Archive for the 'Offshore wind farm case studies' Category

Jul 16 2018

BARD Offshore I Wind Farm: A Case Study

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Germany has always been a leader in renewable energy technology. Due to this dedication, they were able to institute what is now the 9th largest offshore wind farm by nameplate capacity, BARD Offshore I. BARD Offshore I is an offshore wind farm developed by Bard Engineering GmbH in the German North Sea which consists of 80 turbines, each with a nameplate capacity of 5 MW. This leads to an overall installed capacity of 400 MW (BARD Offshore 1 Offshore Wind Farm). The site spans an area of 59 km2 about 101 km from the shore, with the turbines placed on grounded tripiles in water that is approximately 40 meters deep (BARD Offshore 1 Offshore Wind Farm).


The project is stated by 4C Offshore to have a cost of 2.9 billion Euros, which is an extrapolated estimate for capital expenditure based on UniCredit’s Summary Note from January of 2012. UniCredit and the European Investment Bank were the two players who were able to finance the endeavor and kickstart the project and, as of March 2018, there are rumors that Ocean Breeze Energy GmbH & Co. is attempting to sell the wind farm for 1 billion Euros. Due to such a heavy initial investment, Hirtenstein notes that after an unexpected restructuring early in the sites history, the asset was transferred to the Italian bank due to financial inadequacies. The farm has been operational since it’s completion in 2013, meaning that 16 years still remain on the original power purchase agreement made with the German government, which could provide the stable cash flows associated with contracted electricity sales (Hirtenstein, 2018). Although many projects are adequately planned financially, it appears as though there is a trend amongst advancing renewable energy technology in particular of project or even business failure due to a lack of funds. Even in a country like Germany, a renewable energy leader, unplanned expenses can easily derail a project.

Energy Impact:

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In terms of the effects of the offshore wind farm on the community, BARD Offshore I is able to power 283,302 houses annually (BARD Offshore 1 Offshore Wind Farm). Note that this statistic may not translate directly across the world as the homes powered annually is directly correlated with the annual consumption per capita, which differs across nations. Additionally, 4C Offshore stated that the farm led to reductions of 572,554 tons of carbon dioxide and 13,315 tons of sulfur dioxide. It would be safe to assume that these statistics are similarly based upon the specific metrics in Germany. Although these statistics are not expected to be exact, it is important to keep in mind that consumer behavior may change as a result of outside influences such as a change in the source of electricity. Such influences may lead an individual to become aware of the importance of renewable energy and energy conservation and thus make the conscious decision to decrease their energy usage.

Environmental Impact:

In terms of environmental conditions, the turbines at BARD Offshore I have many of the same effects as any other wind farm. The construction stage of the project lasted for more than 2 years, leading to decent exposure to marine organisms (BARD Offshore 1 Offshore Wind Farm). As opposed to the classic monopile configuration, each turbine now calls for three steel beams to be pile driven into the ocean floor, increasing overall surface area affected. This stage of the offshore wind project would constitute the largest concern in terms of underwater noise as the pilings would have to be embedded into the sea floor. This process was expected to produce more than the ambient noise level of 105 dB anywhere within a 20 km radius. Based on the environmental impact assessment conducted by Arcadis, the decommissioning phase would present almost identical impacts as the construction phase but at considerably lower intensity.

Once operational, the issue of underwater noise would still exist but to a lesser extent, with variations in marine organism reactions that is not possible to project with accuracy (Environmental Impact Assessment – Offshore North Sea Power Wind Farm, 2011). Collision casualties from bats or sea birds would, similar to any onshore wind farm, be an issue worth exploring, especially given the massive amount of surface area consumed by BARD Offshore I. Even without direct strikes, an offshore wind farm can affect both fish or bird migration patterns and the cumulative impacts between multiple wind farms can expose a synergistic relationship (Vaissiere et al., 2014). Vaissiere et al. inquires about the environmental impact assessment at its core due to the fact that despite impacts on marine organisms, biodiversity offsets haven’t yet taken hold. If carbon offsets are able to compensate for the weaknesses of fossil fuel energy generation, then EIAs should exercise the power to mitigate and make up for the shortcomings of offshore wind energy.



“BARD Offshore 1 Offshore Wind Farm.” 4C Offshore Ltd, 4C Offshore,

“Environmental Impact Assessment – Offshore North Sea Power Wind Farm.” Arcadis, 6 May 2011,

Hirtenstein, Anna. “UniCredit Is Said to Plan $1.2 Billion Sale of German Wind Farm.”, Bloomberg, 8 Mar. 2018,

Vaissiere, Anne-Charlotte, et al. “Biodiversity offsets for offshore wind farm projects: The current situation in Europe.” Marine Policy, Elsevier Ltd, 19 Mar. 2014,

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Jul 16 2018

Blyth Offshore Demonstrator Array 2: A Case Study


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Pictured: Proposed arrays for Blyth Offshore Demonstrator Arrays 2 (operational), 3 &4 (proposed). (Credit: EDF Energy)

While the original, 2 turbine, 4 MW offshore wind installation off the coast of Blyth, UK has been scheduled for incomplete decommissioning as of January, 2017 (4C Offshore, 2018) due to mechanical and cable failures, the Blyth Offshore Demonstrator Project – Array 2, a 41.5 MW installation is officially operational as of June, 2018 (4C Offshore, 2018). The Blyth Offshore Demonstrator is owned by EDF Energies Nouvelles, a subsidiary of EDF Group, and is being constructed by EDF Energy Renewables, a 50:50 joint venture between EDF Energies Nouvelles and the UK company, EDF Energy. The installation consists of 5 MHI Vestas V164 8.0 MW turbines. These incorporate a power mode uprating to 8.3MW – the largest currently available (EDF, 2017). The installation is located 6.4 kilometers off the Blyth, UK shore. The water depth at the installation site is 29-42 meters. The cost of the project was about 145 million pounds or 192 million USD, approximately 36% of which was spent in the UK. The 5 turbine system produces enough energy for 34,000 homes and save approximately 58,000 tons of carbon dioxide emissions each year. The project incorporates a host of innovations in the foundation process and the use of a 66 kV cable, the details of which will be discussed later.

History and Recent Developments:

Following approval and lease acquisition from The Crown Estate by EDF Energy Renewables in 2015, permitting, consent acquisition, site investigation, procurement, and seabed preparation, all five turbine foundations were fully installed as of August 18th, 2017 (4C Offshore, 2018). Following turbine and cable installation over the course of September through November the installation was producing power as of November 20th, 2017 (4C Offshore, 2018). A minor issue with a section of the cable array prompted the replacement of that section of cable on December 7th, 2017. The installation was fully commissioned on January 9th, 2018 and the Blyth wind farm was inaugurated by EDF Energy Renewables at the opening ceremony on June 22nd, 2018. The Blyth Offshore Demonstrator Project – Array 2 is expected to be decommissioned at the end of its 22-25-year design life in accordance with the terms of its Crown Estate lease (4C Offshore, 2018).

Innovative “Float and Submerge” Technique:

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(Credit: BAM Nuttall, 2017)

As aforementioned, this project was the first to utilize a new foundation installation technique. This process, a gravity based foundation (GBF) design method, involves floating the foundations into position at sea and submerging them onto the seabed to provide the support structures that act as the foundations for the installation of the turbine towers. (EDF, 2017) It is the first time this method has been used for offshore wind turbine installation, having previously been used for offshore oil and gas extraction. Current methods of offshore wind deployment consist of the monopile method, in which a monopile is sunk 30-60 feet into the seabed, the gravity foundation method which utilizes a large concrete or steel base, and the tripod method, in which the piles are driven, again, deep into the seabed (Whitlock, 2017). The float and submerge method has the advantage of enabling the gravity base foundations to be towed out to sea by tugboats, rather than utilizing more expensive heavy-lift crane vessels.  The design also reduces the need to use expensive marine equipment for the installation on the sea bed itself does not utilize a pile driving technique which has been proven a major source of auditory pollution in the nearshore and offshore marine environments (Peng et al., 2015).

Cable Innovation: From 33kV to 66 kV:

The project is also the first of its kind to utilize a new kind of export cable technology. From the Developers Brochure: “Blyth Offshore Demonstrator will be the first offshore wind project to use 66kV rated inter array and export cables to connect the turbines to the new onshore substation on part of the site of the former Blyth power station” (2017). In, “The Use of 66kV technology for Offshore Wind Demonstration sites”, Neumann et al. (2014) addressed the feasibility of developing a system implementing 66kV at the Blyth Offshore Demonstration site, citing several potential benefits. These include “the potential to reduce the amount of submarine cabling required, reduced losses in the connection at 66kV versus 33kV, and the potential to eliminate offshore substations in some cases.”

While intra-array 66 kV cable systems were not approved at the time this paper was written, their analysis of these benefits of the 66kV system is supported by other studies from organizations such as the Carbon Trust’s Offshore Wind Accelerator (OWA) which also showed that in addition to the benefits discussed by Neumann et al., 66kV systems “increase the power density through the cables and hence result in more cost effective cable systems” and that transmitting power back to shore at this higher voltage is also “a more efficient and cost effective option”. (Ferguson et al., 2012).

Video: 66kV cable being simultaneously laid and buried. (Credit: Boskalis Subsea cables & Flexibles, 2018)

Environmental Impact Assessment and Monitoring:

As with any offshore wind installation, rigorous environmental impact assessments were conducted before and during commission of the project. According to the EDF Energy, “The Environmental Impact Assessment (EIA) carried out by the former project owner NAREC included extensive site studies on marine ecology, birdlife, landscapes and seascape, commercial fishing and other environmental matters” (2017). According to Natural Power, a consulting firm hired by EDF Energy to conduct environmental impact surveys, “Natural Power has undertaken benthic and fish monitoring to update baseline knowledge of the environment before construction.” The firm also notes in the 2017 case study of the project, that “since consent was awarded, a Marine Conservation Zone has been designated (in part) for benthic habitats and this area includes the near shore section of the export cable route.”

Furthermore, in 2015, EDF Energy Renewables commissioned Newcastle University to “install C-pod devices at the site to monitor the vocalizations of some marine mammal groups” (EDF, 2017). These devices informed developers of what mammals are doing in the area and also provided information on the relative occurrence and distribution of porpoises and dolphins for monitoring. The devices remained at the site until 2018 (EDF, 2017). While sufficient, some recent studies suggest further monitoring could be useful in the determination of chronic environmental impacts on marine mammal populations specifically (Mann and Teilmann, 2013).


The project is a 50:50 joint venture funded by both EDF Energies Nouvelles and EDF Energy (4C Offshore, 2018). The developers pledged approximately 36 percent of the construction cost were to be spent in the UK and a Blyth Offshore Demonstrator Community Fund was established to support local groups and charitable activities in the area. The project also played a role in testing and proving new and emerging offshore installation methods and technologies, encouraging investment in the sector (EDF, 2017).


  1. Ferguson, et al. “Benefits in moving the inter-array voltage from 33 kV to 66 kV AC for large offshore wind farms” EWEA 2012
  2. P. Neumann, M. J. Mulroy and C. Ebden, “The use of 66kV technology for offshore wind demonstration sites,” 3rd Renewable Power Generation Conference (RPG 2014), Naples, 2014, pp. 1-6.
  3. EDF Energy Renewables. (2017). Blyth Offshore Demonstrator Wind Farm [Brochure]. London.
  4. Events on Blyth Offshore Demonstrator Project – Array 2. (n.d.). Retrieved July 16, 2018, from—array-2-uk70.html
  5. Mann, J.; Teilmann, J. (2013). Environmental Impact of Wind Energy. Environmental Research Letters, 8, 1-4
  6. Natural, P. (2017). Natural Power – Blyth Offshore Demonstrator Project Case Study(Rep.). Natural Power.
  7. Peng, C., Zhao, X., & Liu, G. (2015). Noise in the Sea and Its Impacts on Marine Organisms. International Journal of Environmental Research and Public Health, 12(10), 12304–12323.
  8. Whitlock, R. (2017, July 13). Wind – New ?Float and Submerge? method utilised on UK offshore wind farm. Retrieved from–method-20170713/

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Jul 16 2018

A Case Study: Kamisu Nearshore Wind Farm

Japan has long relied on fossil fuels and nuclear power as their primary energy sources but have recently been moving more towards renewables. Japan has a significant amount of marine renewable energy potential considering their location as an island in the Pacific Ocean. The Kamisu wind farm was the first Japanese offshore wind farm and it paved the way for other offshore wind projects.

The Kamisu nearshore wind farm is located roughly 50 meters off the southernmost edge of the city of Kamisu, Japan in the Kashima-Nada Sea. It consists of seven turbines, each producing 2 MW, to total an energy capacity of 14 MW (4C Offshore, 2010). A second wind farm made of 8 wind turbines was built up in the same area only three years later due to the success of the first set of turbines. The same model of turbines was used, allowing for an additional 16 MW to be produced at the Kamisu wind farm (4C Offshore, 2013).

Copyright Wind Power Ibaraki

The local government chose a private, regional renewable energy company called Wind Power Ibaraki Ltd. to develop and maintain operation of the wind farm (JWPA, 2017). No information was found on the preliminary decisions regarding the project or finances, since many of the documents are in Japanese. However, according to METI estimates, development of a project of this size in 2013 would cost nearly 16 billion Japanese yen, with significant funding coming from the government (Carbon Trust, 2014).

An EIA (Environmental Impact Assessment) Law was established in Japan in 1999 but did not cover wind energy projects until 2011 (Carbon Trust, 2014). The first phase of the Kamisu wind farm became operational in 2010 and the second phase was already in motion, therefore the Kamisu wind farm was not required to undergo an EIA.

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The major environmental impacts of offshore wind are generally noise pollution and EMFs (electro-magnetic fields) that may disturb marine organism behavior. Due to the close proximity to land, the impact of EMFs on marine life is reduced as compared to marine energy projects located further away. The Kashima port is also located nearby, with shipping vessels contributing to noise pollution. This fact may potentially cover up the operational noise of the wind turbines or just increase the overall noise pollution in the sea. No studies have been done to investigate this.

The turbines use a monopole foundation driven into the seabed to keep them steady, which is especially necessary since Japan is prone to tsunamis. The turbines are in four meter deep water, slightly shallower than most offshore wind turbines. They have 60 meter tall towers, with 40 meter blades, totaling a 100 meter height- a pretty standard turbine size (4C Offshore, 2010, 2013). Wind speeds in the located area are about 7 meters per second, suitable for 0-10 MW turbines (JWPA, 2017). No documentation was found on the installation process for this project.

© Takeshi Ishihara
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The first seven turbines became operational in 2010, and the wind farm was extended in 2013. The project provides electricity to about 21,000 homes annually and has reduced carbon dioxide emissions by almost 43,000 tons each year (4C Offshore, 2010, 2013). While these numbers represent only a tiny fraction of Japan’s population and the world’s carbon emissions, it is still inspiring to see this progress.

The wind farm survived the 2011 tsunami that led to the Fukushima nuclear power accident. No damage was found on the turbines but they were forced to stop generating power due to issues connecting to the grid. They became fully operational again in 3 days (JFS, 2011). After this incident, the Japanese public’s trust of nuclear power became shaky and the government has reduced its use of this energy source. Hopefully, this will motivate the public to push for renewable energy projects.

The government has invested in many new offshore wind projects since the incident and in 2012, proposed construction of a larger wind farm offshore of Kamisu. This wind farm would consist of twenty 5 MW turbines, that would produce a total of 100 MW (JFS, 2012). No recent news has been reported, suggesting that the project is still undergoing assessment and licensing but wind power companies have already been chosen to develop the project and investors have agreed to take part (ORIX, 2015). This is an exciting advancement in the field of renewable energy that provides hope for cleaner and safer energy sources.



“Kamisu Nearshore Wind Farm – Phase 1 Offshore Wind Farm.” 4C Offshore Ltd, 4C Offshore Ltd, July 2010,—phase-1-japan-jp05.html.

“Kamisu Nearshore Wind Farm – Phase 2 Offshore Wind Farm.” 4C Offshore Ltd, 4C Offshore Ltd, Mar. 2013,—phase-2-japan-jp17.html.

“Offshore Wind Power Development in Japan.” Japan Wind Power Association. 2017.

“Major Japanese Wind Power Project Offshore from Port of Kashima Announced. JFS Japan for Sustainability.” JFS – Japan for Sustainability, Japan for Sustainability, Dec. 2012,

Appraisal of the Offshore Wind Industry in Japan . Carbon Trust, British Embassy Tokyo, 2014,

“Offshore Wind Farm Withstands Great East Japan Earthquake and Tsunami. JFS Japan for Sustainability.” JFS – Japan for Sustainability, JFS – Japan for Sustainability, July 2011,

“ORIX Participates in the Development of Kashima Port Large-Scale Offshore Wind Farm.” ORIX | News Releases | 2015 | ORIX Participates in the Development of Kashima Port Large-Scale Offshore Wind Farm, ORIX, 2015,

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