Offshore Wind Energy Technology

Olimpo Anaya-Lara, John Olav Tande, Kjetil Uhlen, Karl Merz

• Publisher: Wiley
• Year: 2018
• ISBN:
  9781119097792
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Energy

A COMPREHENSIVE REFERENCE TO THE MOST RECENT ADVANCEMENTS IN OFFSHORE WIND TECHNOLOGY

Offshore Wind Energy Technology offers a reference based on the research material developed by the acclaimed Norwegian Research Centre for Offshore Wind Technology (NOWITECH) and material developed by the expert authors over the last 20 years. This comprehensive text covers critical topics such as wind energy conversion systems technology, control systems, grid connection and system integration, and novel structures including bottom-fixed and floating. The text also reviews the most current operation and maintenance strategies as well as technologies and design tools for novel offshore wind energy concepts.

The text contains a wealth of mathematical derivations, tables, graphs, worked examples, and illustrative case studies. Authoritative and accessible, Offshore Wind Energy Technology:

• Contains coverage of electricity markets for offshore wind energy and then discusses the challenges posed by the cost and limited opportunities

• Discusses novel offshore wind turbine structures and floaters

• Features an analysis of the stochastic dynamics of offshore/marine structures

• Describes the logistics of planning, designing, building, and connecting an offshore wind farm

Written for students and professionals in the field, Offshore Wind Energy Technology is a definitive resource that reviews all facets of offshore wind energy technology and grid connection.

1
Introduction

John O. Tande

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CHAPTER MENU

1. 1.1 Development of Offshore Wind Energy
2. 1.2 Offshore Wind Technology
3. 1.3 Levelized Cost of Energy
4. 1.4 Future Offshore Wind Development
5. 1.5 References

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Development of offshore wind energy is a great scientific and engineering challenge. It involves multiple disciplines, thus this textbook aims to contribute by giving concise information on design of offshore wind farms, addressing technology and power system integration. One chapter is devoted to operation and maintenance modelling. Other aspects, such as met‐ocean conditions, soil, spatial planning, impact on the environment and so on, are not part of this textbook. This chapter open by describing the historic development of offshore wind energy (Section 1.1) and continues by introducing the topics being addressed in this textbook (Section 1.2). Thereafter, follows a brief section on cost of energy calculations (Section 1.3) before the chapter is concluded with considerations on the future development of offshore wind energy (Section 1.4).

1.1 Development of Offshore Wind Energy

The argument for the development of offshore wind energy is generally for providing clean energy without any emissions of carbon dioxide (CO₂) or other greenhouse gasses and, in this way, battling climate change. Offshore wind development contributes to long‐term security of supply as a domestic renewable resource, rather than import or exhausting limited fossil fuel reserves, and can be a means of boosting industry activity with supplies for construction and operation. Many large cities are located close to the sea, hence offshore wind farms can be built in proximity to them. This can be attractive as an alternative to long transmission lines or deploying power plants on land close to large cites with high property values. The wind resource is generally much greater offshore than over land, and offshore wind farms can be built with very low negative environmental impact (WWF, 2014).

As can be concluded from the above, there are clearly many good reasons to develop offshore wind energy. But, as for any new source of energy, the market and technology needs to be matured before it can compete without any support. The technology must be proven with a professional supply chain, and developers must be able to carry out offshore wind farm projects with low risk and deliver energy at competitive cost.

The first offshore wind turbine was a 220 kW turbine installed about 250 m from shore at 6 m water depth outside Nogersund in southern Sweden in 1990. The year after, in 1991, the first offshore wind farm was installed. This was Vindeby, comprising eleven 450 kW turbines about 1 km from shore at 2–4 m water depth outside Lolland in Denmark. These early developments may seem small compared to the state of the industry today but were utterly bold and pushed the limits at their time. They demonstrated offshore wind energy to be viable and that challenges related to installation and operation of wind turbines offshore could be overcome. The development of offshore wind energy continued to be slow, however, and it was not before the turn of the century that development started to gain real momentum (Figure 1.1). In this period (2000–2015) the typical size of offshore wind farms increased from tens of MW to hundreds of MW, and wind farms were built further from shore and in deeper waters. By the end of 2015, the accumulated installed offshore wind capacity was 12.1 GW, distributed in 14 countries, with the United Kingdom top of the list with 5.1 GW, followed by Germany (3.3 GW), Denmark (1.3 GW) and China (1.0 GW) (Table 1.1).

Figure 1.1 Global accumulated offshore wind capacity since 2000.

Source: Data from Nikolaos 2004, McCarthy 2013 and GWEC 2016.

Table 1.1 Installed offshore wind capacity by the end of 2015. Data from GWEC (2016).

Country	Capacity (MW)
UK	5067
Germany	3295
Denmark	1271
PR China	1015
Belgium	712
The Netherlands	427
Sweden	202
Japan	53
Finland	26
Ireland	25
South Korea	5
Spain	5
Norway	2
Portugal	2

Almost all wind capacity built in the period (Table 1.1) was bottom fixed, with the exception of projects in Norway (Hywind, 2.3 MW, 2009), Portugal (WindFloat, 2 MW, 2...