Chem321:Offshore wind farms

Offshore Wind Farms: A Safer & Cleaner Means to Generate Electricity

Wind energy is one of the most common ways of generating electricity other than fossil fuels in many countries today. It is also one of the cleanest and safest means of generating electricity. There are many uses for wind power besides electricity generation, such as mechanical power via windmills, sails to propel ships, and windpumps for water pumping or drainage. Wind turbines are used to generate electricity via the wind, and farms that contain many wind turbines are called wind farms. In the North Country there are wind farms near Chateaugay (which is east of Malone), a few miles south of Ellenburg (which is north of Plattsburgh), and just north of Lowville.

With the effects of global warming and climate change on our planet becoming more clear with each passing year, and with the quickly dwindling amounts of fossil fuels left on Earth, it is imperative that we find cleaner and more renewable resources to power our homes. This is why wind power is so important, and why more and more countries are jumping on board with the idea. Though many wind farms are located on land, the idea of offshore wind farming is growing more popular, especially in Europe. The current interest in wind power began in California, however, in the 1980s after the energy crises of the 1970s. Wind development was given a large boost in the 1990s with improvements in technology resulting in an increase in turbine reliability and lower costs of production. Because of the unreliability of federal tax incentives, the wind industry went through several cycles of booms and busts despite growing substantially. It took until 2006 for a period of uninterrupted federal support for wind power to begin. In Europe the wind industry has had more long-term and consistent support. Countries there are thus currently able to meet more of their electricity demands via wind power using much less land area and resource potential.

The first offshore wind farm was installed in Denmark in 1991. Europe is currently the world leader in offshore wind farming, as there are none in the United States as of 2012. There are plans in the works, however, to build offshore wind farms in the United States, particularly along the East Coast, Pacific Coast, and the Great Lakes.

Pros and Cons of Fossil Fuels

Fossil fuels are defined as fuels formed from the fossilized remains of dead plants by exposure to intense heat and pressure. The most common fossil fuels found on Earth are coal, petroleum (crude oil), and natural gas. There are many advantages to using fossil fuels as a means to generate electricity. Fossil fuels are more easily available as compared to other fuels, and the extracting and refining processes are not time consuming. They are considered to be “high-efficiency fuels” because their combustion can generate a large amount of usable energy. Transportation is not an issue for fossil fuels. Coal is easy enough to move around that power stations that use it can be built anywhere. Also, oil and natural gas can be transported across large distances via pipelines, such as in Alaska. Coal is also the most plentiful resource in the world, is cheap, and is a highly reliable source of energy. Also, the task of processing these fossil fuels provides jobs for millions of people all over the world.

However, there are also many disadvantages. Fossil fuels are non-renewable resources, and the depletion of these fossil fuels is taking place at faster and faster rates because of the increasing demand for energy. The production of fossil fuels takes millions of years, and so as the amount of fossil fuels dwindles, we will not be able to renew them nearly fast enough. The extraction of fossil fuels leads to deforestation and the destruction of habitats for countless plants and animals. It can also lead to irreparable damage to marine environments via drilling. The consumption of fossil fuels can result in many other harmful environmental effects, such as releasing greenhouse gases into the atmosphere, precipitation of acid rain, and direct pollution via oil spills. It can also emit hazardous gases that can cause breathing ailments in humans and other animals. Acquisition of fossil fuels can be a difficult task, since they are only found deep beneath the surface. Oil drilling and excavating are very expensive and require long-term research and planning. Finally, when we burn coal, only a third of its fuel energy potential is currently being used when it is burned for power, according to the Department of Energy. These multiple negative effects of fossil fuels outweigh the positive effects, which is why many areas of the world are promoting wind energy as an alternative to fossil fuels.

Technical Information

Depending on their use, wind turbines come in many different sizes and in a few different styles. The most common type is the horizontal axis design, which has the axis of the blades horizontal to the ground. Two or three blades spin upwind of the tower that they sit on. From the outside, these wind turbines consist of three main parts: the tower, the blades, and a box behind the blades called the nacelle. The nacelle is where the main action takes place - in other words, the place where motion is turned into electricity. The blades are attached to an axle that runs into a gearbox, or transmission, which speeds up the rotation from 50 rpm up to 1,800 rpm. Inside the generator spins the faster spinning shaft, which generates AC electricity. Offshore turbines in particular have an additional important part to them that are not needed on land - bases for stability. For water up to 30 meters deep, turbines have a monopile, or single column, base, which is six meters in diameter. For water between 20 and 80 meters deep, there are four types of bases used - gravity base structures, tripod piled structures, tripod suction caisson structures, and conventional steel jacket structures (as used in the oil and gas industry). For deeper water, floating wind turbines are used.

A potential problem with this wind turbine design is that electricity needs to be produced at just the right voltage and frequency in order for it to be compatible with a utility grid, and since the wind speed can vary greatly, the speed of the generator could also vary. This could produce fluctuations in the electricity. One way to get around this problem is to have constant speed turbines. In these turbines, the blades adjust by turning slightly to the side in order to slow down when there are gusts of wind. Another solution is to have variable-speed turbines, where the blades and generator change speeds along with the wind. Any fluctuations in electrical output would be fixed by using sophisticated power controls. Variable-speed turbines have an advantage over constant-speed turbines in that they are able to operate in a wider range of wind speeds. This is important since every wind turbine has a lower and upper limit to the wind speeds they can handle. If the wind is too slow there is not enough power to turn the blades, and if the wind is too fast, the equipment runs the risk of damage.

Why Offshore?

In a typical offshore wind farm, there are around 50 to 70 turbines, made by either the Siemens or Vesta companies. These farms normally have a nameplate capacity, or sustained output, of approximately 200 megawatts per day. The locations of the major offshore wind farms in the world are in Europe - specifically in Denmark, Germany, Belgium, the Netherlands, and the United Kingdom. The largest offshore wind farm in the world is the Walney wind farm. It is located in the Irish Sea off the coast of England. Completing construction in March 2012, it has a total of 102 wind turbines and has a nameplate capacity of 367 MW. It covers an area of about 73 square kilometers and is located in waters of 19 to 23 meters deep.

There are many benefits to offshore wind farming. Just one offshore wind farm can produce enough energy to power about 125,000 homes every year. This energy is clean and renewable, and is completely free - no more fuel adjustment charges on people’s electric bills. With just one wind farm, replacing fossil fuel-generated power with wind power can help reduce the amount of carbon dioxide emissions per year decrease by 1.3 billion pounds, thereby reducing greenhouse gases and air pollution. It also reduces the need to import 17 million barrels of oil every year. Offshore wind farms are also excellent at creating jobs for skilled workers. Jobs associated with offshore wind farms include fabrication of the turbine foundations, installation of these foundations and the turbines themselves, laying down undersea cables, and various maintenance and operations positions. Each utility-scale offshore wind farm is able to employ hundreds of workers, and the manufacturing of the products associated with these wind farms will require hundreds more. By 2030 it is estimated that in Europe there will be more than 200,000 workers employed in the offshore wind sector. Also, the energy consumed to manufacture and transport the materials used to build these offshore wind farms is equal to the new energy that is produced by these farms during a period of a few months.

There are also beneficial advantages to offshore wind farms as opposed to wind farms on land. Wind is much stronger off the coasts than on land due to the water having less surface roughness than the land. These offshore breezes are especially strong during the afternoons, which is when people are using the most electricity. They can also eliminate the need to build new overland transmission lines, especially in heavily populated areas along the coasts. The biggest advantage offshore wind turbines have, however, is that they are much less obtrusive than land-based wind turbines. The size of the turbines and the amount of noise they make is mitigated by their distance from shore.

As beneficial as offshore wind farms can be, they also have attracted controversy, especially in the United States. The Cape Wind project is a proposed wind farm that would be located in Nantucket Sound, off Cape Cod in Massachusetts. It is a $2.5 billion initiative that would have 130 wind turbines and have a capacity of 454 MW of renewable electricity, making it even larger than Walney. Since the project was proposed in 2001, however, a group called the Alliance to Protect Nantucket Sound was created specifically to oppose it. This group believes in green and sustainable energy, but not in the proposed location. The Alliance believes that the wind farm would threaten and disrupt ship navigation and air traffic control, destroy the local fishing industry, and be a source of visual and sound pollution that could harm birds and aquatic life. Prominent politicians such as the late Ted Kennedy, Mass. senator John Kerry, and former Mass. governor Mitt Romney.

It is clear that Europe has the right idea when it comes to renewable energy, and with the number of offshore (and land-based) wind farms located there, the continent is well on its way to gradually phasing out power based on fossil fuels. Hopefully it is only a matter of time before the same thing happens in the United States.

Works Cited

Blomberg, Lindsey. "Cape Wind Controversy Continues." EMagazine.com. EMagazine.com, 3 Jan. 2012. Web. 08 Aug. 2012. <http://www.emagazine.com/daily-news/cape-wind-controversy-continues/>.

Gipe, Paul. Wind Power: Renewable Energy for Home, Farm, and Business. White River Junction, VT: Chelsea Green, 2004. Print.

Muyeen, S. M., Junji Tamura, and Toshiaki Murata. Stability Augmentation of a Grid-connected Wind Farm. London: Springer, 2009. Electronic.

"Offshore Wind Energy." Offshore Wind Energy. Bureau of Ocean Energy Management, n.d. Web. 08 Aug. 2012. <http://ocsenergy.anl.gov/guide/wind/index.cfm>.

"What Are the Pros and Cons of Fossil Fuels?" WikiAnswers. Answers, n.d. Web. 08 Aug. 2012. <http://wiki.answers.com/Q/What_are_the_pros_and_cons_of_fossil_fuels>.