Offshore wind power

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Offshore wind power or offshore wind energy is the use of wind farms constructed in bodies of water, usually in the ocean, to harvest wind energy to generate electricity. Higher wind speeds are available offshore compared to on land, so offshore wind power’s electricity generation is higher per amount of capacity installed,[1] and NIMBY opposition to construction is usually much weaker.

Unlike the typical use of the term "offshore" in the marine industry, offshore wind power includes inshore water areas such as lakes, fjords and sheltered coastal areas as well as deeper-water areas. Most offshore wind farms employ fixed-foundation wind turbines in relatively shallow water. As of 2020, floating wind turbines for deeper waters are in the early phase of development and deployment.

At the end of 2018, the total worldwide offshore wind power capacity was 23.1 gigawatt (GW).[2] All the largest offshore wind farms are currently in northern Europe, especially in the United Kingdom and Germany, which together account for over two-thirds of the total offshore wind power installed worldwide. As of September 2018, the 659 MW Walney Extension in the United Kingdom is the largest offshore wind farm in the world.[3] The Hornsea Wind Farm under construction in the United Kingdom will become the largest when completed, at 1,200 MW. Other projects are in the planning stage, including Dogger Bank in the United Kingdom at 4.8 GW, and Greater Changhua in Taiwan at 2.4 GW.[4]

The cost of offshore wind power has historically been higher than that of onshore wind generation,[5] but costs have been decreasing rapidly in recent years to $78/MWh in 2019.[6] Offshore wind power in Europe has been price-competitive with conventional power sources since 2017.[7] Offshore wind generation grew at over 30 percent per year in the 2010s. As of 2020, offshore wind power has become a significant part of northern Europe power generation, though it remained less than 1 percent of overall world electricity generation.[8]

History[edit]

5,000
10,000
15,000
20,000
25,000
30,000
1998
2002
2006
2010
2014
2019
Global cumulative offshore capacity (MW).
Sources: GWEC (2011–2019)[9][10][11][2][12] and EWEA (1998–2010)[13]

Capacity[edit]

An illustration of a hypothetical offshore wind farm in 1977

Europe is the world leader in offshore wind power, with the first offshore wind farm (Vindeby) being installed in Denmark in 1991.[14] In 2009, the average nameplate capacity of an offshore wind turbine in Europe was about 3 MW, and the capacity of future turbines was expected to increase to 5 MW.[14]

A 2013 comprehensive review of the engineering aspects of turbines like the sizes used onshore, including the electrical connections and converters, considered that the industry had in general been overoptimistic about the benefits-to-costs ratio and concluded that the "offshore wind market doesn’t look as if it is going to be big".[15][16] In 2013, offshore wind power contributed to 1,567 MW of the total 11,159 MW of wind power capacity constructed that year.[17]

By January 2014, 69 offshore wind farms had been constructed in Europe with an average annual rated capacity of 482 MW.[18] The total installed capacity of offshore wind farms in European waters reached 6,562 MW.[18] The United Kingdom had by far the largest capacity with 3,681 MW. Denmark was second with 1,271 MW installed and Belgium was third with 571 MW. Germany came fourth with 520 MW, followed by the Netherlands (247 MW), Sweden (212 MW), Finland (26 MW), Ireland (25 MW), Spain (5 MW), Norway (2 MW) and Portugal (2 MW).[18]

At the end of 2015, 3,230 turbines at 84 offshore wind farms across 11 European countries had been installed and grid-connected, making a total capacity of 11,027 MW.[19][20]

Outside of Europe, the Chinese government had set ambitious targets of 5 GW of installed offshore wind capacity by 2015 and 30 GW by 2020 that would eclipse capacity in other countries. However, in May 2014 the capacity of offshore wind power in China was only 565 MW.[21] Offshore capacity in China increased by 832 MW in 2016, of which 636 MW were made in China.[22]

The offshore wind construction market remains quite concentrated. By the end of 2015, Siemens Wind Power had installed 63% of the world's 11 GW[23] offshore wind power capacity; Vestas had 19%, Senvion came third with 8% and Adwen 6%.[24][2] About 12 GW of offshore wind power capacity was operational, mainly in Northern Europe, with 3,755 MW of that coming online during 2015.[25] As of 2020 90% of the offshore global market was represented by European companies.[26]

By 2017, the installed offshore wind power capacity worldwide was 20 GW.[27] In 2018, offshore wind provided just 0.3% of the global electricity supply.[28] Nevertheless, just in 2018 an additional amount of 4.3 GW of offshore wind capacity was employed on a worldwide scale[28]. In Denmark, 50% of the electricity was supplied by wind energy in 2018 out of which 15% was offshore.[29]

Costs[edit]

In 2010, the US Energy Information Agency said "offshore wind power is the most expensive energy generating technology being considered for large scale deployment".[5] The 2010 state of offshore wind power presented economic challenges significantly greater than onshore systems, with prices in the range of 2.5-3.0 million Euro/MW.[30] That year, Siemens and Vestas were turbine suppliers for 90% of offshore wind power, while Ørsted A/S (then named DONG Energy), Vattenfall and E.on were the leading offshore operators.[1]

In 2011, Ørsted estimated that while offshore wind turbines were not yet competitive with fossil fuels, they would be in 15 years. Until then, state funding and pension funds would be needed.[31] At the end of 2011, there were 53 European offshore wind farms in waters off Belgium, Denmark, Finland, Germany, Ireland, the Netherlands, Norway, Sweden and the United Kingdom, with an operating capacity of 3,813 MW,[32] while 5,603 MW was under construction.[33] Offshore wind farms worth €8.5 billion ($11.4 billion) were under construction in European waters in 2011.[34]

In 2012, Bloomberg estimated that energy from offshore wind turbines cost €161 (US$208) per MWh.[35]

Costs of offshore wind power are decreasing much faster than expected. By 2016, four contracts (Borssele and Kriegers) were already below the lowest of the predicted 2050 prices.[36][37]

Future development[edit]

Projections for 2020 estimate an offshore wind farm capacity of 40 GW in European waters, which would provide 4% of the European Union's demand of electricity.[38] The European Wind Energy Association has set a target of 40 GW installed by 2020 and 150 GW by 2030.[14] Offshore wind power capacity is expected to reach a total of 75 GW worldwide by 2020, with significant contributions from China and the United States.[1]

The Organisation for Economic Co-operation and Development (OECD) predicted in 2016 that offshore wind power will grow to 8% of ocean economy by 2030, and that its industry will employ 435,000 people, adding $230 billion of value.[39]

The European Commission expects that offshore wind energy will be of increasing importance in the future, as offshore wind is part of its Green Deal.[40] The development of the full potential of Europe’s offshore wind energy is one of the key actions in the Clean Energy section of the Green Deal.[40]

By 2050, the expectation is that the installed offshore wind power capacity will reach 1550 GW on a worldwide scale.[27] Compared to the capacity of 2017 that corresponds to an 80-fold increase.[27]

One of the advancements that characterises the current development within the offshore industry are technologies that allow for offshore wind projects further off the shore where wind availability is higher. In particular, the adoption of floating foundation technologies has proved to be a promising technology for unlocking the wind potential on deeper waters.[41]

Types of offshore wind turbines[edit]

Fixed foundation offshore wind turbines[edit]

Progression of expected wind turbine evolution to deeper water
Tripods foundation for offshore wind farms in 2008 in Wilhelmshaven, Germany

Almost all currently operating offshore wind farms employ fixed foundation turbines, with the exception of a few pilot projects. Fixed foundation offshore wind turbines have fixed foundations underwater, and are installed in relatively shallow waters of up to 50–60 m.[42]

Types of underwater structures include monopile, tripod, and jacketed, with various foundations at the sea floor including monopile or multiple piles, gravity base, and caissons.[42] Offshore turbines require different types of bases for stability, according to the depth of water. To date a number of different solutions exist:[14][43]

  • Most foundations are monopile (single column) base, six meters in diameter, is used in waters up to 30 meters deep.
  • Conventional steel jacket structures, as used in the oil and gas industry, in water 20–80 m deep.
  • Gravity base structures, for use at exposed sites in water 20–80 m deep.
  • Tripod piled structures, in water 20–80 m deep.
  • Tripod suction caisson structures, in water 20–80 m deep.

Monopiles up to 11 m diameter at 2,000 tonnes can be made, but the largest so far are 1,300 tons which is below the 1,500 tonnes limit of some crane vessels. The other turbine components are much smaller.[44]

The tripod pile substructure system is a new concept developed to reach deeper waters than with the shallow water systems, up to 60 m. This technology consists of three monopiles linked together through a joint piece at the top. The main advantage of this solution is the simplicity of the installation, which is done by installing three monopiles and then adding the upper joint.[45]

Tripod is an innovative concept that consists on a central pipe that lies on a tripod tubular frame configuration at its bottom part. This uses three small seabed driven piles at each leg of the tripod to link it to the seabed. The main advantage of the tripod system is that it has a larger base, which decreases its risk of getting overturned. Due to the large dimensions the installation process is more difficult and increases the cost.[45]

A steel jacket structure comes from an adaptation to the offshore wind industry of concepts that have been in use in the oil and gas industry for decades. Their main advantage lies in the possibility of reaching higher depths (up to 80m). Their main limitations are due to the high construction and installation costs.[45]

Floating offshore wind turbines[edit]

Blue H Technologies - World's First Floating Wind Turbine

For locations with depths over about 60–80 m, fixed foundations are uneconomical or technically unfeasible, and floating wind turbine anchored to the ocean floor are needed.[46][47][48] Blue H Technologies installed the world's first floating wind turbine in 2007.[49][50] Hywind is the world's first full-scale floating wind turbine, installed in the North Sea off Norway in 2009.[51] Hywind Scotland, commissioned in October 2017, is the first operational floating wind farm, with a capacity of 30 MW. Other kinds of floating turbines have been deployed, and more projects are planned.

Vertical axis offshore wind turbines[edit]

Although the great majority of onshore and all large-scale offshore wind turbines currently installed are horizontal axis, vertical axis wind turbines have been proposed for use in offshore installations. Thanks to the installation offshore and their lower center of gravity, these turbines can in principle be built bigger than horizontal axis turbines, with proposed designs of up to 20 MW capacity per turbine.[52] This could improve the economy of scale of offshore wind farms.[52] However, there are no current large-scale demonstrations of this technology.

Economics[edit]

Comparison of the levelized cost of electricity of offshore wind power compared to other sources in Germany in 2018[53]

The advantage of locating wind turbines offshore is that the wind is much stronger off the coasts, and unlike wind over land, offshore breezes can be strong in the afternoon, matching the time when people are using the most electricity. Offshore turbines can also be located close to the load centers along the coasts, such as large cities, eliminating the need for new long-distance transmission lines.[54] However, there are several disadvantages of offshore installations, related to more expensive installation, difficulty of access, and harsher conditions for the units.

Locating wind turbines offshore exposes the units to high humidity, salt water and salt water spray which negatively affect service life, cause corrosion and oxidation, increase maintenance and repair costs and in general make every aspect of installation and operation much more difficult, time-consuming, more dangerous and far more expensive than sites on land. The humidity and temperature is controlled by air conditioning the sealed nacelle.[55] Sustained high-speed operation and generation also increases wear, maintenance and repair requirements proportionally.

The cost of the turbine represents just one third to one half[30] of total costs in offshore projects today, the rest comes from infrastructure, maintenance, and oversight. Costs for foundations, installation, electrical connections and operation and maintenance (O&M) are a large share of the total for offshore installations compared to onshore wind farms. The cost of installation and electrical connection also increases rapidly with distance from shore and water depth.[52]

Other limitations of offshore wind power are related to the still limited number of installations. The offshore wind industry is not yet fully industrialized, as supply bottlenecks still exist as of 2017.[56]

Investment costs[edit]

Offshore wind farms tend to have larger turbines when compared to onshore installations, and the trend is towards a continued increase in size. Economics of offshore wind farms tend to favor larger turbines, as installation and grid connection costs decrease per unit energy produced.[52] Moreover, offshore wind farms do not have the same restriction in size of onshore wind turbines, such as availability of land or transportation requirements.[52]

Operating costs[edit]

Operational expenditures for wind farms are split between Maintenance (38%), Port Activities (31%), Operation (15%), License Fees (12%), and Miscellaneous Costs (4%).[57]

Operation and maintenance costs typically represent 53% of operational expenditures, and 25% - 30% of the total lifecycle costs for offshore wind farms. O&Ms are considered one of the major barriers for further development of this resource.

Maintenance of offshore wind farms is much more expensive than for onshore installations. For example, a single technician in a pickup truck can quickly, easily and safely access turbines on land in almost any weather conditions, exit his or her vehicle and simply walk over to and into the turbine tower to gain access to the entire unit within minutes of arriving onsite. Similar access to offshore turbines involves driving to a dock or pier, loading necessary tools and supplies into boat, a voyage to the wind turbine(s), securing the boat to the turbine structure, transferring tools and supplies to and from boat to turbine and turbine to boat and performing the rest of the steps in reverse order. In addition to standard safety gear such as a hardhat, gloves and safety glasses, an offshore turbine technician may be required to wear a life vest, waterproof or water-resistant clothing and perhaps even a survival suit if working, sea and atmospheric conditions make rapid rescue in case of a fall into the water unlikely or impossible. Typically at least two technicians skilled and trained in operating and handling large power boats at sea are required for tasks that one technician with a driver's license can perform on land in a fraction of the time at a fraction of the cost.

Cost of energy[edit]

Cost for installed offshore turbines fell 30% to $78/MWh in 2019, a more rapid drop than other types of renewable energy.[6] It has been suggested that innovation at scale could deliver 25% cost reduction in offshore wind by 2020.[58] Offshore wind power market plays an important role in achieving the renewable target in most of the countries around the world.

Auctions in 2016 for future projects have reached costs of €54.5 per megawatt hour (MWh) at the 700 MW Borssele 3&4[59] due to government tender and size,[60] and €49.90 per MWh (without transmission) at the 600 MW Kriegers Flak.[61]

In September 2017 contracts were awarded in the United Kingdom for a strike price of £57.50 per MWh making the price cheaper than nuclear and competitive with gas.[62]

In September 2018 contracts were awarded for Vineyard Wind, Massachusetts, USA at a cost of between $65-$74 per MWh.[63][64]

Offshore wind resources[edit]

Map of Global Offshore Wind Speeds (Global Wind Atlas 3.0)

Offshore wind resources are by their nature both huge in scale and highly dispersed, considering the ratio of the planet’s surface area that is covered by oceans and seas compared to land mass. Wind speeds offshore are known to be considerably higher than for the equivalent location onshore due to the absence of land mass obstacles and the lower surface roughness of water compared to land features such as forests and savannah, a fact that is illustrated by global wind speed maps that cover both onshore and offshore areas using the same input data and methodology. For the North Sea, wind turbine energy is around 30 kWh/m2 of sea area, per year, delivered to grid. The energy per sea area is roughly independent of turbine size.[65]

The technical exploitable resource potential for offshore wind is a factor of the average wind speed and water depth, as it is only possible to generate electricity from offshore wind resources where turbines can be anchored. Currently, fixed foundation offshore wind turbines can be installed up to around 50 meters of sea depth. Beyond that, floating foundation turbines would be required, potentially allowing installation at depths of up to 1 kilometer based on currently proposed technologies.[66] Based on an analysis of viable water depths and wind speeds over 7 m/s, it has been estimated that there is over 17 terawatt (TW) of offshore wind technical potential in just the 50 countries studied, not including most OECD countries such as Australia, Japan, the United States or Western Europe. Well-endowed countries such as Argentina and China have almost 2TW and 3TW of potential respectively, illustrating the vast potential of offshore wind in such locations.[67]

Planning and permitting[edit]

A number of things are necessary in order to attain the necessary information for planning the commissioning of an offshore wind farm. The first information required is offshore wind characteristics. Additional necessary data for planning includes water depth, currents, seabed, migration, and wave action, all of which drive mechanical and structural loading on potential turbine configurations. Other factors include marine growth, salinity, icing, and the geotechnical characteristics of the sea or lake bed.

Existing hardware for measurements includes Light Detection and Ranging (LIDAR), Sonic Detection and Ranging (SODAR), radar, autonomous underwater vehicles (AUV), and remote satellite sensing, although these technologies should be assessed and refined, according to a report from a coalition of researchers from universities, industry, and government, supported by the Atkinson Center for a Sustainable Future.[68]

Because of the many factors involved, one of the biggest difficulties with offshore wind farms is the ability to predict loads. Analysis must account for the dynamic coupling between translational (surge, sway, and heave) and rotational (roll, pitch, and yaw) platform motions and turbine motions, as well as the dynamic characterization of mooring lines for floating systems. Foundations and substructures make up a large fraction of offshore wind systems, and must take into account every single one of these factors.[68] Load transfer in the grout between tower and foundation may stress the grout, and elastomeric bearings are used in several British sea turbines.[69]

Corrosion is also a serious problem and requires detailed design considerations. The prospect of remote monitoring of corrosion looks very promising using expertise utilised by the offshore oil/gas industry and other large industrial plants.

Some of the guidelines for designing offshore wind farms are IEC 61400-3,[70][71][72] but in the US several other standards are necessary.[73] In the EU, different national standards are to be streamlined into more cohesive guidelines to lower costs.[74] The standards require that a loads analysis is based on site-specific external conditions such as wind, wave and currents.[75]

The planning and permitting phase can cost more than $10 million, take 5–7 years and have an uncertain outcome. The industry is putting pressure on governments to improve the processes.[76][77] In Denmark, many of these phases have been deliberately streamlined by authorities in order to minimize hurdles,[78] and this policy has been extended for coastal wind farms with a concept called ’one-stop-shop’.[79] The United States introduced a similar model called "Smart from the Start" in 2012.[80]

In the European Union, the revised Renewable Energy Directive of 2018 has simplified the permitting process to help initiate wind projects.[26]

Legal framework[edit]

The installation and operation of offshore wind turbines are regulated in both national and international law. The relevant international legal framework is UNCLOS (United Nations Convention on the Law of the Sea) which regulates the rights and responsibilities of the States in regards to the use of the oceans.[81] The maritime zone the offshore wind turbines are located in determines which regulatory rules apply.

In the territorial waters (up to 12 nautical miles from the baseline of the coast) the coastal State has full sovereignty[81] and therefore, the regulation of offshore wind turbines are fully under national jurisdiction.

The exclusive economic zone (up to 200 nautical miles off the baseline) is not part of the State’s territory but is subject to the coastal State’s exclusive jurisdiction and control for selected purposes, one of which is the production of energy from winds.[81] This means that within this zone, the coastal State has the right to install and operate offshore wind farms and to establish safety zones around them that must be respected by all ships, as long as a due notice about the installation has been given. Also, neither installations nor safety zones can interfere with sea lanes that are considered essential for international navigation.[81]

Beyond the exclusive economic zones are the high seas, or the international waters.[81] Within this zone the purpose of producing energy is not explicitly mentioned as a high seas freedom and the legal status of offshore wind facilities is therefore unclear. In academia, it has been argued that the uncertainty of the legal status of offshore wind facilities on the high seas could become an object of interstate disputes over the rights of use.[82] As a solution, it has been suggested that offshore wind facilities could be incorporated as a high seas freedom by being considered as ships or artificial islands, installations and structures.[82]

As of 2020, energy production from winds on the high seas is not yet technically feasible due to the complications that follow from deeper water.[83] However, the advancing technology of floating wind turbines is a step towards the realization of deepwater wind projects.[83]

Turbine construction materials considerations[edit]

Since offshore wind turbines are located in oceans and large lakes, the materials used for the turbines have to be modified from the materials used for land based wind turbines and optimized for corrosion resistance to salt water and the new loading forces experienced by the tower being partially submerged in water. With one of the main reasons for interest in offshore wind power being the higher wind speeds, some of the loading differences will come from higher shearing forces between the top and bottom of the wind turbine due to differences in wind speeds. There should also be considerations for the buffeting loads that will be experienced by the waves around the base of the tower, which converges on the use of steel tubular towers for offshore wind applications.[84]

Since there’s constant exposure to salt and water for offshore wind turbines, the steel used for the monopile and turbine tower must be treated for corrosion resistance, especially at the base of the tower in the “splash zone” for waves breaking against the tower and in the monopile. Two techniques that can be used include cathode protection and the use of coatings to reduce corrosion pitting, which is a common source for hydrogen induced stress cracking.[85] For cathode protection, galvanized anodes are attached to the monopile and have enough of a potential difference with the steel to be preferentially corroded over the steel used in the monopile. Some coatings that have been applied to offshore wind turbines include hot dip zinc coatings and 2-3 epoxy coatings with a polyurethane topcoat.[85]

Installation[edit]

Several foundation structures for offshore wind turbines in a port

Specialized jackup rigs (Turbine Installation Vessels) are used to install foundation and turbine. As of 2019 the next generation of vessels are being built, capable of lifting 3-5,000 tons to 160 meters.[86]

A large number of monopile foundations have been used in recent years for economically constructing fixed-bottom offshore wind farms in shallow-water locations.[87][88] Each uses a single, generally large-diameter, foundation structural element to support all the loads (weight, wind, etc.) of a large above-surface structure.

The typical construction process for a wind turbine sub-sea monopile foundation in sand includes using a pile driver to drive a large hollow steel pile 25 m deep into the seabed, through a 0.5 m layer of larger stone and gravel to minimize erosion around the pile. These piles can be 4 m in diameter with approximately 50mm thick walls. A transition piece (complete with pre-installed features such as boat-landing arrangement, cathodic protection, cable ducts for sub-marine cables, turbine tower flange, etc.) is attached to the now deeply driven pile, the sand and water are removed from the centre of the pile and replaced with concrete. An additional layer of even larger stone, up to 0.5 m diameter, is applied to the surface of the seabed for longer-term erosion protection.[88]

For the ease of installing the towers and connecting them to the seabed, they are installed in two parts, the portion below the water surface and the portion above the water.[84] The two portions of the tower are joined by a transition piece which is filled with a grouted connection. The grouted connected helps transfer the loads experienced by the turbine tower to the more stable monopile foundation of the turbine. One technique for strengthening the grout used in the connections is to include weld beads known as shear keys along the length of the grout connection to prevent any sliding between the monopile and the tower.[89]

Grid connection[edit]

An offshore structure for housing an HVDC converter station for offshore wind parks is being moved by a heavy-lift ship in Norway.

There are several different types of technologies that are being explored as viable options for integrating offshore wind power into the onshore grid. The most conventional method is through high-voltage alternating current (HVAC) transmission lines. HVAC transmission lines are currently the most commonly used form of grid connections for offshore wind turbines.[90] However, there are significant limitations that prevent HVAC from being practical, especially as the distance to offshore turbines increases. First, HVAC is limited by cable charging currents,[90] which are a result of capacitance in the cables. Undersea AC cables have a much higher capacitance than overhead AC cables, so losses due to capacitance become much more significant, and the voltage magnitude at the receiving end of the transmission line can be significantly different from the magnitude at the receiving end. In order to compensate for these losses, either more cables or reactive compensation must be added to the system. Both of these add costs to the system.[90] Additionally, because HVAC cables have both real and reactive power flowing through them, there can be additional losses.[91] Because of these losses, underground HVAC lines are limited in how far they can extend. The maximum appropriate distance for HVAC transmission for offshore wind power is considered to be around 80 km.[90]

Using high-voltage direct current (HVDC) cables has been a proposed alternative to using HVAC cables. HVDC transmission cables are not affected by the cable charging currents and experience less power loss because HVDC does not transmit reactive power.[92] With less losses, undersea HVDC lines can extend much farther than HVAC. This makes HVDC preferable for siting wind turbines very far offshore. However, HVDC requires power converters in order to connect to the AC grid. Both line commutated converters (LCCs) and voltage source converters (VSCs) have been considered for this. Although LCCs are a much more widespread technology and cheaper, VSCs have many more benefits, including independent active power and reactive power control.[92] New research has been put into developing hybrid HVDC technologies that have a LCC connected to a VSC through a DC cable.[92]

In order to transport the energy from offshore wind turbines to onshore energy plants, cabling has to be placed along the ocean floor. The cabling has to be able to transfer large amounts of current efficiently which requires optimization of the materials used for the cabling as well as determining cable paths for the use of a minimal amount of cable materials.[84] One way to reduce the cost of the cables used in these applications is to convert the copper conductors to aluminum conductors, however the suggested replacement brings up an issue of increased cable motion and potential damage since aluminum is less dense than copper.

Maintenance[edit]

Offshore wind turbines of the Rødsand Wind Farm in the Fehmarn Belt, the western part of the Baltic Sea between Germany and Denmark (2010)

Turbines are much less accessible when offshore (requiring the use of a service vessel or helicopter for routine access, and a jackup rig for heavy service such as gearbox replacement), and thus reliability is more important than for an onshore turbine.[1] Some wind farms located far from possible onshore bases have service teams living on site in offshore accommodation units.[93] To limit the effects of corrosion on the blades of a wind turbine, a protective tape of elastomeric materials is applied, though the droplet erosion protection coatings provide better protection from the elements.[94]

A maintenance organization performs maintenance and repairs of the components, spending almost all its resources on the turbines. The conventional way of inspecting the blades is for workers to rappel down the blade, taking a day per turbine. Some farms inspect the blades of three turbines per day by photographing them from the monopile through a 600mm lens, avoiding to go up.[95] Others use camera drones.[96]

Because of their remote nature, prognosis and health-monitoring systems on offshore wind turbines will become much more necessary. They would enable better planning just-in-time maintenance, thereby reducing the operations and maintenance costs. According to a report from a coalition of researchers from universities, industry, and government (supported by the Atkinson Center for a Sustainable Future),[68] making field data from these turbines available would be invaluable in validating complex analysis codes used for turbine design. Reducing this barrier would contribute to the education of engineers specializing in wind energy.

Decommissioning[edit]

As the first offshore wind farms reach their end of life, a demolition industry develops to recycle them at a cost of DKK 2-4 million per MW, to be guaranteed by the owner.[97] The first offshore wind farm to be decommissioned was Yttre Stengrund in Sweden in November 2015, followed by Vindeby in 2017 and Blyth in 2019.

Environmental impact[edit]

Offshore wind farms have very low global warming potential per unit of electricity generated, comparable to that of onshore wind farms. Offshore installations also have the advantage of limited impact of noise and on the landscape compared to land-based projects. Furthermore, in a few local cases there is evidence that offshore wind installations have contributed to the restoration of damaged ecosystems by functioning as artificial reefs.[98]

While the offshore wind industry has grown dramatically over the last several decades, there is still a great deal of uncertainty associated with how the construction and operation of these wind farms affect marine animals and the marine environment.[99] Common environmental concerns associated with offshore wind developments include:

  • The risk of seabirds being struck by wind turbine blades or being displaced from critical habitats;
  • The underwater noise associated with the installation process of driving monopile turbines into the seabed;
  • The physical presence of offshore wind farms altering the behavior of marine mammals, fish, and seabirds with attraction or avoidance;
  • The potential disruption of the nearfield and farfield marine environment from large offshore wind projects.[99]

Because offshore wind is a relatively new industry, there is not yet any evidence on the long-term environmental impacts of offshore wind activities nor any studies on the cumulative effects on several marine activities in the same area.[100]

The Tethys database provides access to scientific literature and general information on the potential environmental effects of offshore wind energy.[99]

Largest offshore wind farms[edit]

Four offshore wind farms are in the Thames Estuary area: Kentish Flats, Gunfleet Sands, Thanet and London Array. The latter was the largest in the world until September 2018.
Offshore wind farms with a capacity of at least 400 MW
Wind farm Location Site coordinates Capacity
(MW)
Turbines & model Commissioning
date
Refs
Hornsea 1  United Kingdom 53°53′06″N 1°47′28″E / 53.885°N 1.791°E / 53.885; 1.791 (Hornsea 1) 1,218 174 x Siemens SWT-7.0-154 2019 [101][102]
Walney Extension  United Kingdom 54°5′17″N 3°44′17″W / 54.08806°N 3.73806°W / 54.08806; -3.73806 (Walney Extension) 659 40 x MHI-Vestas 8.25 MW
47 x Siemens Gamesa 7 MW
2018 [103]
London Array  United Kingdom 51°38′38″N 01°33′13″E / 51.64389°N 1.55361°E / 51.64389; 1.55361 (London Array) 630 175 × Siemens SWT-3.6-120 2013 [104][105][106]
Gemini Wind Farm  Netherlands 54°2′10″N 05°57′47″E / 54.03611°N 5.96306°E / 54.03611; 5.96306 (Gemini Wind Farm) 600 150 × Siemens SWT-4.0 2017 [107][108][109][110]
Beatrice  United Kingdom 58°7′48″N 3°4′12″W / 58.13000°N 3.07000°W / 58.13000; -3.07000 (Beatrice Wind Farm) 588 84 × Siemens SWT-7.0-154 2019 [111]
Gode Wind (phases 1+2)  Germany 54°04′N 7°02′E / 54.067°N 7.033°E / 54.067; 7.033 (Gode Wind I+II) 582 97 x Siemens SWT-6.0-154 2017 [112][113]
Gwynt y Môr  United Kingdom 53°27′00″N 03°35′00″W / 53.45000°N 3.58333°W / 53.45000; -3.58333 (Gwynt y Môr) 576 160 × Siemens SWT-3.6-107 2015 [114]
Race Bank  United Kingdom 53°16′N 0°50′E / 53.267°N 0.833°E / 53.267; 0.833 (Race Bank) 573 91 x Siemens SWT-6.0-154 2018 [115][116]
Greater Gabbard  United Kingdom 51°52′48″N 1°56′24″E / 51.88000°N 1.94000°E / 51.88000; 1.94000 (Greater Gabbard wind farm) 504 140 × Siemens SWT-3.6-107 2012 [117][118][119]
Hohe See  Germany 54°26′N 6°19′E / 54.433°N 6.317°E / 54.433; 6.317 497 71 x Siemens SWT-7.0-154 2019 [120]
Borkum Riffgrund 2  Germany 53°57′7″N 6°29′17″E / 53.95194°N 6.48806°E / 53.95194; 6.48806 (Borkum Riffgrund 2) 450 56 x MHI Vestas V164-8.0 MW 2019 [121]
Horns Rev 3  Denmark 55°49′N 7°42′E / 55.817°N 7.700°E / 55.817; 7.700 (Horns Rev 3) 407 49 x MHI Vestas V164-8.3 MW 2019 [122]
Dudgeon  United Kingdom 53°14′56″N 1°23′24″E / 53.24889°N 1.39000°E / 53.24889; 1.39000 (Dudgeon Offshore Wind Farm) 402 67 × Siemens SWT-6.0-154 2017 [123]
Veja Mate  Germany 54°19′1″N 5°52′15″E / 54.31694°N 5.87083°E / 54.31694; 5.87083 (Veja Mate Wind Farm) 402 67 × Siemens SWT-6.0-154 2017 [124][125]
Anholt  Denmark 56°36′00″N 11°12′36″E / 56.60000°N 11.21000°E / 56.60000; 11.21000 (Anholt Offshore Wind Farm) 400 111 × Siemens SWT-3.6-120 2013 [126][127][128][129]
BARD Offshore 1  Germany 54°22′0″N 5°59′0″E / 54.36667°N 5.98333°E / 54.36667; 5.98333 (BARD Offshore 1) 400 80 × BARD 5.0MW 2013 [130][131][132]
Global Tech I [de]  Germany 54°30′00″N 6°21′30″E / 54.50000°N 6.35833°E / 54.50000; 6.35833 (Global Tech I) 400 80 × Areva Multibrid M5000 5.0MW 2015 [133]
Rampion  United Kingdom 50°40′N 0°06′W / 50.667°N 0.100°W / 50.667; -0.100 (Rampion) 400 116 x MHI Vestas V112-3.45 MW 2018 [134]
Binhai North  China 34°40′04″N 120°21′29″E / 34.66778°N 120.35806°E / 34.66778; 120.35806 (Binhai North Wind) 400 100 x Siemens SWT-4.0-120 2018 [135]

Projects[edit]

Most of the current projects are in European and East Asian waters.

There are also several proposed developments in North America. Projects are under development in the United States in wind-rich areas of the East Coast, Great Lakes, and Pacific coast. In January 2012, a "Smart for the Start" regulatory approach was introduced, designed to expedite the siting process while incorporating strong environmental protections. Specifically, the Department of Interior approved “wind energy areas” off the coast where projects can move through the regulatory approval process more quickly.[136] The first offshore wind farm in the USA is the 30-megawatt, 5 turbine Block Island Wind Farm which was commissioned in December 2016.[137][138] Many sportfishermen and marine biologists believe the bases of the five, 6-megawatt wind turbines off of Block Island are acting as an artificial reef.[139]

Another offshore wind farm that is in the planning phase is off the coast of Virginia Beach. On 3 August 2018, Dominion Energy announced its two wind turbine pilot program that will be 27 miles offshore from Virginia Beach. The area is undergoing a survey that will last for 4–6 weeks.[140]

Canadian wind power in the province of Ontario is pursuing several proposed locations in the Great Lakes, including the suspended[141] Trillium Power Wind 1 approximately 20 km from shore and over 400 MW in capacity.[142] Other Canadian projects include one on the Pacific west coast.[143]

India is looking at the potential of offshore wind power plants, with a 100 MW demonstration plant being planned off the coast of Gujarat (2014).[144] In 2013, a group of organizations, led by Global Wind Energy Council (GWEC) started project FOWIND (Facilitating Offshore Wind in India) to identify potential zones for development of off-shore wind power in India and to stimulate R & D activities in this area. In 2014 FOWIND commissioned Center for Study of Science, Technology and Policy (CSTEP) to undertake pre-feasibility studies in eight zones in Tamil Nadu which have been identified as having potential.[145]

Offshore wind power by country[edit]

Offshore wind turbines near Copenhagen, Denmark

Most of offshore wind farms are currently in northern Europe. The United Kingdom and Germany alone accounted for roughly two thirds of the total offshore wind power capacity installed worldwide in 2016. Other countries, such as China, are rapidly expanding their offshore wind power capacity.

List of countries by cumulative installed offshore wind power capacity (MW)[2][12]
Rank Country 2016 2017 2018 2019
1 United Kingdom 5,156 6,651 7,963 9,723
2 Germany 4,108 5,411 6,380 7,493
3 China 1,627 2,788 4,588 6,838
4 Denmark 1,271 1,268 1,329 1,703
5 Belgium 712 877 1,186 1,556
6 Netherlands 1,118 1,118 1,118 1,118
7 Sweden 202 202 192 191
8 Taiwan 0 8 8 128
9 Vietnam 99 99 99 99
10 Japan 60 65 65 85
11 South Korea 35 38 73 73
12 Finland 32 92 87 71
13 United States 30 30 30 30
14 Ireland 25 25 25 25
15 Spain 5 5 5 5
16 Norway 2 2 2 2
17 France 0 2 2 2
World total 14,482 18,658 23,140 29,142

See also[edit]

References[edit]

  1. ^ a b c d Madsen & Krogsgaard. Offshore Wind Power 2010 Archived 30 June 2011 at the Wayback Machine BTM Consult, 22 November 2010. Retrieved: 22 November 2010.
  2. ^ a b c d "Global Wind Report 2018" (PDF). gwec.net. Global Wind Energy Council (GWEC). Retrieved 22 May 2019.
  3. ^ Vaughan, Adam (6 September 2018). "World's largest offshore windfarm opens off Cumbrian coast". The Guardian. Retrieved 6 September 2018.
  4. ^ "Orsted clears Taiwan hurdle". reNEWS - Renewable Energy News. 6 December 2017. Retrieved 7 December 2017.
  5. ^ a b Levelized Cost of New Generation Resources in the Annual Energy Outlook 2011. Released 16 December 2010. Report of the US Energy Information Administration (EIA) of the U.S. Department of Energy (DOE).
  6. ^ a b Lee, Andrew (22 October 2019). "Offshore wind power price plunges by a third in a year". Recharge | Renewable energy news and articles.
  7. ^ "After a decade of dithering, the US east coast went all in on offshore wind power this week". Retrieved 29 September 2018.
  8. ^ Reed, Stanley (4 June 2020). "A New Weapon Against Climate Change May Float". The New York Times. Retrieved 10 June 2020.
  9. ^ "GWEC Global Wind Statistics 2014" (PDF). Global Wind Energy Council. 10 February 2015.
  10. ^ "Global Wind Statistics 2015" (PDF). Global Wind Energy Council (GWEC). 10 February 2016. Retrieved 14 April 2017.
  11. ^ "OFFSHORE WIND | GWEC". www.gwec.net. Retrieved 5 August 2017.
  12. ^ a b "Global Wind Report 2019". GWEC.
  13. ^ "Wind in our Sails, A report by the European Wind Energy Association - 2011" (PDF). European Wind Energy Association. 2011. p. 11. Retrieved 27 February 2015.
  14. ^ a b c d Environmental and Energy Study Institute (October 2010). "Offshore Wind Energy" (PDF).
  15. ^ Platt, Jim (2013). "The offshore wind energy nano-industry". Nanotechnology Perceptions. 9 (2): 91–95. doi:10.4024/N04PL13A.ntp.09.02.
  16. ^ "The offshore wind energy nano-industry". Retrieved 20 May 2016.
  17. ^ "Wind in power 2013 European statistics" The European Wind Energy Association, 2014
  18. ^ a b c The European offshore wind industry - key trends and statistics 2013 ,The European Wind Energy Association, 2014
  19. ^ "Wind in Power: 2014 European statistics". European Wind Energy Association (EWEA). Retrieved 16 March 2014.
  20. ^ Ho, Andrew (2015). The European offshore wind industry - key trends and statistics 2015 (PDF). European Wind Energy Association. p. 10. Retrieved 29 April 2019.
  21. ^ "Detailed appraisal of the offshore wind industry in China". The Carbon Trust. May 2014. Retrieved 22 July 2014.
  22. ^ "China tops offshore turbine chart". reNEWS - Renewable Energy News. 22 February 2017. Retrieved 26 February 2017.
  23. ^ Ryan, Joe (2 May 2016). "A U.S. State Has Key to $10 Billion Offshore Wind Boom". Bloomberg.com. Retrieved 2 June 2016.
  24. ^ Jessica Shankleman (28 April 2016). "World's Biggest Windmills Now Make Jumboi Jets Look Tiny". Bloomberg.com. Retrieved 2 June 2016.
  25. ^ "Global Wind Industry Hits Record 62 GW Installed In 2015". CleanTechnica. 3 February 2016.
  26. ^ a b European Commission (22 April 2020). "Onshore and offshore wind". European Commission. Retrieved 28 May 2020.
  27. ^ a b c DNV GL (2019). Energy Transition Outlook 2019. A global and regional forecast to 2050. https://eto.dnvgl.com/2019: DNV GL. p. 124.CS1 maint: location (link)
  28. ^ a b IEA (2019). Offshore Wind Outlook 2019. https://www.iea.org/reports/offshore-wind-outlook-2019: International Energy Agency. p. 15.CS1 maint: location (link)
  29. ^ IEA (2020). Offshore Wind Outlook 2019. https://www.iea.org/reports/offshore-wind-outlook-2019: International Energy Agency. p. 16.CS1 maint: location (link)
  30. ^ a b Lindvig, Kaj. The installation and servicing of offshore wind farms p6 A2SEA, 16 September 2010. Accessed: 9 October 2011.
  31. ^ Nymark, Jens. Seaturbines competitive in 15 years Archived 16 November 2011 at the Wayback Machine Børsen, 15 November 2011. Accessed: 10 December 2011.
  32. ^ Justin Wilkes et al. The European offshore wind industry key 2011 trends and statistics European Wind Energy Association, January 2012. Accessed: 26 March 2012.
  33. ^ 17 EU countries planning massive offshore wind power ROV world, 30 November 2011. Accessed: 10 December 2011.
  34. ^ Tildy Bayar (30 September 2011). "Wind Energy Markets: Experts See Solid Offshore Growth". Renewable Energy World.
  35. ^ Bakewell, Sally (29 October 2012). "Largest Offshore Wind Farm Generates First Power in U.K." Bloomberg. Retrieved 19 December 2012.
  36. ^ Stiesdal, Henrik (21 December 2016). "Midt i en disruptionstid". Ingeniøren. Retrieved 21 December 2016. Real prices have moved to half of what the experts predicted
  37. ^ "Price diagram: Real and predicted prices for offshore wind power".
  38. ^ Tillessen, Teena (2010). "High demand for wind farm installation vessels". Hansa International Maritime Journal. Vol. 147 no. 8. pp. 170–171.
  39. ^ The Ocean Economy in 2030, pp.205-212. OECD iLibrary, 27 April 2016. ISBN 9264251723 . Web read
  40. ^ a b European Commission (2020). "A European Green Deal". European Commission. Retrieved 28 May 2020.
  41. ^ IEA (2019). Offshore Wind Outlook 2019. https://www.iea.org/reports/offshore-wind-outlook-2019: International Energy Agency. pp. 22–23.CS1 maint: location (link)
  42. ^ a b "Challenges in design of foundations for offshore wind turbines". The E&T Energy and Power Hub. The E&T Energy and Power Hub. 9 August 2017. Archived from the original on 7 December 2017. Retrieved 7 December 2017.
  43. ^ "Offshore wind foundation shift hinges on serial build gains | New Energy Update". analysis.newenergyupdate.com. 15 May 2019. Archived from the original on 5 October 2019.
  44. ^ "Installation Vessels: Reaching the Limit and Beyond". 27 March 2017. Retrieved 19 April 2017.
  45. ^ a b c Perez-Collazo, C (2 January 2015). "A review of combined wave and offshore wind energy". Elsevier.
  46. ^ "Classification and Certification of Floating Offshore Wind Turbines" Archived 3 December 2013 at the Wayback Machine Bureau Veritas, November 2010. Retrieved: 16 August 2012.
  47. ^ Elaine Kurtenbach. "Japan starts up offshore wind farm near Fukushima" The Sydney Morning Herald, 12 November 2013. Accessed: 11 November 2013.
  48. ^ "Japan: Experimental Offshore Floating Wind Farm Project" OffshoreWind, 11 October 2013. Accessed: 12 October 2013.
  49. ^ "Floating Wind Turbines". Floating Wind Turbines. Retrieved 21 July 2020.
  50. ^ "Blue H Technologies Launches World's First Floating Wind Turbine". MarineBuzz. Retrieved 21 July 2020.
  51. ^ Madslien, Jorn (5 June 2009). "Floating wind turbine launched". BBC News. Retrieved 14 September 2009.
  52. ^ a b c d e Sun, Xiaojing; Huang, Diangui; Wu, Guoqing (May 2012). "The current state of offshore wind energy technology development". Energy. 41 (1): 298–312. doi:10.1016/j.energy.2012.02.054.
  53. ^ "Studie: Stromgestehungskosten erneuerbare Energien - März 2018". Fraunhofer ISE. 2018. Retrieved 2 April 2018.
  54. ^ "Wind Power". New York Times. 27 January 2002.
  55. ^ Prinds, Karsten (20 April 2011). "Where offshore wind was invented". LORC. Archived from the original on 29 April 2016. Retrieved 27 February 2017.
  56. ^ Poulsen, Thomas; Lema, Rasmus (1 June 2017). "Is the supply chain ready for the green transformation? The case of offshore wind logistics". Renewable and Sustainable Energy Reviews. 73: 758–771. doi:10.1016/j.rser.2017.01.181.
  57. ^ Röckmann C., Lagerveld S., Stavenuiter J. (2017) Operation and Maintenance Costs of Offshore Wind Farms and Potential Multi-use Platforms in the Dutch North Sea. In: Buck B., Langan R. (eds) Aquaculture Perspective of Multi-Use Sites in the Open Ocean. Springer, Cham
  58. ^ "Offshore Wind Accelerator". The Carbon Trust. Retrieved 22 July 2014.
  59. ^ "Oil & Gas Giant to Build Dutch Borssele III & IV Offshore Wind Farms". Offshore Wind. 12 December 2016. Retrieved 14 December 2016.
  60. ^ "Tender design, output gains key to DONG's record-low Borssele 1&2 offshore bid price". 17 August 2016. Archived from the original on 17 September 2016. Retrieved 17 September 2016.
  61. ^ Steel, William (9 November 2016). "Vattenfall wins Kriegers Flak with record €49.90/MWh". Recharge. Archived from the original on 10 November 2016. Retrieved 10 November 2016.
  62. ^ "Offshore wind cheaper than nuclear as auction smashes expectations". 11 September 2017. Retrieved 29 September 2018.
  63. ^ "A Stunningly Low Price for Offshore Wind: Massachusetts Moves Forward". 26 September 2018. Retrieved 29 September 2018.
  64. ^ "First Large US Offshore Wind Project Sets Record-Low Price Starting at $74 per MWh". August 2018. Retrieved 29 September 2018.
  65. ^ Stiesdal, Henrik. "Pi and turbines - a useful context" Original, in Danish Ingeniøren, 13 March 2015. Accessed: 13 March 2015.
  66. ^ ESMAP. 2019. "Global: Expanding Offshore Wind to Emerging Markets". Washington, DC: World Bank. Accessed: 30 April 2020
  67. ^ ESMAP. 2020. "Offshore Wind Technical Potential by Country": Maps and Tabular Data. Accessed: 30 April 2020.
  68. ^ a b c Zehnder, Alan; Warhaft, Zellman, eds. (2011). "University Collaboration on Wind Energy" (PDF). Cornell University. Retrieved 13 January 2016.
  69. ^ Tramontana, Tea (31 October 2012). "Overcoming problems with crumbling grout". LORC. Archived from the original on 12 May 2016. Retrieved 27 February 2017.
  70. ^ "Wind turbines Part 3: Design requirements for offshore wind turbines" Austrian Standards International. Retrieved: 16 August 2012.
  71. ^ International Standard IEC 61400-3 International Electrotechnical Commission, August 2005. Accessed: 12 March 2011.[dead link]
  72. ^ Quarton, D.C. "An international design standard for offshore wind turbines: IEC 61400-3" Archived 21 July 2011 at the Wayback Machine Garrad Hassan, 2005. Accessed: 12 March 2011.
  73. ^ Musial, W. D.; Sheppard, R. E.; Dolan, D.; Naughton, B. "Development of Offshore Wind Recommended Practice for U.S. Waters" National Renewable Energy Laboratory, April 2013. Accessed: 20 November 2013. OSTI ID: 1078076
  74. ^ "Archived copy". Archived from the original on 9 August 2016. Retrieved 6 June 2016.CS1 maint: archived copy as title (link)
  75. ^ Jonkman, J.M. "Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine" Technical Report NREL/TP-500-41958 page 75, NREL November 2007. Retrieved: 25 June 2012.
  76. ^ Jamie D. (11 June 2009). "N.J. must make wind farm permitting process as quick and easy as possible | Commentary | NewJerseyNewsroom.com - Your State. Your News". NewJerseyNewsroom.com. Retrieved 6 July 2013.
  77. ^ [1] Subtask 1: Critical Deployment Issues at the Wayback Machine (archived 28 August 2009)
  78. ^ Streamline Renewable Energy Policy and make Australia a World Leader Energy Matters, 11 August 2010. Retrieved: 6 November 2010.
  79. ^ "Nearshore wind turbines in Denmark"[permanent dead link] (in Danish). Danish Energy Agency, June 2012. Retrieved: 26 June 2012.
  80. ^ "Smart from the Start" Bureau of Ocean Energy Management. Accessed: 20 November 2013.
  81. ^ a b c d e United Nations (10 December 1982). "United Nations Convention on the Law of the Sea" (PDF). United Nations. Retrieved 28 May 2020.
  82. ^ a b Elsner, Paul & Suarez, Suzette (2019). "Renewable energy from the high seas: Geo-spatial modelling of resource potential and legal implications for developing offshore wind projects beyond the national jurisdiction of coastal States". Energy Policy. 128: 919–929 – via Elsevier Science Direct.CS1 maint: multiple names: authors list (link)
  83. ^ a b IEA (2019). Offshore Wind Outlook 2019. https://www.iea.org/reports/offshore-wind-outlook-2019: International Energy Agency. p. 23.CS1 maint: location (link)
  84. ^ a b c Chong, Ng (3 March 2016). Offshore wind farms : technologies, design and operation. Ng, Chong,, Ran, Li. Duxford, UK: Elsevier, WP Woodhead Publishing. ISBN 978-0-08-100780-8. OCLC 944186047.CS1 maint: date and year (link)
  85. ^ a b Black, Anders Rosborg; Mathiesen, Troels; Hilbert, Lisbeth Rischel (12 May 2015). "Corrosion Protection of Offshore Wind Foundations". NACE International. Cite journal requires |journal= (help)
  86. ^ Lars Paulsson, Jeremy Hodges, and Chris Martin (13 May 2019). "Offshore Wind Will Need Bigger Boats. Much Bigger Boats". Bloomberg.CS1 maint: multiple names: authors list (link)
  87. ^ Offshore Wind Turbine Foundations Archived 28 February 2010 at the Wayback Machine, 2009-09-09, accessed 12 April 2010.
  88. ^ a b Constructing a turbine foundation Archived 21 May 2011 at the Wayback Machine Horns Rev project, Elsam monopile foundation construction process, accessed 12 April 2010]
  89. ^ Tziavos, Nikolaos I.; Hemida, Hassan; Metje, Nicole; Baniotopoulos, Charalampos (8 June 2016). "Grouted connections on offshore wind turbines: a review" (PDF). Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics. 169 (4): 183–195. doi:10.1680/jencm.16.00004. ISSN 1755-0777.
  90. ^ a b c d Daniel, John; Liu, Shu; Ibanez, Eduardo; Pennock, Ken; Reed, Gregory; Hanes, Spencer. "National Offshore Wind Energy Grid Interconnection Study Executive Summary" (PDF). Retrieved 1 May 2019.
  91. ^ Anaya-Lara, Olimpo; Campos-Gaona, David; Moreno-Goytia, Edgar; Adam, Grain (10 April 2014). Grid Integration of Offshore Wind Farms – Case Studies. Wiley. doi:10.1002/9781118701638.ch5. ISBN 9781118701638.
  92. ^ a b c Torres-Olguin, Raymundo; Molinas, Marta; Undeland, Tore (October 2012). "Offshore Wind Farm Grid Integration by VSC Technology With LCC-Based HVDC Transmission". IEEE Transactions on Sustainable Energy. 3 (4): 899. Bibcode:2012ITSE....3..899T. doi:10.1109/TSTE.2012.2200511.
  93. ^ Accommodation Platform Archived 19 July 2011 at the Wayback Machine DONG Energy, February 2010. Retrieved: 22 November 2010.
  94. ^ Valaker, E.A.; Armada, S.; Wilson, S. (2015). "Droplet Erosion Protection Coatings for Offshore Wind Turbine Blades". Energy Procedia. 80: 263–275. doi:10.1016/j.egypro.2015.11.430.
  95. ^ Bjørn Godske (2 June 2016). "Dong bruger supertele til vingeinspektion". Ingeniøren. Retrieved 5 June 2016.
  96. ^ "3 Ways to Inspect a Blade". E.ON energized. Retrieved 5 June 2016.
  97. ^ "Aldrende havmølleparker åbner marked for klog nedrivning". Ingeniøren. 20 February 2016. Retrieved 20 May 2016.
  98. ^ Wilson, Jennifer C., Mike Elliott, Nick D. Cutts, Lucas Mander, Vera Mendao, Rafael Perez-Dominguez & Anna Phelps (2010). "Coastal and Offshore Wind Energy Generation: Is It Environmentally Benign?". Energies. 13: 1383–1422.CS1 maint: multiple names: authors list (link)
  99. ^ a b c "Environmental Effects of Wind and Marine renewable Energy". Tethys. 2017.
  100. ^ Bergström, Lena, Lena Kautsky, Torleif Malm, Rutger Rosenberg, Magnus Wahlberg, Nastassja Åstrand, Capetillo and Dan Wilhelmsson (2014). "Effects of offshore wind farms on marine wildlife - a generalised impact assessment". Environ. 9: 1–12.CS1 maint: multiple names: authors list (link)
  101. ^ "DONG Tables Hornsea Project One Offshore Construction Schedule". Offshore Wind. Archived from the original on 20 April 2018. Retrieved 20 April 2018.
  102. ^ "World's Largest Offshore Wind Farm Fully Up and Running". Offshore Wind. 30 January 2020. Retrieved 3 February 2020.
  103. ^ "Archived copy". Archived from the original on 6 September 2018. Retrieved 6 September 2018.CS1 maint: archived copy as title (link)
  104. ^ "London Array's own website announcement of commencement of offshore works" (PDF). londonarray.com. Archived (PDF) from the original on 22 July 2011. Retrieved 8 March 2011.
  105. ^ Wittrup, Sanne. First foundation Archived 9 March 2011 at the Wayback Machine Ing.dk, 8 March 2011. Accessed: 8 March 2011.
  106. ^ "London Array - The Project". londonarray.com. Archived from the original on 21 February 2014. Retrieved 10 June 2015.
  107. ^ "Archived copy". Archived from the original on 10 April 2018. Retrieved 8 May 2017.CS1 maint: archived copy as title (link)
  108. ^ "The 600-MW Gemini offshore wind farm is successfully up & running". Windpower Engineering & Development. Archived from the original on 21 January 2019. Retrieved 12 February 2019.
  109. ^ "Archived copy". Archived from the original on 21 January 2019. Retrieved 8 May 2017.CS1 maint: archived copy as title (link)
  110. ^ "Gemini". 4coffshore.com. Archived from the original on 24 January 2016. Retrieved 4 September 2015.
  111. ^ "Oleg Strashnov Installs First Beatrice Jacket Foundation". Offshore Wind. Archived from the original on 7 October 2017. Retrieved 18 October 2017.
  112. ^ "Gode Wind foundation installed successfully". 4coffshore.com. Archived from the original on 24 January 2016. Retrieved 4 September 2015.
  113. ^ "DONG Energy Inaugurates 582 Megawatt Gode Wind I & 2 Offshore Wind Farms". CleanTechnica. Archived from the original on 16 September 2017. Retrieved 3 July 2017.
  114. ^ "World's second largest offshore wind farm opens off coast of Wales". Wales Online. Archived from the original on 19 June 2015. Retrieved 18 June 2015.
  115. ^ "Full power at Race Bank Offshore Wind Farm". orsted.com. Archived from the original on 12 October 2018. Retrieved 2 February 2018.
  116. ^ "Innovation Installs First Foundation at Race Bank". offshorewind.biz/. Archived from the original on 2 July 2016. Retrieved 2 July 2016.
  117. ^ "UK: Greater Gabbard Offshore Wind Farm Generates Power". Archived from the original on 11 October 2012. Retrieved 7 September 2012.
  118. ^ "Offshore Wind Farms 2008" (PDF). EWEA. 2 February 2009. Archived (PDF) from the original on 19 April 2009. Retrieved 4 February 2009.
  119. ^ "SSE plc - The UK's broadest-based energy company". scottish-southern.co.uk. Archived from the original on 11 January 2011. Retrieved 10 June 2015.
  120. ^ "Foundation first at Hohe See". reNEWS - Renewable Energy News. 17 April 2018. Archived from the original on 19 April 2018. Retrieved 20 April 2018.
  121. ^ "MHI Vestas Sets Up Borkum Riffgrund 2 Base in Emden". Offshore Wind. Archived from the original on 20 April 2018. Retrieved 20 April 2018.
  122. ^ "Horns Rev 3 offshore wind farm Archived 2016-10-22 at the Wayback Machine" Vattenfall, 27 June 2016. Accessed: 29 October 2016.
  123. ^ Ltd, Renews (4 October 2017). "Dudgeon hits CfD milestone". reNEWS - Renewable Energy News.
  124. ^ "World's Largest OW Jack-Up Vessel Installs World's Heaviest Monopile at Veja Mate OWF". Archived from the original on 17 June 2016. Retrieved 6 June 2016.
  125. ^ "Construction complete for 402-MW Veja Mate offshore wind park". Renewables Now. Archived from the original on 21 January 2019. Retrieved 31 May 2017.
  126. ^ "VIPs cut ribbon at 400MW Anholt Archived 2013-09-07 at the Wayback Machine" Recharge News, 4 September 2013. Accessed: 4 September 2013.
  127. ^ Jan Bjerre Lauridsen & Søren Andersen. "Queen says Good Wind to giant turbines Archived 2013-09-13 at the Wayback Machine" Berlingske, 4 September 2013. Accessed: 4 September 2013.
  128. ^ "All turbines at Anholt Offshore wind farm now operational" (Press release). DONG Energy. 20 June 2013. Archived from the original on 6 October 2013. Retrieved 27 August 2013.
  129. ^ Anholf Offshore wind farm in 4C Offshore Archived 27 June 2012 at the Wayback Machine Retrieved 27 August 2013
  130. ^ "BARD 1 (4c)". 4coffshore.com. Archived from the original on 24 January 2016. Retrieved 10 June 2015.
  131. ^ Rösler eröffnet Offshore-Windpark Bard 1 Archived 28 August 2013 at the Wayback Machine Retrieved 26 August 2013
  132. ^ German Federal Minister Inaugurates BARD Offshore 1 Archived 30 August 2013 at the Wayback Machine Retrieved 26 August 2013
  133. ^ "Global Tech I officially inaugurated". sunwindenergy.com/. Archived from the original on 11 September 2015. Retrieved 4 September 2015.
  134. ^ "Rampion Offshore Wind Farm Hits Full Stride". Offshore Wind. Archived from the original on 18 April 2018. Retrieved 3 May 2018.
  135. ^ "SPIC Binhai North H2 400MW". www.4coffshore.com. Archived from the original on 30 July 2018. Retrieved 26 November 2018.
  136. ^ Kit Kennedy (2 February 2012). "Offshore Wind One Step Closer to Reality in the Mid-Atlantic". Renewable Energy World.
  137. ^ "America Is Finally Getting Its First Offshore Wind Farm. Conservatives Are Trying to Make Sure It's the Last". New Republic. 14 May 2015. Retrieved 15 May 2015.
  138. ^ "Block Island Wind Farm - Deepwater Wind". Deepwater Wind. Retrieved 20 May 2016.
  139. ^ Prevost, Lisa (4 November 2019). "In Rhode Island, offshore wind farm emerging as popular fishing spot". Energy News Network. Retrieved 28 April 2020.
  140. ^ "Offshore wind energy heading to waters off Virginia Beach". WVEC. Retrieved 14 August 2018.
  141. ^ Offshore wind development hits a snag in Ontario Archived 9 January 2012 at the Wayback Machine Alberta Oil Magazine, April 2011. Accessed: 29 September 2011.
  142. ^ Hamilton, Tyler (15 January 2008). "Ontario to approve Great Lakes wind power". The Star. Toronto. Retrieved 2 May 2008.
  143. ^ "Naikun Wind Development, Inc". Retrieved 21 May 2008.
  144. ^ "MOU Signed for First Ever Offshore Wind Power Project in India". www.pib.nic.in. Press Information Bureau, Government of India. 1 October 2014. Retrieved 30 April 2015.
  145. ^ R. Srikanth; Sangeetha Kandavel (29 January 2015). "Tapping the offshore wind". The Hindu. Retrieved 30 April 2015.