to 34% (2 MW
1
Papalexandrou, 2008: Economic analysis of offshore wind farms. KTH & Ecofys.
turbine) of investment costs in 25m water depth. Thus, novel sub-structure designs and/or
improved manufacturing processes that reduce costs will be critical to improving the
economics of offshore developments.
Objectives
The goal of the meeting is to address high reliability solutions and innovative concepts for
offshore wind turbines. Focus is on solutions and concepts under development.
As a source of further inspiration, a list of potential specific topics is added below.
- New solutions for increasing reliability, e.g. direct drive systems, hydraulic transmission,
redundancy in control systems, modular power electronic converters, systems for
preventive/condition-based maintenance.
- Innovative concepts of wind turbine and sub-structure, e.g. new methods of installation,
concrete foundations, alternative jacket-structures, vertical-axis wind turbines, more turbines
on one sub-structure, semi-submersible floaters and slender floaters, see also Figure 1.
- Review results of IEA Wind Task 23: Offshore wind energy
Figure 1: Example innovative floating offshore wind turbine concepts.
Intended audience
Participants will typically represent the following type of entities:





Universities and research organizations
Manufacturers of wind turbines
Power companies, developers and wind turbine owners
Certification institutes and consultants
Government representatives
Outcome of meeting
The outcome of the meeting is a clearer understanding of high reliability solutions and
innovative concepts for offshore wind turbines, hereunder the proceedings and a plan for future
information exchange / work within this area. Is there a need for continued information exchange
in this area (e.g. is there interest in an IEA Task on this topic, and how should this relate to new
Task 30: Offshore Comparison of Dynamic Computer Codes and Models Offshore Comparison
Collaborative (OC3) Extension Project.