Wind Turbines: Designs and Costs - Research Paper Example

Wind Turbines: Designs and Costs Background Wind energy has been harvested by man for over two millennia, theearliest use being in sailing, then pumping water and grinding flour. However, it was not until the 1930s when Leroy Ratzlaff and his family built a small wind turbine for harvesting the high winds that blew across the ridge at South Dakota in Hyde County where they lived. The first electricity generating wind turbines would have to wait until the 1980s (Kjaer). The modern wind energy was born in 1982 when European manufacturers of agricultural machinery managed to install about 25-30 turbines in California. By the following year, 350 turbines had been installed capable of a total capacity of 20 MW (Kjaer). Today, wind energy is the fastest-growing electricity source in the world and production capacity per turbine generator has grown from the 1982 55kw to the 5,000kw (Kjaer). Turbine technology has also enabled wind energy production at varying heights both at higher and at low to medium heights. In addition to harvesting winds at broader heights, the trend of wind turbines has also been marked with increasing sizes. This is due to the fact that larger wind turbines capture more power and is more economical. Modern wind turbines further have more flexible structures to operate in uncertain environments. Improved turbine design requires proper wind inflow characterization. Laks, Pao, and Wright note that rapid change in direction, concentrated wind gusts, or passage of energetic atmospheric structure creates critical loads on individual wind turbines (n.pg). Such extreme events decrease turbine lifetimes; they cause components failure and can threaten catastrophic machine failure. Future designs of turbines are focusing on understanding the complexity of wind inflow into the turbines so as to design load mitigating controls that protect the turbine from such complex atmospheric phenomenon. Wind turbines design and cost of wind energy With the current advances in Science and Engineering, the capacity of wind power is expected to increase as the cost of this power lower due to more efficient designs. The investment in wind power is expected to have grown to $ 60 billion in 2016 from the $ 18 billion in 2006 (Pao and Pao, Kathryn and Johnson). The period from 1980 to 2003 was marked by significant improvement of wind turbines productivity and their capital costs which in turn was associated with reduction in the Levelized Cost of Energy (LCOE). Wiser and Bolinger note that the capital cost in the United States fell by approximately 65% from the early 1980s to attain the lowest level at around 2001 to 2004 (qtd. in Lantz, Wiser and Hand 3). Denmark also had a similar trend with a capital cost falling by over 55% within the same period (Nielsen et al, qtd. in Lantz, Wiser, and Hand 3). Within this time period, there was an increase in installed wind power globally from negligible amounts to 40, 000 MW. This was enabled by a technological development where larger blades could be produced at lower costs (Lantz, Wiser, and Hand 4). During this period, the LCOE dropped from $150/MWh to around $50/MWh (Lantz, Wiser, and Hand 14). The capital costs were observed to rise in the period 2004-2009 whereas the turbine performances increase; the result was a moderate increase in the LCOE. The period 2009-2013 has seen the turbine and projects capital costs decrease significantly, and with continual improvements in turbine designs Wiser predicts the industry to attain an apparent historic low in wind LCOE (qtd. in Lantz, Wiser and Hand 15). The future of wind turbines The future turbines are expected to have various improvements in design aimed at reducing cost and increasing power production output. Cohen et al. estimate that turbines with taller towers could increase energy output by 11% (quoted in Lantz, Wiser, and Hand 24). However, increasing tower heights may lead to increased cost but unless new designs are invented. U.S. DOE 2008 says that future designs may incorporate advanced control systems and an integrated system to reduce tower loading cost. In future turbines will either have new structural designs, or hybrid concrete and steel towers. A hybrid steel and concrete tower could result into a 40%-50% reduction in cost materials (Cena and Simonot qtd. in Lantz, Wiser, and Hand 24). Future turbines designs may also be focused on easing crane height requirement, for example, having self-erecting or partial self-erecting towers. This together with on-site manufacturing facilities will reduce logistics constraints and costs. As countries aim to increase wind energy production, future designs of turbines will aim at larger rotor diameters. Cohen et al notes that larger blades may increase energy output by 10% TO 30%. Larger blades, however, could increase costs, but this may be mitigated by new designs that reduce blades weight and loads. Reducing weights might be achieved with designs with the ability to control different sections on the blade or shedding of loads by twisting (Ashwill quoted in Latz, Wiser, and Hand 24). Future turbines may also have sensing capacities that enable the rotor adapt to changes in wind conditions or turbulence at different parts on the rotor disk (van Kuik 2009 qtd. in Lantz, Wiser and Hand 24). In the future, it is also expected that drive-train is going to achieve reduced weights through improved controls, which will increase performance and reduce costs. In future turbines are expected to use condition monitoring more broadly and have a more refined operational strategy to reduce costs of operations and replacements. Upwind, notes that in future turbines will have enhanced frequency and voltage output, and a broader operative range (qtd. in Latz, Wiser, and Hand 23). These improvements of power electronics could reduce costs further while increasing output. Environmental effects of wind turbines As compared to any other source of electricity, wind energy has the least adverse environmental impacts. Wind energy production results in no pollution or wastes to dispose and can actually be used as the energy source alternative to mitigate pollution from energy sources like coal (Energy Centre of Wisconsin (ECW). The use of wind energy, therefore, lowers the release of greenhouse gases such as carbon dioxide and sulfur dioxide both eminent from the use of coal. However, wind turbines are not entirely benign they create some other types of impacts. One may impact in history has been fatalities to birds and bats (National Research Council 14). Most birds and bat fatalities occur mostly from impact with the rotating rotors; this was a major effect in California in the 90s. However, this problem was a major concern only in the 80 and 90s with modern turbines killing only one to two birds on average (Renewable Energy Research Laboratory (RERL) 2). Modern designs of turbines are larger, and the rotating speeds lower such that birds can maneuver around. Turbines also contribute to noise pollution emanating from the rotating rotors especially at summers when windows are open and at night. Modern turbines have fewer impacts on noise with slower rotation of blades. Past wind turbines have also been recorded to cause interference of communication signals and lead to ‘ghosting’ on TV screens. Today, the metal blades are being replaced with fiberglass composite, which does not interfere with broadcast signal (RERL 3). Today the primary environmental impact of wind turbines is visual. Wind turbines need to be exposed, and therefore, most often are in prominent locations yet here are people who hate the sight of the turbines (RERL 3). Conclusion Wind energy is rapidly growing and becoming the most popular source of renewable energy because of its very little environmental impacts. Since the 1980s, there have been unprecedented improvements in designs of wind turbines and more innovations are anticipated in the future. The designs innovation has led to increase in energy outputs while costs have fallen. This trend is expected to be carried into the future. Works Cited Energy Centre of Wisconsin (ECW). Wind power and the environment. Web. 16 Nov. 2013 Energy Research Laboratory (RERL). Wind Power: Impacts and Issue. Web. 16 Nov. 2013 Kjaer, Christian. History: Powering Change since 1982. Web. 16 Nov 2013 Laks, Jason, Lucy Pao, and Wright, Allan. Control of Wind Turbines: Past, Present, and Future. University of Colorado, 2009. Web. 16 Nov 2013 Lantz, Eric, Wiser, Ryan and Hand, Maureen. IEA Wind Task 26: The Past and Future Cost of Wind Energy. Denver West Parkway Golden, Colorado: National Renewable Energy Laboratory, 2013. Print National Research Council. Prepublication Copy. Environmental Impacts of Wind-Energy Projects. Washington, D: The National Academies Press, 2007. Print Pao, Lucy, and Johnson Kathryn. A Tutorial on the Dynamics and Control of Wind Turbines and Wind Farms. Web. 16 Nov 2013 Read More