By Kari Andresen

Abstract

Offshore wind energy is a recently developing industry that aims to reduce carbon dioxide emissions and other harmful side effects of obtaining energy from nonrenewable sources. The industry is mainly situated in European countries, especially Denmark and the United Kingdom, which have the largest wind farms and produce the most offshore wind energy in the world. The London Array in the Thames Estuary is the biggest wind farm in the world. Off the western coast of Denmark in the North Sea is Horns Rev 2, one of the top energy generating wind farms worldwide. The first wind farm in the United States is currently being planned, and will be built in Nantucket Bay. There have been past efforts to create a wind farm near New York City, similar to our proposal, but they have not been approved.

Many offshore wind farms have been created since the first one, Vindeby, in 1991 off the coast of Lolland, Denmark, though none have been constructed in the United States. Clean alternative energy from oceanic winds is a European-dominated industry, but in recent years, some offshore wind farms have been established in China and Japan. The countries with the most successful offshore wind farms are the United Kingdom and Denmark.

The most extensive single wind farm in the world is the London Array at 175 wind turbines spanning over 100 square kilometers in the Thames Estuary (11). Its rated power capacity is 630 MW, which is enough to power 500,000 houses in southeast England (7). For the amount of energy that the London Array produces, if more traditional sources were used instead, an estimated 925,000 metric tons of carbon dioxide would have been released into the atmosphere, whereas the London Array has no emissions (11). The enterprise began in 2001 following studies about the suitability of putting wind turbines in the outer Thames Estuary where there are high wind speeds and the water is not too deep. For the next six years, London Array Ltd. obtained all the required permits and licenses and the lease for the farm area and connections to the shore. In 2009, construction finally started. The onshore substation was built in Cleve Hill, where the wind energy would be connected to the national grid. The wind turbines used were Siemens 3.6MW-120m rotor turbines, and they were installed to face the dominant wind direction for higher energy production (10). In the summer of 2011, two offshore substations were constructed, and soon after the array cables were connected and the export cables were secured from the offshore substations to the onshore substation at Cleve Hill and buried under the seabed. The turbines underwent extensive testing for performance before they were finally commissioned in 2013. The London Array wind farm is built to operate between wind speeds of 4 m/s to 25 m/s everyday for 20 years (5). If the wind speed exceeds 25 m/s, it will automatically shut down. Now that it is in operation, the turbines and the environment are inspected regularly. If this first stage continues to yield positive results, then the second stage for additional wind turbines will commence.

Denmark’s Horns Rev 2 wind farm is one of the highest producers of total offshore wind energy since it was first commissioned by DONG Energy. Environmental evaluations for the wind farm location, as well as permit applications, occurred in 2005, and it was fully approved in 2007. Its construction began in 2008 in the North Sea, where 91 wind turbines would be erected by the next year, providing for a rated capacity of 209 MW to its substation is Esbjerg, Denmark (9). The wind turbines are also made by Siemens, using the 2.3MW-93m rotor model (3). Horns Rev 2 is a greater distance from land than any other wind farm at 31.7 kilometers (1). To speedily alleviate problems and facilitate communication, an IP address was given to each individual turbine and fiber optics were included in the cables for remote controlling (3). The array cables connect the turbines in rows with the cables converging on the east side of the array at a transformer platform, which then delivered the current to the onshore substation. Below is a diagram of the array (red trigonal lines), the cables (the pink lines), the transformer platform (the black pin), and the surrounding lighted buoys (yellow stars) (2).

The United States is currently in the process of financing its first wind farm, Cape Wind in Nantucket Sound. It has gotten all required state and national permits and won all court challenges to the project. Cape Wind is scheduled to start construction soon after 2014. It will be composed of 130 Siemens Wind Turbines of the same model as the London Array (3.6 MW) (4). Cape Wind will be able to supply a maximum of 468 MW to Cape Cod and its surrounding islands, Martha’s Vineyard and Nantucket. It is estimated to supply three-fourths of the energy in the region (4). This site at Horseshoe Shoal was approved to contain America’s first offshore wind turbine after much investigation because the high wind speed is ideal with an average of 19.5 mph, while having less harsh waves than in the Atlantic Ocean due to the land surrounding it (12). The demand for power is also very high in the surrounding region.

There have been past proposals for a wind farm near New York City. The most recent proposal was the Long Island-New York City Offshore Wind Project, which is a revival of a previously rejected proposal by the Long Island Power Authority to have a wind farm off the coast of Jones Beach (6). Many Long Islanders had an issue with the first proposal because it would have been visible from the shore, and many real estate businesses felt that the visible wind turbines would decrease the value of the land. The second proposal aims to establish a wind farm more west so that it’s closer to New York City and farther south so that it’s less visible from shore, though it would not be out of sight. This plan has not yet been approved or denied. We believe that this plan may fail due to the same reasons as the first effort—visual pollution. Therefore, in our proposal, we plan to build a wind farm that is even farther south (25 miles away from the coast), so it will receive less opposition from people who reside on the shore. In addition, the wind speed in the area that we propose is higher, which would be able to produce more energy and may make up for the transmission loss caused by the increased distance.

There are currently 64 operating wind farms around the world, and they have all been made in the past 25 years (8). This industry was created and continues to grow because people have realized the necessity of having more reliable energy sources that do not contribute to the global ecological problems that we are beginning to feel the repercussions of today, such as global warming. Using offshore wind energy has decreased countries’ carbon dioxide emissions significantly. If the whole world continues its efforts to create more offshore wind farms and other powerful sources of sustainable energy, we may be able to halt the growing threat of global warming.

References:

1. “About Horns Rev 2: About the Project.” DONG Energy: Horns Rev 2. DONG Energy, n.d. Web. May 2014. <http://www.dongenergy.com/hornsrev2/en/about_horns_rev_2/about_the_project/pages/about_the_project.aspx>.
2. “About Horns Rev 2: Cables.” DONG Energy: Horns Rev 2. DONG Energy, n.d. Web. May 2014. <http://www.dongenergy.com/hornsrev2/en/about_horns_rev_2/about_the_project/pages/cables.aspx>.
3. “About Horns Rev 2: Turbines.” DONG Energy: Horns Rev 2. DONG Energy, n.d. Web. May 2014. <http://www.dongenergy.com/hornsrev2/en/about_horns_rev_2/about_the_project/pages/turbines.aspx>.
4. “Cape Wind Project Overview.” Cape Wind. eCape, 2014. Web. May 2014. <http://www.capewind.org/what/overview>.
5. “Commissioning the Wind Farm.” London Array. E.ON, DONG Energy, Caisse De Dépôt Et Placement Du Québec, and Masdar, n.d. Web. May 2014. <http://www.londonarray.com/the-project/operations-maintenance/>.
6. “Frequently Asked Questions.” Long Island, New York City Offshore Wind Project. Long Island-New York City Offshore Wind Collaborative, n.d. Web. May 2014. <http://www.linycoffshorewind.com/faq.html>.
7. “Harnessing the Power of Offshore Wind.” London Array. E.ON, DONG Energy, Caisse De Dépôt Et Placement Du Québec, and Masdar, n.d. Web. May 2014. <http://www.londonarray.com/>.
8. “Home Page.” Cape Wind | America’s First Offshore Wind Farm. eCape, 2014. Web. May 2014. <http://www.capewind.org/>.
9. “Horns Rev 2.” 4C Offshore. N.p., n.d. Web. May 2014. <http://www.4coffshore.com/windfarms/horns-rev-2-denmark-dk10.html>.
10. “Key Facts: London Array Location.” London Array. E.ON, DONG Energy, Caisse De Dépôt Et Placement Du Québec, and Masdar, n.d. Web. 12 May 2014. <http://www.londonarray.com/the-project/key-facts/location/>.
11. London Array: The World’s Largest Offshore Wind Farm. London: London Array, n.d. LondonArray.com. E.ON, DONG Energy, Caisse De Dépôt Et Placement Du Québec, and Masdar. Web. May 2014. <http://www.londonarray.com/wp-content/uploads/London-Array-Brochure.pdf>. Page 3.
12. “Why Nantucket Sound Is Right for Cape Wind.” Cape Wind. eCape, 2014. Web. 12 May 2014. <http://www.capewind.org/where/location>.