Wind Energy: Advantages, Disadvantages and Solutions
Harnessing the power of the wind is nothing new. For centuries, it has powered sailing ships, provided energy for windmills and pumped water. Nowadays, with the help of turbines, wind provides us with electricity.
Introduction
I am proud to be a member of the LM Wind Power Group in their blade manufacturing division. Within 30 years of operations, LM Wind Power has produced around 150,000 blades. As such, wind energy is an important subject for me. As an energy source that is renewable and more environmentally friendly than traditional electricity generating technologies, I consider wind energy to be a viable alternative in certain cases. For many uses, wind power is not feasible as a complete replacement to other sources of energy. However, there are specific cases where the wind can provide one of the best solutions for electricity. A solution that is environmentally friendly, cost effective and sustainable. This report will examine cases where wind energy is an advantage, while indentifying some disadvantages in these cases and solutions to overcome these.
Wind Power Technology
Harnessing the power of the wind is nothing new. For centuries, it has powered sailing ships, provided energy for mills (windmills) and pumped water. New technologies developed as a result of new and more efficient energy sources such as coal, fuel oil and gas, replaced the use of wind as a primary source of power. Following World War II, the drop in energy prices further reduced the popularity of wind energy in the United States (Feldman and Hyman 125). In recent decades the volatility of energy prices and growing demand for alternate and renewable energy sources has grown considerably. Dixon and Gorecki report that although wind power provides around 1% of electricity in the U.S. today, upwards of 50% is theoretically possible (30). In the United States, General Electric forecasts that through the rest of this decade, half of all new installed energy generating capacity will be based on wind power. This implies that electricity generated by the wind will increase from 1% to 15%. From a carbon footprint perspective, carbon dioxide emissions will be reduced by 25% (31). Contributing to the growth in power produced by the wind has been the improving efficiencies in the technology used to harness it. The first step in converting wind to usable energy is the use of a windmill. Today, a windmill is called a wind turbine. This turbine converts the kinetic wind energy into electricity. Based on a rotor driven by aerodynamically designed rotor blades placed atop a tower, modern turbines are highly efficient generators. Typically designed with three blades, these modern rotor systems are flexible to allow for static and dynamic bending up to maximum wind speeds of 25 meters per second. Beyond these wind speeds the rotor is brought to stop with the rotor blades oriented at right angles to the wind (Brøndsted, Lilholt, and Lystrup 506-508).
Advantages and Disadvantages of Wind Energy in General
Regardless of the use, wind power has significant advantages over other energy sources. Once built a wind turbine can last for at least 20 years (Dixon, Gorecki. 32). Therefore, once built their carbon footprint is essentially nonexistent. Wind is free to use and in the right geographic location is abundant. In areas where a wind turbine--especially those comprising a wind farm—are most efficiently located are in areas of low population or use. The footprint of a wind turbine is relatively small, typically requiring no more than a quarter of an acre each. Wind turbines can be built to different scales, thereby suiting the needs of utilities, companies and individuals alike. Finally, the use of wind power off the grid makes it suitable for remote, as well as underdeveloped areas of population.
There are several disadvantages to the use of wind as an energy source and with the turbines which harvest that energy. According to Dixon and Gorecki, these include the range of peaks and troughs of wind speed over time, as even in the windiest locales the wind is not constant. Additionally, those turbines installed to deliver electricity to the power grid are commonly located in remote locations where significant loss in energy yield occur over the distance of the required cables (33). Although wind energy enjoys significant support over other energy sources, especially when compared to fossil fuel and nuclear sources, it suffers at the local level. This has become known as NIMBYism (not in my back yard) (Devine-Wright 126).
Cases for Wind Energy Solutions
Wind turbines come in different sizes depending on their intended use. The largest are used in wind farms that are composed of arrays of turbines installed in bodies of water or large open areas of unused or agricultural land. These farms are highly efficient ways to deploy rotors as they are centrally installed, managed and linked to the national power grid. Each of these large sized turbines, with blades around 65 meters long, is capable of producing 6 megawatts (Dixon, Gorecki. 32). With tens or hundreds of these in a wind farm they can add significant power to a nation's supply. Where wind farms are the largest implementation of this technology, a second case for wind power is as installation for an independent power producer (IPP). As the name implies this is an installation of one or more wind turbines for a producer of electricity separate from the local utility. Finally, we look at the case of wind turbines used for power generation for private use off the grid.
Wind Farms
Located in sparsely populated areas, or even offshore, wind farms provide a cost effective solution for adding wind energy to national grids. Advantages include economies of scale; components for wind turbines are delivered and constructed in one location, transmission lines carrying the power are run to one location and the maintenance and operations staff and equipment conduct their work in one location. Another advantage is the selection of geographic location in areas with minimal visual impact and in areas where there is sufficient and abundant wind to capture. Therefore, the disadvantages of peaks and troughs are overcome in part by location and in part by delivery to the grid without need for storage in batteries. An additional advantage of location is that wind farms can be located in areas where there is limited population who use the area as their back yard. However, the disadvantage is that these locations are far from where the power is consumed. Transporting the power to the cities where it is needed can lead to loss of energy from the cables delivering alternating current (AC) at great distances to substations on the power grid. To overcome this disadvantage, a study by Bresesti et. al., suggests that offshore wind farms greater than 90 km from shore would benefit from using high voltage direct current (DC) (43). Another disadvantage of wind farms is their potential effect on bird life. Several environmental impact studies have been conducted without conclusive results. However, as recommended in a study by Drewitt and Langston: "Developers should avoid, wherever possible, concentrations of vulnerable bird species." (40). This and other studies are having an impact on where wind farms are being placed in the future. Indeed, by technology allowing wind farms to be placed further out to sea through better transmission using DC both the disadvantages of peaks and trough and risk to bird colonies are at least partially resolved.
Independent Power Producers
Where wind farms are measured in hundreds of turbines, IPPs have only a few turbines. Also known as Non-utility generators (NUGs), their occurrence in the use of wind power include cooperatives, private companies or individuals. The biggest disadvantage specific to IPPs and wind energy is their size. Where utilities and governments building wind farms have not only economies of scale, they are not impacted by volatilities the same way for-profit IPSs would be. According to Feldman and Hyman, wind power has benefited from government subsides both direct and indirect. These have included mandates by many states in the U.S. for electric companies to purchase a defined percentage of their energy from renewable resources. If these subsidies where to be removed, the IPPs operating for profit would be at significant risk (127). Where wind powered IPPs operate to service a remote community or exist where no other option for power generation is viable the advantages of wind turbines are clear.
Private use
Already in use on farms and other remote dwellings, the potential for generating electricity off the grid for personal use is growing. There are manufacturers producing small turbines that can produce enough power (1000 to 2000 kw) to power an average household. However, there are only certain cases where the use of private power generation using wind energy would be advantageous. These cases include having enough wind, getting planning permission and not having neighbors who would complain too much. Clearly the best use of private wind power would be in locations where the priority is for environmental energy sources are preferred. Additionally, remote locations where there is no access to utility provided electricity, but where wind is common would be a viable situation.
Conclusion
Wind power is gaining popularity throughout the world. While it only accounts for about 1% of power generated in the U.S., other countries are already reaching as high as almost 20%. While the UK has 2%, Ireland and Germany consume 6% of their electricity from wind power. However, Spain uses 9% and Denmark leads all countries in wind power consumption as 19% of their energy consumption comes from wind power (Dixon and Gorecki 30).
Although there are disadvantages to using wind power for electricity generation, there are many areas where it is beneficial as an environmentally friendly source of renewable energy. In specific cases, the disadvantages can be circumvented and still the use of wind energy proves to be advantageous. Perhaps one of the biggest potentials of wind power is energy security. Although we have witnessed in recent years an increase in conventional energy costs due to environmental, political and economic problems, we have not yet seen the need to be completely energy independent. However, it is important to continue investing in alternate sources of energy such as wind power to help assure our future security.
Works Cited
Bresesti, Paolo, et al. "HVDC Connection of Offshore Wind Farms to the Transmission System." IEEE Transactions on Energy Conversion. 22.1 (2007): 37-43. aseanenergy.info
Brøndsted, Povl, Hans Lilholt, and Aage Lystrup. "Composite Materials for Wind Power Turbine Blades." Annual Review of Materials Research. 35. ser. 2005. http://
www.upwind.eu.
Devine-Wright, Patrick. "Beyond NIMBYism: Towards an Integrated Framework for Understanding Public Perceptions of Wind Energy." Wind Energy. 2005.8 (2005). September 8, 2004. www.interscience.wiley.com.
Dixon, Patrick, and Johan Gorecki. Sustainagility: How Smart Innovation and Agile Companies Will Help Protect Our Future. London: Kogan Page, 2010.
Drewitt, Allan L., and Langston, Rowena H. W. Assessing the Impacts of Wind Farms on Birds. 148 (2006). March 27 2006. www.gflrpc.org/programareas/wind/TechnicalDocuments/AvianImpactsSocietyforProtectionofBirds.pdf
Feldman, Jeffrey, and Andrew Hyman. Three Paths to Profitable Investing; Using EFTs in Healthcare, Infrastructure, and the Environment to Grow Your Assets. New Jersey: FT Press, 2010. 125-127.
