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23 May 2023 
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  Original: English  
 
  
TRADE AND ENVIRONMENTAL SUSTAINABILITY STRUCTURED DISCUSSIONS  (TESSD)  
COMMUNICATION  FROM THE UNITED KINGDOM  
The following communication, dated 23 May 2023, is being circulated at the request of the delegation 
of the United Kingdom.  
 
_______________  
 
 
OFFSHORE WIND ENERGY  
Technical  paper by the United Kingdom  
Contents  
1   INTRODUCTION  ................................ ................................ ................................ ..........  2 
1.1   Executive summary  ................................ ................................ ................................ ... 2 
1.2   The importance of offshore wind energy in achieving climate mitigation goals  ....................  2 
1.3   Lifecycle considerations for offshore wind turbines  ................................ ..........................  3 
2   ROLE OF SERVICES  ................................ ................................ ................................ ...... 4 
2.1   Technical services  ................................ ................................ ................................ ...... 4 
2.2   Ancillary services  ................................ ................................ ................................ ....... 4 
2.3   Barriers to servic es trade  ................................ ................................ ............................  5 
3   VALUE CHAIN DIAGRAMS  ................................ ................................ ............................  5 
3.1   Wind turbine  ................................ ................................ ................................ .............  7 
3.1.1   Nacelle ................................ ................................ ................................ ..................  7 
3.1.2   Rotor  ................................ ................................ ................................ ....................  9 
3.1.3   Tower  ................................ ................................ ................................ ..................  11 
4   EXAMPLES O F SERVICES (TECHNICAL AND ANCILLARY) INVOLVED IN THE OFFSHORE 
WIND PROJECT LIFECYCLE  ................................ ................................ ............................  13 
 
 
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  1  INTRODUCTION  
1.1  Executive summary  
This paper explores the goods and services associated with the production and trade in offshore 
wind (OSW) energy. We begin by placing this study in perspective, summarising the importance of 
OSW technology in meeting climate mitigation goals, specifically  net zero. We describe 
environmental services which are notable across the OSW lifecycle, and note some barriers to trade. 
We also develop specific (though indicative) 'value chain diagrams ', describing goods and services 
across all OSW lifecycle phases. There are three value chain diagrams contained in this paper. A 
more comprehensive set of diagrams covering the full lifecycle are tabled in a separate Annex 
(INF/TE/SSD/W/26/Add.1 ). 
Our hope is to continu e to develop this report, sharing additional information with TESSD covering 
further barriers to trade and ideas for steps that can be taken to overcome them.  
This individual report follows from the UK 's earlier technical paper titled "Building our Evidenc e Base 
around Environmental Goods"1, shared with TESSD in March 2023.  
1.2  The importance of offshore wind energy in achieving climate mitigation goals  
Wind energy solutions will be important in achieving climate mitigation objectives by reducing 
greenhouse ga s emissions through displacement of thermal power generation and reducing 
operational costs compared with fossil -fuel based electricity generation . 
That wind energy makes a significant positive impact towards meeting environmental objectives is 
well understood. Reference is made below to several useful and credible resources which support 
this. We  envisage that the case for wind energy will be subject to revision, and that further evidence 
can be added to this document in future versions.  
The UN Climate Technology Centre and Network (CTCN)  clearly sets out that due to the 
renewable nature of wind energy, the large resource availability, and the relatively advanced nature 
of the technology, wind energy technologies have the potential to make a sign ificant contribution to 
climate change mitigation efforts. The uptake of wind energy can displace generation from thermal 
power plants, which can prevent rises in CO2 emissions .2  
Project Drawdown  documents the impact that offshore wind energy solutions h ave according to 
growth in energy output and avoidance of GHG emissions worldwide:  
"Offshore wind turbines growing from the current estimated 60 terawatt -hours, to  
1,850.04 –2,175.56 terawatt -hours by 2050, could avoid 10.22 –9.89 gigatons of greenhouse ga s 
emissions."  
The International Energy Association  (IEA) stress that while offshore wind represents a small 
fraction of current power generation, it is important to prioritise efforts in this area since 
improvements in technology and steep cost reductions make harnessing the near limitless potential 
of wind within our collective grasp. Indeed, the IEA have reported record growth in wind electricity 
production in 2021 (up 273  TWh or 17%) – 55% higher than for 2020, and the highest growth 
among all renewable power technologies .3 
Both the International Renewable Energy Association  (IRENA) and the IEA have said they 
expect offshore wind capacity will need to exceed 2000 GW in 2050, from just over 60 GW today to 
achieve net zero. The Global Offshore Wind Allianc e (GOWA), launched at COP27 in November 2022, 
have pledged to a rapid ramp up of offshore wind, aiming to accelerating growth to reach a total of 
 
1 INF/TE/SSD/W/23 . 
2 https://www.ctc -n.org/technologies/offshore -wind. 
3 https://www.iea.org/reports/offshore -wind-outlook -2019. INF/TE/SSD/W/ 26 
 
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  at least 380 GW installed capacity by the end of 2030. This work includes active collaboration to 
remove barri ers to the deployment of offshore wind in new and existing markets .4 
The UNIDO ITPO Tokyo STePP platform  describes the major features and advantages of a 
mid-sized wind turbine .5 A common problem for the deployment of wind energy in regions prone to 
periodic high wind conditions is that the turbines can become damaged during extreme weather 
events or other natural disasters. The platform documents a medium -sized turbine which is d esigned 
to be easily transportable, relatively simple to install, with strong lightning and earthquake 
protection, and resistant to extreme and unstable winds (beyond the requirements of the relevant 
IEC standard).  
Similarly, the World Intellectual Proper ty Organisation 's (WIPO) Marketplace for 
Sustainable Technologies  contains entries for typhoon -proof wind turbines6, among a variety of 
other wind energy technologies .7 This resource shows not only that there are a wide array of benefits 
to be realised f rom the uptake of these technologies, but also that these technologies frequently 
have a high Technology Readiness Level (TRL). This resource also documents a wide variety of 
cooperation types under which wind energy technology transfer is possible under v oluntary but 
mutually agreed terms.  
1.3  Lifecycle considerations for offshore wind turbines  
The benefits to the environment from the uptake of wind energy are clear from the sources above. 
Industry is now homing in on the outstanding lifecycle challenges assoc iated with select components 
to maximise the environmental compatibility of this technology. A selection of these challenges has 
been outlined below.  
The disposal of turbine blades poses a challenge during the end -of-life stage of a turbine 's lifecycle. 
Whilst 85 -90% of wind turbines ' total mass can be recycled, this is not the case for the blades, which 
often end up in landfill.8,9 Turbine blades are made from reinforced fibres (typically glass or carbon 
fibres) and a polymer matrix. Whilst they are non -toxic and landfill safe, commercially viable 
recycling methods are limited.10 
The majority of currently viable recycling methods are some form of 'down -cycling ', where the new 
material produced is of lower quality than the original material. Many recycling  methods that produce 
higher quality material involve much higher energy costs, however more research is needed for 
accurate lifecycle assessment of these techniques.11,12 
New materials are under development which can be used for wind turbine blades that a re more 
easily recycled into useful products, however it remains to be seen whether these materials will be 
economically viable at scale.13 In the meantime, the challenge remains regarding how current 
 
4 https://www.irena.org/News/pressreleases/2022/Nov/Nine -new-countries -sign-up-for-Global -
Offshore -Wind-Alliance -at-COP27 . 
5 http://www.unido.or.jp/en/technology_db/1685/ . 
6 https://wipogreen.wipo.int/wipogreen -
database/articles/147595?queryFilters.0.field=TECH_FIELD_ID&queryFilters.0.valu e=54&queryFilters.1.field=T
ECH_TYPE&queryFilters.1.value=5&type=BASIC&query=&pagination.size=30&pagination.page=0&sort.0.field=
CREATED_AT&sort.0.direction=DESC . 
7 https://wipogreen.wipo.int/wipogreen -
database/search?queryFilt ers.0.field=TECH_FIELD_ID&queryFilters.0.value=54&queryFilters.1.field=TECH_TYP
E&queryFilters.1.value=5&type=BASIC&query=&pagination.size=30&pagination.page=0&&sort.0.field=CREATE
D_AT&sort.0.direction=DESC . 
8 https://cleangridalliance.org/blog/137/wind -turbine -recycling -and-disposal . 
9 WindEurope, "Accelerating Wind Turbine Blade Circularity ", 2020.  
10 https://windeurope.org/newsroom/press -releases/wind -industry -calls-for-europe -wide-ban-on-
landfilling -turbine -blades/ . 
11 Beauson, J., Laurent, A., Rudolph, D.P. and Jensen, J.P., 2022. The complex end -of-life of wind 
turbine blades: A review of the European context. Renewable and Sustainable Energy Reviews , 155, 
p. 111847.  
12 Sustainable decommissioning: Wind Turbine Blade Recyc ling, Catapult Offshore Renewable Energy  
13 https://www.scientificamerican.com/article/recycled -wind-turbines -could -be-made -into-plexiglass -
diapers -or-gummy -bears/ . INF/TE/SSD/W/ 26 
 
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  turbine blades are disposed of when they are decommissioned, with a predicted 43 million tonnes 
of blade waste being produced worldwide by 2050.14 
2  ROLE OF SERVICES  
2.1  Technical services  
There are a wide variety of services (many of which are highly technical) in the generation of 
Offshore Wind (OSW). These services are intrinsic to every stage, from the development and 
management of an OSW project, through to the manufacture of wind turbi nes, balancing the plant, 
installation and commissioning of turbines and wind farms. Section 4 (below) details the technical 
service activities that contribute to elements of an OSW project.  
Many of these technical services are specific to a particular st age of the OSW lifecycle. Engineering 
and construction are key elements in the installation and assembly of wind turbines and offshore 
substation construction. Maintenance and repair services are needed at later stages of the OSW 
lifecycle. They are often complementary to goods used in an OSW project and are typically 
undertaken by the original system supplier who will chart vessels for the purpose.15 
2.2  Ancillary services  
Both industry and academics have acknowledged the scope of environmental services needs to be 
broader than the 'core' services as designated by the CPC 94 classification (OECD,  2022; Swedish 
National Board of Trade, 2014; KPMG, 2021). Environmentally related services, particularly those 
relating to the development, deployment, implementation,  maintenance, and decommissioning of 
environmental goods, contribute to a green end -use, but are not included in the classical definition 
of environmental services.  
As OSW has developed, the services that are necessary to enable the success of these proje cts 
similarly grows. Services such as research and development, financial services, insurance, and 
maintenance are utilised in OSW projects. As section  4 demonstrates , PBS and digital services are 
used across the development, installation, maintenance, and  decommissioning of OSW. However, 
these are not classified as environmental services under the CPC 94 definition (OECD, 2022).  
Expertise is required throughout the early stages of the project lifecycle, including the development 
of environmental strategy, and modelling feasibility, risk and resilience. A variety of services then 
support the establishment and day -to-day running of the project and its operation, including; the 
creation of a Special Purpose Vehicle, accounting and tax services, asset managers,  operation and 
maintenance providers, and technical consultants. For example:   
• Legal services:  Legal services and consultants are key at many stages of an OSW project. A 
special purpose vehicle  (SPV)  is typically set up at project initiation which manages the 
development process and subcontracts work to a range of specialist consultancies. The SPV is 
a legal entity, which invests in and owns the wind farm project. Tasks such as obtaining 
planning consent, land leases are all supported by various professiona l business services.  
• Financial services:  Projects can be financed in different ways. OSW is capital -intensive, with 
large upfront costs for equipment  and costs then decreasing to operate and maintain. A case 
study of the company UK Wind1 – a UK offshore w ind farm – shows one example of this. The 
project is sized on a circa 80% debt to 20% equity ratio. The debt is secured over all material 
project contracts and assets. Insurers sit behind the lenders.16 Greencoat UK Wind PLC is a 
UK investment fund investi ng in UK Wind farms. The fund itself utilises adjacent services, in 
this case BDO; a firm providing accountancy and business advice. BDO acted as a reporting 
accountant, and covered many aspects from due diligence, reviewing forecast financial 
 
14 Wind Turbine Blade Waste in 2050. Authors: Pu Liu and Claire Y Barlow. University of Cambridge 
Institute for Manufacturing . 
15 https://www.thecrownestate.co.uk /media/2861/guide -to-offshore -wind-farm-2019.pdf . 
16 https://www.scor.com/sites/default/files/2021 -04/Offshore_Wind_Farm_Finance -CaseStudy_0.pdf . INF/TE/SSD/W/ 26 
 
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  information,  and providing assurance on financial information of assets being acquired by the 
fund.17  
• Consultancy services:  Packages of work are commissioned to environmental and 
engineering consultancies – key work need to be completed in the development stage of OSW, 
such as environmental surveying before the project can progress to the next stage.  
• R&D services: Research an d development services are key to both creating new energy 
projects and to improving existing energy projects. Research interests contribute to 
pre-project design and manufacture for example, improving turbine reliability as well as 
development of novel in stallation technologies to reduce costs and risks. R&D also contributes 
once the project is up and running, such as improving drone techniques and data analysis for 
better operations and maintenance.18 
2.3  Barriers to services trade  
The adoption of ICT has boo sted the tradability of services and many of the services above can now 
be delivered using computer networks.19 However, there remain regulatory barriers such as 
restrictions to cross -border data flows and commercial presence requirements that restrict dig itally 
delivered services. The OECD Digital Services Trade Restrictiveness Index (DSTRI)  shows there are 
cross-cutting barriers that inhibit or completely prohibit firms ' ability to supply services using 
electronic networks, and these have been increasing.  This is primarily driven by restrictions related 
to interconnection on communication infrastructures and restrictions affecting connectivity.  
The OECD find large benefits from removing barriers to digital services trade and the case is even 
stronger in e merging economies where the benefits of reform deliver greater export gains.20 
Services barriers tend to be behind rather than on the border, and are often a result of balancing 
competing domestic policy challenges. For example, services used in the offsho re wind sector can 
be subject to cross -cutting barriers to investment and restrictions to the movement of people. In 
engineering, near a third of all restrictions captured in the OECD Services Trade Restrictiveness 
Index (STRI) relates to quotas, labour ma rket test and limitations on duration of stay for business 
persons. Almost half of the countries in the OECD STRI impose some form of nationality or citizenship 
requirements for senior managers and board of directors which restricts trade in services inclu ding 
finance and insurance. Free trade agreements are good examples of where countries have removed 
or eased these restrictions.  
Professional services such as accounting, architecture, legal and engineering services are also 
subject to restrictions on rec ognition of qualifications which have a negative impact on international 
trade in these services. STRI date shows some countries impose nationality of citizenship 
requirements to practice architecture, and/or lack laws or regulation to establish processes for 
recognising qualifications gained abroad. Countries can facilitate trade in services through 
cooperation on recognition of qualifications, and can also encourage relevant bodies to discuss the 
potential inclusion of sustainability skills as a requireme nt for recognition to better promote 
environmental goals.  
3  VALUE CHAIN DIAGRAMS  
We introduced value chain diagrams for environmental goods in our technical paper titled "Building 
our Evidence Base around Environmental Goods"21, as a powerful tool for organ ising key information 
relating to goods.  
 
17 https://www.cityoflondon.gov.uk/supporting -businesses/economic -research/research -publications/in -
service -of-sustainable -infrastructure . 
18 https://ore.catapult.org.uk/what -we-do/supply -chain -growth/torc -2/. 
19 See OECD, WTO, IMF Handbook for Measuring Digital Trade Volume 1 . 
20 OECD (2023) 'Of bytes and trade: Quantifying the impact of digitalisation on trade ', 
https://www.oecd -ilibrary.org/trade/of -bytes-and-trade -quantifying -the-impact -of-digitalisation -on-
trade_11889f2a -en. 
21 INF/TE/SSD/W/23 . INF/TE/SSD/W/ 26 
 
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  Value chain diagrams visualise and describe a range of manufacturing activities or production 
processes that are applied to raw material inputs and intermediate products as these are 
transformed into final goods, th at combine to form technological solutions to environmental 
challenges. These diagrams describe both goods and services, production, and trade. They can 
therefore drive research into trade barriers and connected problems and be annotated with additional 
information.  
By bringing together these different kinds of information, they can deepen our understanding of the 
relationship between goods, services, production, trade – and the environment, and can help us 
develop better and more coordinated trade, industrial, and environmental policies.  
The value chain diagrams in this section have been annotated with commodity codes for illustrative 
purposes only . Simple names of products are generally insufficient for seeking formal classification 
opinions because  they do not contain an explanation of the product 's essential characteristics. These 
characteristics would need to be compared with the explanatory notes of the harmonised system to 
seek a formal opinion.  
The information within these diagrams is sourced from the UK Offshore Renewable Energy Catapult 
Project's guide to an offshore wind farm .22 The aim of the guide is to help develop a greater 
understanding of the components and processes involved in the development UK offshore wind 
farms. This publication builds on that by applying a value chain framework to the contents of the 
guide, which can be annotated with relevant trade policy information, as illustrated by the 
commodity codes. The guide itself contains further qualitative information about each stage of the 
wind farm lifecycle23, and presents a full  cost breakdown in £/MW .24 It also contains a supply chain 
map of UK offshore wind farms in the UK, Europe, and around the world .25  
More value chain diagrams are contained in the Annex  to this paper , document 
INF/TE/SSD/W/26/Add.1 . 
 
Value chain diagrams – key: 
 
Chevron  
Colour  Meaning  
  Manufacturing activity or production process involved in either the manufacture or 
assembly of a wind turbine  
  Input product, intermediate product, final product, or a service deliverable in any 
stage of an offshore wind farm 's lifecycle  
  
 
22 https://guidetoanoffshorewindfarm.com/ . 
23 https://guidetoanoffshorewindfarm.com/lifecycle . 
24 https://guidetoanoffshorewindfarm.com/wind -farm-costs. 
25 https://guidetoanoffshorewindfarm.com/supply -chain -map.  
  INF/TE/SSD/W/2 6 
 
- 7 - 3.1  Wind turbine  
The turbine  converts kinetic energy from the wind into three -phase AC electrical energy.  
3.1.1   Nacelle  
The nacelle supports  the Rotor and converts the rotational energy from the rotor into three -phase AC electrical energy.  
• Bedplate:  supports the drive train and the rest of  the nacelle components and transfers loads from the rotor to the tower.  
• Main bearing:  supports the rotor and transfers some of the rotor loading to the nacelle Bedplate.  
• Main shaft:  transfers torque from the rotor to the gearbox or, for some direct drive designs, the generator. It is supported at the rotor end by the 
main shaft bearing and at the other end either by the gearbox / generator or separately mounted bearing.  
• Gearbox:  converts rotor torque at a speed of 5 -15 rpm to a speed of up to about 600  rpm for a medium speed gearbox and 1500  rpm for a high -
speed gearbox for conversion to electrical energy by the generator.  
• Generator:  converts mechanical energy to electrical energy.  
• Power take -off: receives electrical energy from the generator and adjusts voltage and frequency for onward transfer to the wind farm distribu tion 
system.  
• Control system:  provides supervisory control (including health monitoring) and active power and load control in order  to optimise wind turbine life 
and revenue generation, while meeting externally imposed requirements.  
• Yaw system:  orients the nacelle to the wind direction during operation.  
• Yaw bearing:  connects the nacelle and tower, enabling the yaw system to orient the  nacelle to any wind direction during operation.  
• Auxiliary systems:  facilitate ongoing unattended operation of the wind turbine for the vast majority of the time, and support planned maintenanc e, 
which typically should be only on an annual basis.  
• Nacelle c over:  provides weatherproof protection to the nacelle components plus support and access to external components such as coolers, wi nd 
measurement equipment and lighting protection devices.  
• Small engineering components:  make up the rest of the nacelle assem bly. 
• Structural fasteners (either bolts or studs):  are used in a range of critical bolted joints, for example connecting rotor to main shaft, main bearing 
housings to nacelle bedplate and yaw bearing to the underside of nacelle bedplate.  
• Condition monitori ng systems:  provide additional health checking and failure prediction capability.  
   
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- 9 - 3.1.2   Rotor  
The rotor extracts kinetic  energy from the air and converts this into rotational energy in the drive train.  
• Blades: capture the energy in the wind and transfer torque and other unwanted loads to the drive train and rest of the turbine.  
• Hub: connects the blades to the main shaft.  
• Blade bearings:  enable adjustment of blade pitch angle to control power output from the turbine, minimise loads and start/stop turbine as req uired.  
• Pitch system:  adjusts the pitch angle of the blades to control power output from the turbine, minimise loads a nd start/stop turbine as required.  
• Spinner: provides environmental protection to the hub assembly and access into the hub and blades for maintenance personnel.  
• Rotor auxiliary systems:  may be incorporated to lubricate bearings and provide condition monitoring and advanced control inputs.  
• Fabricated steel components:  often required  to stiffen the blade bearing support and provide a connection for hydraulic pitch system actuators.  
 
   
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- 11 - 3.1.3   Tower  
The tower is typically a tubular steel structure that supports the nacelle. It also provides access to the nacelle and houses electrical and control equipment. Also 
provides shelter and storage for safety equipment.  
• Steel:  the most commonly used material for the manufacture of towers.  
• Tower internals:  provide means of access, lighting and safety for maintenance and service personnel, plus means of transferring hand tools and  
components to the nacelle. They provide support for control and electrical cables and housing of switch -gear, transform ers and other elements of 
power take -off. Tower internals also provide storage for survival equipment. A tuned damper may be located at the top of the tower to ai de damping 
of tower and structure resonances.  
 
   
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- 13 - 4  EXAMPLES OF SERVICES (TECHNICAL AND ANCILLA RY) INVOLVED IN THE OFFSHORE WIND PROJECT LIFECYCLE  
 
 
This is indicative of examples of services (technical and ancillary) that may be involved in an Offshore Wind project lifecyc le. It should not be considered as 
exhaustive and is a work in progress.  
 
 
__________