Wind power capacity and production
Worldwide there are now over two hundred thousand wind turbines operating, with a total nameplate capacity of 282,482 MW as of end 2012. [ 44 ] The European Union alone passed some 100,000 MW nameplate capacity in September 2012, [ 45 ] while the United States surpassed 50,000 MW in August 2012 and China passed 50,000 MW the same month. [ 46 ] [ 47 ]
World wind generation capacity more than quadrupled between 2000 and 2006, doubling about every three years. The United States pioneered wind farms and led the world in installed capacity in the 1980s and into the 1990s. In 1997 German installed capacity surpassed the U.S. and led until once again overtaken by the U.S. in 2008. China has been rapidly expanding its wind installations in the late 2000s and passed the U.S. in 2010 to become the world leader.
At the end of 2012, worldwide nameplate capacity of wind-powered generators was 282 gigawatts (GW), growing by 44 GW over the preceding year. [ 44 ] According to the World Wind Energy Association , an industry organization, in 2010 wind power generated 430 TWh or about 2.5% of worldwide electricity usage, [ 48 ] up from 1.5% in 2008 and 0.1% in 1997. [ 49 ] Between 2005 and 2010 the average annual growth in new installations was 27.6 percent. [ 50 ] Wind power market penetration is expected to reach 3.35 percent by 2013 and 8 percent by 2018. [ 50 ] [ 51 ]
Several countries have already achieved relatively high levels of penetration, such as 28% of stationary (grid) electricity production in Denmark (2011), [ 52 ] 19% in Portugal (2011), [ 53 ] 16% in Spain (2011), [ 54 ] 14% in Ireland (2010) [ 55 ] and 8% in Germany (2011). [ 56 ] As of 2011, 83 countries around the world were using wind power on a commercial basis. [ 3 ]
Europe accounted for 48% of the world total wind power generation capacity in 2009. In 2010, Spain became Europe's leading producer of wind energy, achieving 42,976 GWh. Germany held the top spot in Europe in terms of installed capacity, with a total of 27,215 MW as of 31 December 2010. [ 57 ]
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Growth trends
In 2010, more than half of all new wind power was added outside of the traditional markets in Europe and North America. This was largely from new construction in China, which accounted for nearly half the new wind installations (16.5 GW). [ 62 ]
Global Wind Energy Council (GWEC) figures show that 2007 recorded an increase of installed capacity of 20 GW, taking the total installed wind energy capacity to 94 GW, up from 74 GW in 2006. Despite constraints facing supply chains for wind turbines, the annual market for wind continued to increase at an estimated rate of 37%, following 32% growth in 2006. In terms of economic value, the wind energy sector has become one of the important players in the energy markets, with the total value of new generating equipment installed in 2007 reaching €25 billion, or US$36 billion. [ 63 ]
Although the wind power industry was affected by the global financial crisis in 2009 and 2010, a BTM Consult five-year forecast up to 2013 projects substantial growth. Over the past five years the average growth in new installations has been 27.6 percent each year. In the forecast to 2013 the expected average annual growth rate is 15.7 percent. [ 50 ] [ 51 ] More than 200 GW of new wind power capacity could come on line before the end of 2013. Wind power market penetration is expected to reach 3.35 percent by 2013 and 8 percent by 2018. [ 50 ] [ 51 ]
Capacity factor
Since wind speed is not constant, a wind farm's annual energy production is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor . Typical capacity factors are 15–50%, with values at the upper end of the range in favourable sites and are due to wind turbine improvements. [ 65 ] [ 66 ] [ nb 2 ]
Online data is available for some locations and the capacity factor can be calculated from the yearly output. [ 67 ] [ 68 ] For example, the German nation-wide average wind power capacity factor over all of 2012 was just under 17.5% (45867 GW·h/yr / (29.9 GW × 24 × 366) = 0.1746) [ 69 ] [ not in citation given ] and the capacity factor for Scottish wind farms averaged 24% between 2008 and 2010. [ 70 ]
Unlike fueled generating plants the capacity factor is affected by several parameters, including the variability of the wind at the site but also the generator size. A small generator would be cheaper and achieve a higher capacity factor but would produce less electricity (and thus less profit) in high winds. Conversely, a large generator would cost more but generate little extra power and, depending on the type, may stall out at low wind speed. Thus an optimum capacity factor would be aimed for, of around 40–50%. [ 66 ] [ 71 ]
In a 2008 study released by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, the capacity factor achieved by the U.S. wind turbine fleet is shown to be increasing as the technology improves. The capacity factor achieved by new wind turbines in 2010 reached almost 40%. [ 72 ] [ 73 ]
