Wind Energy-Concepts, Current and Future Prospects

Wind power is extracted from air flow using wind turbines or sails to produce mechanical or electrical power. Windmills are used for their mechanical power, windpumps for water pumping, and sails to propel ships. Wind energy as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, and uses little land. The net effects on the environment are generally less problematic than those from nonrenewable power sources.

Wind power is produced by using wind generators to harness the kinetic energy of wind. It is gaining worldwide popularity as a large scale energy source, although it still only provides less than one percent of global energy consumption. Wind turbines operate on a simple principle. The energy in the wind turns two or three propeller-like blades around a rotor. The rotor is connected to the main shaft, which spins a generator to create electricity. Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. View the wind turbine animation to see how a wind turbine works or take a look inside.

Wind is a form of solar energy and is a result of the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface, and the rotation of the earth. Wind flow patterns and speeds vary greatly across the United States and are modified by bodies of water, vegetation, and differences in terrain. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.

The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity. Modern wind turbines fall into two basic groups: the horizontal-axis variety, as shown in the photo to the far right, and the vertical-axis design, like the eggbeater-style Darrieus model pictured to the immediate right, named after its French inventor. Horizontal-axis wind turbines typically either have two or three blades. These three-bladed wind turbines are operated “upwind,” with the blades facing into the wind. Single small turbines, below 100 kilowatts, are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations, where a connection to the utility grid is not available.

Horizontal turbine components include blade or rotor, which converts the energy in the wind to rotational shaft energy; a drive train, usually including a gearbox and a generator; a tower that supports the rotor and drive train; and other equipment, including controls, electrical cables, ground support equipment, and interconnection equipment.

Advantages and Disadvantages of Wind-Generated Electricity

A Renewable Non-Polluting Resource

Wind energy is a free, renewable resource, so no matter how much is used today, there will still be the same supply in the future. Wind energy is also a source of clean, non-polluting, electricity. Unlike conventional power plants, wind plants emit no air pollutants or greenhouse gases.

According to the U.S. Department of Energy, in 1990, California’s wind power plants offset the emission of more than 2.5 billion pounds of carbon dioxide, and 15 million pounds of other pollutants that would have otherwise been produced. It would take a forest of 90 million to 175 million trees to provide the same air quality.

Cost Issues

Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators. Roughly 80% of the cost is the machinery, with the balance being site preparation and installation. If wind generating systems are compared with fossil-fueled systems on a “life-cycle” cost basis (counting fuel and operating expenses for the life of the generator), however, wind costs are much more competitive with other generating technologies because there is no fuel to purchase and minimal operating expenses.

Environmental Concerns

Although wind power plants have relatively little impact on the environment compared to fossil fuel power plants, there is some concern over the noise produced by the rotor blades, aesthetic (visual) impacts, and birds and bats having been killed (avian/bat mortality) by flying into the rotors. Most of these problems have been resolved or greatly reduced through technological development or by properly siting wind plants.

Supply and Transport Issues

The major challenge to using wind as a source of power is that it is intermittent and does not always blow when electricity is needed. Wind cannot be stored (although wind-generated electricity can be stored, if batteries are used), and not all winds can be harnessed to meet the timing of electricity demands.

Further, good wind sites are often located in remote locations far from areas of electric power demand (such as cities).

Finally, wind resource development may compete with other uses for the land, and those alternative uses may be more highly valued than electricity generation. However, wind turbines can be located on land that is also used for grazing or even farming.

Current Prospects

Worldwide there are now over two hundred thousand wind turbines operating, with a total nameplate capacity of 282,482 MW as of end 2012. The European Union alone passed some 100,000 MW nameplate capacity in September 2012, while the United States surpassed 50,000 MW in August 2012 and China’s grid connected capacity passed 50,000 MW the same month.

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 installed capacity in Germany 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. As of 2011, 83 countries around the world were using wind power on a commercial basis.

Wind power capacity has expanded rapidly to 336 GW in June 2014, and wind energy production was around 4% of total worldwide electricity usage, and growing rapidly.

The actual amount of electricity that wind is able to generate is calculated by multiplying the nameplate capacity by the capacity factor, which varies according to equipment and location. Estimates of the capacity factors for wind installations are in the range of 35 to 44%.

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.

Fig. 1: Worldwide installed capacity, 2014…

Fig. 2: Worldwide cumulative capacity, 2014…

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).

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.

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% each year. In the forecast to 2013 the expected average annual growth rate is 15.7%. More than 200 GW of new wind power capacity could come on line before the end of 2014. Wind power market penetration is expected to reach 3.35% by 2013 and 8% by 2018. Several countries have already achieved relatively high levels of penetration, such as 39% of stationary (grid) electricity production in Denmark (2014), 19% in Portugal (2011), 16% in Spain (2011), 16% in Ireland (2012),United Kingdom (2014) – 9.3% and 8% in Germany (2011). For the U.S. in 2013, the penetration level was estimated at 4.5%. Fig. 1 and Fig. 2 show worldwide installed capacity and cumulative capacity respectively for 2014.

Future Prospects

The Global Wind Energy Outlook explores the future of the wind energy industry out to 2020, 2030 and up to 2050. With the International Energy Agency’s New Policies scenario from the World Energy Outlook as a baseline, we have developed two scenarios especially for this publication: the GWEO Moderate scenario and the GWEO Advanced scenario. The GWEO Moderate and Advanced scenarios have evolved over the years as a collaboration between the Global Wind Energy Council, Greenpeace International and the German Aerospace Centre (Deutsches Zentrum fur Luft-und-Raumfahrt – DLR). These scenarios for the future of the wind industry have contributed to an ongoing series of broader studies on global sustainable energy pathways up to 2050 conducted by DLR and Greenpeace in collaboration with a number of industry associations including GWEC. The IEA’s New Policies scenario shows the global wind market returning to 2012 levels in 2016 and then gradually decreasing and stabilizing at about the 2010 market level after 2020, and only growing very slightly from that level out to 2030.

Fig. 3: New Policies Scenario, 2020…

Fig.4: New Policies Scenario, 2030…

Fig. 5: Moderate Scenario, 2020…

Fig. 6: Moderate Scenario, 2030…

Fig. 7: Advanced Scenario 2020…

Fig. 8: Advanced Scenario, 2030…

Fig.9 : Yearwise Mega Watt Production…

The Moderate scenario reflects a world which carries on more or less the way it has for the past decade, with wind power continuing to gain ground but still struggling against heavily subsidized incumbents; without a comprehensive or cohesive carbon market, and with those that exist at very low prices. Policy instability decreases, but is still a factor, although the competition in OECD markets for a larger share of a stable or dwindling pie is intense. The Advanced scenario shows the potential of wind power to produce 25-30% of global electricity demand by the end of the scenario period, where there is a strong international political commitment towards meeting climate goals and national energy policy is driven by the need for enhanced energy security, price stability, job creation and the need to conserve our precious fresh water resources.

The Moderate scenario starts with about 14% growth in 2014, tapering off gradually to 10% by 2020 and then also to 6% by 2030, while the IEA New Policies scenario starts at 12% in 2014, sinking to 7% by 2020 and then to 4% by 2030.

In the Advanced scenario, cumulative growth rates start off well below the historical average at 15%, remain steady in the middle of this decade and then taper off to 13% by the end of the decade, dropping to 6% by 2030. Fig. 3 to Fig. 8 show new policies scenario, moderate scenario and advanced scenario for year 2020 and 2030. Fig. 9 represents yearwise MW production for new policies scenario, moderate scenario and advanced scenario.

Interesting Wind Energy Facts

• The United States currently has 61,110 MW of installed wind project capacity, comprising 5.7% of total U.S. installed electric generating capacity.
• Wind mills have been in use since 2000 B.C. and were first developed in China and Persia.
• Wind power is currently the fastest-growing source of electricity production in the world.
• Iowa and South Dakota generated more than 25% of their energy from wind during 2013.
• A single wind turbine can power 500 homes.
• In 2012, the Shepherds Flat wind project became the largest online wind project in the United States (845 megawatts), breaking the record previously held by the Roscoe Wind Farm (781.5 megawatts).
• In 2013, the roughly 168 million megawatt-hours generated by wind energy avoided 95.6 million metric tons of carbon dioxide (CO2) — the equivalent of reducing power-sector CO2 emissions by 4.4% or removing 16.9 million cars from the roads.
• There’s enough on-shore wind in America to power the country 10 times over.
• In 2013, 12 states accounted for 80% of U.S. wind-generated electricity: Texas, Iowa, California, Oklahoma, Illinois, Kansas, Minnesota, Oregon, Colorado, Washington, North Dakota, and Wyoming. Source: U.S. Energy Information Administration March Electric Power Monthly report.
• Most wind turbines (95%) are installed on private land.
• Modern wind turbines produce 15 times more electricity than the typical turbine did in 1990.
• At times, wind energy produces as much as 25% of the electricity on the Texas power grid.
• American wind power is a $10 billion a year industry.
• Unlike nearly every other form of energy, wind power uses virtually no water.
• By 2030, U.S. wind power will save nearly 30 trillion bottles of water.
• At times, wind power produces as much as 45% of the electricity in Spain.
• Wind energy became the number-one source of new U.S. electricity-generating capacity for the first time in 2012, providing some 42% of all new generating capacity. In fact, 2012 was a strong year for all renewables, as together they accounted for more than 55% of all new U.S. generating capacity.
• During 2013, California led the nation in new wind installations (with 269 megawatts), followed by Kansas, Michigan, Texas, and New York.
• 70% of all U.S. Congressional Districts are home to an operating wind project, a wind-related manufacturing facility, or both.
• As of May 2014, the United States is home to 46,000 operating wind turbines.
• Right now, 559 wind-related manufacturing facilities produce a product for the U.S. wind energy industry across 44 states.
• Both Nevada and Puerto Rico added their first utility-scale projects during 2012.
• In 2000, more than 60% of U.S. wind power capacity was installed in California, with 17 states hosting utility-scale wind turbines. Today, 39 states and Puerto Rico share 60 gigawatts of utility-scale wind project development.
• Wind is a credible source of new electricity generation in the United States. Wind power comprised 43% of all new U.S. electric capacity additions in 2012 and represented $25 billion in new investment. Wind power currently contributes more than 12% of total electricity generation in nine states (with three of these states above 20%), and provides more than 4% of total U.S. electricity supply. Source: 2012 Wind Technologies Market Report (PDF 3.4 MB)
• Wind energy prices have dropped since 2009 and now rival previous lows. Lower wind turbine prices and installed project costs, along with improved capacity factors, are enabling aggressive wind power pricing. After topping out at nearly $70/megawatt-hour in 2009, the average levelized long-term price from wind power sales agreements signed in 2011/2012 – many of which were for projects built in 2012 – fell to around $40/megawatt-hour nationwide.

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