Wind energy is the kinetic energy generated by air flow.solar energyA form of transformation of.Due to the uneven heating of various parts of the earth's surface caused by solar radiation, the pressure distribution in the atmosphere is unbalancedgradientUnder the action of, air moves horizontally to form wind.The total reserves of wind energy resources are huge, and the technically exploitable energy in a year is about 5.3X10 ^ 13 kilowatt hours.Wind energy is renewableclean energyIt has large reserves and wide distribution, but its energy density is low (only 1/800 of water energy) and unstable.Under certain technical conditions, wind energy can be developed and utilized as an important energy source.[1]
Wind energy resources are determined by wind energy density and annual cumulative hours of available wind energy.Wind energy density is the wind power that can be obtained per unit of windward area, which is proportional to the third power of wind speed and air density.
Wind energy is caused by air flowWorkThe available energy provided to human beings belongs to renewable energy (including water energy, bioenergy, etc.).Air flow haskinetic energyIt is called wind energy.The higher the air velocity, the greater the kinetic energy.People can use the windmill to convert the kinetic energy of the wind into rotating action to drive the generator to generate electricity by rotating the rotor (consisting of fan blades driven by aerodynamic force) through the transmission shaftturnThe force is transmitted to the generator.Up to 2008, there are about 94.1 million electricity generated by wind power in the worldKilowattThe electricity supplied has exceeded 1% of the world's consumption.Although wind power is not the main energy source for most countries, it has grown more than four times between 1999 and 2005.
Wind power is used in large-scale wind farms and some places where power supply is cut off, making great contributions to local life and development.
characteristic
Wind energy is rich, nearly endless, widely distributed, clean and mildgreenhouse effect。 It exists within a certain range of the earth surface.The average wind energy density obtained through long-term measurement, investigation and statistics is called the basis for energy utilization within this range, usually based ondot densityMarked on the map.
history
Wind energy
The history of human use of wind energy can be traced back to the Western Yuan Dynasty, but for thousands of years,Wind energy technologyThe slow development has not attracted enough attention.But since the 1973 world oil crisisConventional energyUnder the dual pressure of urgency and the deterioration of the global ecological environment, wind energy, as a part of new energy, has made great progress again.Wind energy as apollution-freeandRenewable new energyIt has great development potential, especially for coastal islands, remote mountainous areas with poor transportation, grasslands and pastures with few people, as well as rural and border areas far away from the power grid and hard to reach in the near futureDomestic energyIt is a reliable way of doing this, which is of great significance.Even in developed countries, wind energy is an efficientClean new energyThey are also increasingly valued, such as:US Department of EnergyI have investigated it, justTexasandSouth DakotaThe wind energy density of the two states is enough to supply the whole United StatesElectricity。
source
Wind energy
Wind is a natural phenomenon on the earth, which is caused bysolar radiationCaused by heat.When the sun shines on the surface of the earth, different parts of the earth's surface are heated differently, resulting in temperature difference, which causes the convection movement of the atmosphere to form wind.Wind energy is the kinetic energy of air, and the size of wind energy depends onwind speedAnd the density of air.The global wind energy is about 2.74X109MW, of which the available wind energy is 2X107MW, which is more than the available wind energyHydroenergyThe total is 10 times larger.The kinetic energy formed by air flow is wind energy.Wind energy is a conversion form of solar energy.The sun's radiation causes uneven heating on the earth's surface, causingatmosphereThe middle pressure distribution is uneven, and the air moves horizontally to form wind.The formation of wind is the result of air movement.
Overview of utilization
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It is estimated that although only about 2% of the solar energy reaching the earth is converted into wind energy, the total amount is still considerable.The global wind energy is about 130 billion kilowatts, 10 times more than the total amount of hydropower that can be developed and utilized on the earth.
The history of human using wind energy can be traced back to BC.Ancient Egypt, ChinaBabylon, CubaIt is one of the first countries in the world to use wind energy.In BC, wind power was used to lift water, irrigate, grind flour, and pound rice, and sails were used to propel ships forward.Due to the shortage of oil, modern sailboats have received great attention in modern times.The Song Dynasty was also the heyday of the application of windmills in China. The popular vertical axis windmill at that time has been used ever since.Abroad, in the 2nd century BC, the ancient Persians used vertical axis windmills to grind rice.In the 10th century, Islam used windmills to carry water. In the 11th century, windmills have been widely used in the Middle East.The windmill was introduced to Europe in the 13th century and became an indispensable prime mover in Europe in the 14th century.Windmills were first used in HollandRhine DeltaThe water drawn from lakes and low wetlands was later used for oil pressing and sawing.It was only because of the emergence of the steam engine that the number of windmills in Europe dropped sharply.
For thousands of years, wind energy technology has developed slowly and has not attracted enough attention.However, since the 1973 world oil crisis, under the dual pressure of the emergency of conventional energy and the deterioration of the global ecological environment, wind energy, as a part of new energy, has made great progress again.Wind energy, as a pollution-free and renewable new energy, has great development potential, especially for coastal islands, remote mountainous areas with inconvenient transportation, grasslands and pastures with sparse population, as well as rural and border areas far away from the power grid and hard to reach in the near future, which is of great significance as a reliable way to solve production and living energy problems.Even in developed countries, wind energy, as an efficient and clean new energy, is also increasingly valued.
The United States began implementing the federal wind energy plan as early as 1974.Its main contents are: to evaluate the nationalWind energy resources；Research on social and environmental issues in wind energy development;Improve the performance of wind turbine and reduce the cost;It mainly studies wind turbines less than 100kw for agriculture and other users;Megawatt wind turbine designed for power companies and industrial users.The United States has successfully developed 100, 200, 2000
Wind energy street lamp
Six kinds of wind turbines of 2500, 6200 and 7200kw.At present, the United States has become the country with the largest installed capacity of wind turbines in the world, more than 2X104MW, with an annual growth rate of 10%.
Now the world's largest new wind turbine hasHawaii IslandWhen the wind turbine is completed and put into operation, its blade diameter is 97.5m, and its weight is 144t. The adjustment of the windward angle of the wind turbine and the operation of the unit are controlled by computers, and the annual power generation reaches 10 million kw · h.According to the statistics of the US Department of Energy, by 1990, wind power generation in the US had accounted for 1% of the total power generation.staySwedenThe Netherlands, the United Kingdom, Denmark, Germany, Japan and Spain have also formulated corresponding wind power generation plans according to their respective national conditions.For example, in Sweden, the installed capacity of wind turbines reached 350MW in 1990, with an annual power generation of 1 billion kw · h.
Denmark was built in 1978Jutland The wind power station has an installed capacity of 2000kw, and the swept diameter of three blades is 54m,Concrete towerIt is 58m high. It is estimated that 10% of the power demand in 2005 will come from wind energy.Germany in 1980Elbe RiverA wind power station with an installed capacity of 3000 kw has been built in QingdaoWind power generationIt will also account for 8% of the total power generation.britain,British IslesNear the sea, wind energy is very abundant, and the government also attaches great importance to wind energy development. By 1990, wind power had accounted for 2% of the total power generation in Britain.
In Japan, the Qingjin Strait in October 1991aomori Japan's largest wind power station has been put into operation, and five wind turbines can provide power for 700 households.China is located in the southeast of the Asian continent, bordering the west coast of the Pacific Ocean, with strong monsoon.Monsoon is the basic feature of China's climate. For example, the winter monsoon lasts for 6 months in North China and 7 months in Northeast China.The southeast monsoon covers the eastern half of China.according toNational Meteorological AdministrationIt is estimated that the total reserves of wind resources in the country are 1.6 billion kw per year, and about 160 million kw can be developed in the near future. The reserves of wind energy in Inner Mongolia, Qinghai, Heilongjiang, Gansu and other provinces are among the top in China, and the days when the annual average wind speed is greater than 3m/s are more than 200 days.
ChinaWind turbineIn the late 1950s, various kinds of wood structure clothAwning windmillIn 1959, there were more than 200000 wooden windmills in Jiangsu Province alone.By the mid-1960s, it was mainly developmentWind powered water extractor。Since the mid-1970s, wind energy development and utilization has been included in the "Sixth Five Year Plan" national key projects, and has developed rapidly.Since the mid-1980s, China has successively introduced a batch of medium and large enterprises from Denmark, Belgium, Sweden, the United States and GermanyWind power generatorGroup.Eight demonstration wind farms have been set up in Xinjiang, Inner Mongolia and Shandong, Zhejiang, Fujian and Guangdong islands.In 1992, the installed capacity reached 8MW.XinjiangDabanchengIts installed capacity has reached 3300kw, making it the largest wind farm in China.By the end of 1990, the irrigation area of wind powered water pumping had reached 25800 mu.In 1997, 100000 kw of wind power was added.At present, China has developed more than 100 different types of wind turbines with different capacities, and has initially formed the wind turbine industry.However, compared with developed countries, the development and utilization of wind energy in China is still quite backward. It is not only slow in development but also backward in technology, far from forming a scale.When entering the 21st century, China should increase investment in the development and utilization of wind energy, so that efficient and clean wind energy can occupy its due place in China's energy pattern.
After several ups and downs, the development of the global wind energy industry has finally turned around, and will usher in a new round of boom.
2013 is undoubtedly a blow to the global wind energy industry, but there are also some commendable points.
In the United States, the most prosperous wind energy industry is in Texas, which has 12400 MW of wind power installed capacity.The contribution of wind energy to the state's power grid is also growing.
In 2010, China has surpassed the wind power capacity of the United States and become the world's largest wind power producer.China also plans to add 39 megawatts of offshore wind power development.
In addition, wind power projects are also in full swing in other parts of Asia.For example, in Pakistan, the total installed capacity of wind power in 2013 doubled from 2012 to 100 MW. With the implementation of two 50 MW wind power projects launched in 2014, the total installed capacity will double again.Similarly, Thailand doubled its total installed wind power capacity to 220 MW in 2013.The seven projects completed in the Philippines in 2014 expanded the country's installed wind power capacity to 450 MW, an increase of 13 times.
It can be seen that after the dormancy in 2013 and the accumulation of power in 2014, the global wind energy industry will usher in a new upsurge of development and even create a new record.[2]
Form of utilization
The main form of wind energy utilization is to convert the kinetic energy of the atmosphere into other forms of energy.The wind isHorizontal movementThe movement of air is mainly caused by the latitude of the earthSolar radiation intensityDifferent.In equatorial and low latitude regions, the solar altitude angle is large,sunshineLong time, strong solar radiation intensity, more heat received by the ground and atmosphere, and higher temperature;In high latitudes, the solar altitude angle is small, the sunshine time is short, the heat received by the ground and atmosphere is small, and the temperature is low.This temperature difference between high latitude and low latitude forms the pressure gradient between the north and south of China, making the air move horizontally.
monsoon
Theoretically, the wind should blow along the horizontal pressure gradient, that is, the vertical and isobaric lines blow from high pressure to low pressure, but the earthrotation, the force that deflects the horizontal movement of air, calledcoriolis force This force deflects the air flow in the northern hemisphere to the right and the southern hemisphere to the left, soEarth's atmosphereBesides the pressure gradient force, the movement is also affected by the geostrophic deflection force.The real motion of the atmosphere is the resultant force of these two forces.In fact, the surface wind is not only dominated by these two forces, but also affected to a large extent by the ocean and terrain. Mountain passes and straits can change the direction of airflow movement, and can also increase the wind speed. However, the friction of hills and mountains reduces the wind speed, and the wind speed of isolated mountains increases due to the high altitude.Therefore, the wind direction and wind speedspace-timeThe distribution is complex.For example, the difference between sea and land has an impact on the air flow movement. In winter, the continent is colder than the ocean, the continental pressure is higher than the ocean, and the wind blows from the continent to the ocean;In summer, on the contrary, the mainland is hotter than the ocean, and the wind blows inland from the ocean.This kind of wind that changes with the seasons is called monsoon.
Sea land breeze
Wind energy
So calledSea land breezeAlso in the daytime, the air flow on the continent is heated and expands to the upper air to flow to the ocean, and then cools and sinks over the ocean. The air flow on the near surface ocean blows to the continent to compensate for the updraft on the continent. The low-level wind blowing from the ocean to the continent is called the sea breeze. At night (winter), the situation is opposite. The low-level wind blowing from the continent to the ocean is called the land breeze.In mountainous areas, due to thermal reasons, it blows from the valley to the plain or mountain slope in the daytime, and from the plain or mountain slope to the bottom of the valley at night. The former is called valley wind, and the latter is called mountain wind.This is because the hillside is heated quickly during the day, and the temperature is higher than the air temperature at the same height above the valleyWarm airFrom the hillside to the top of the valley, the air in the valley will supplement the lost air along the hillside. At this time, the wind blowing from the valley to the hillside is called valley wind.At night, the slope is cooled by radiation, and the cooling rate is faster than the air at the same height. The cold air flows down the slope into the valley, which is called mountain breeze.
WhenSolar radiant energyWhen crossing the earth's atmosphere, the atmosphere absorbs about 2 * 10 ^ 16W of energy, a small part of which is converted into the kinetic energy of the air.Because the tropical and subtropical zones absorb more solar radiation energyatmospheric pressurePoor air flow causes wind.As for local areas, for example, in high mountains and deep valleys, in the daytime, the air on the high mountain top is heated by the sun and rises, and the cold air in the deep valley takes its place. Therefore, the wind blows from the deep valley to the high mountains;At night, the air on the mountain dissipates heat faster, so the wind blows from the mountain to the valley.Another example, for example, in coastal areas, the sea wind blows to land due to the temperature difference between land and sea during the day;On the contrary, it blows from land to sea at night.
Wind energy
1% to 3% of the solar energy absorbed by the earth is converted into wind energy, which is equivalent to that all plants on the earth absorb solar energy through photosynthesis and convert it into wind energychemical energy50 to 100 times.The energy of wind can be found at high altitude, where there are strong winds with a speed of more than 160 km/h (100 miles, 160 km/h, 100 mph).The energy of these winds is finally released in various forms of heat energy due to the friction between the surface and the atmosphere.
Cause of wind: the uneven solar radiation on the polar and equatorial regions makes the surface unheated;The speed of surface temperature is faster than that of sea surface;The stratosphere in the atmosphere, like the ceiling effect, accelerates the convection of gas;Seasonal/change;Coriolis effect;The reflection ratio of the moon forms the wind.
Wind energy can be extracted by windmill.When the wind blows the wind wheel, the wind drives the wind wheel to rotate around the shaft, so that the wind energy can be converted into mechanical energy.The amount of wind energy conversion is directly related toAir densityThe area swept by the wind wheel is proportional to the square of the wind speed.The area swept by the air mass flow through the wind wheel varies with the wind speed and air density.For example, on a cool day at 15 ° C (59 ° F), the air density at sea level is 1.22 kilograms per cubic meter (the air density will decrease when the humidity increases).When the wind blows through a wheel with a diameter of 100 meters at a speed of 8 meters per second, it can make 1000000000 kilograms of air pass through the area swept by the wheel per second.
The kinetic energy of the specified mass israteIs proportional to the square of.Because the mass flow increases linearly with the wind speed, the wind energy effectively used for the wind wheel will be proportional to the cube of the wind speed;In this example, the power of the wind turbine is about 2.5 millionwatt。
Because the wind turbine extracts energy, the air slows down, causing it to spread and to some extent restrain it near the wind turbine.Albert Betz, a German physicist, determined in 1919 that the wind turbine could extract up to 59% of the energy that would otherwise flow through the turbine's cross-section.Regardless of the turbine design, Betz limits apply.The latest work is about 30% of the theoretical limit next to the thruster type turbines.The actual efficiency ranges from 1% to 20% for propeller type turbines, and is as high as 35% for three-dimensional vertical axis turbines like Darrieus or Gorlov turbines.
2002 at Lee Farm facility in Colorado
There is wind variation, and the average value of a measured site alone does not indicate that the wind turbine may cause a considerable amount of energy there.In order to estimate wind speed and soil in a special place, the probability distribution function is often suitable for the observed data.Different locations will have different wind speeds.The distribution model most frequently used to shape wind speed is a two parameter Weibull distribution, because it can follow a variety of distribution shapes, from Gauss to exponential.Rayleigh modeling, for example, which is plotted against the actually measured data set on the right, is a specific form of the Weibull effect of the shape parameter total 2 and very closely reflects the actual distribution of hourly wind speed in many places.Since many electric energy is generated by high wind speed, the available energy mostly comes from the instantaneous high wind speed.More than half of the available energy only accounts for 15% of the operating time. Therefore, unlike coal-fired power plants that use fuel, they can adjust their power generation according to the power demand.Since the wind speed is not constant, the annual power generation of wind power generation is not the marked power generation rate multiplied by all operating hours (within one year). The actual value and the theoretical value (maximum value) are called capacity factors.The capacity factor of a well installed wind turbine can reach 35%. Compared with the turbines of power plants using common fuels, the wind turbine with a capacity of 1000 kW can generate up to 350 kW of electricity per yearoutput powerIt is difficult to predict, but the annual change in power generation should be within a few percent.When storage, such as the storage of water and electricity pumped by pumps, or other forms of generation are used to "shape" the wind power (by ensuring the reliability of continuous delivery), commercial delivery represents about 25% of the cost increase, yielding to the dynamic business performance.
Energy classification
The strength of the wind is usually expressed by the wind power level, which can be estimated by the situation of ground or sea surface objects being moved by the wind.At present, the wind estimation commonly used internationally is based onBeaufort scaleIs standard.Beaufort, an admiral of the British navy, first established the wind classification standard in 1805.It was first used only on the sea, and then on the land. It has been revised repeatedly, and has become the current wind level.The empirical relationship between the actual wind speed and the Beaufort scale is:
V= 0.836 * (B ^ (3/2))
B is the Beaufort wind series, V is the wind speed (unit: m/s)
Generally speaking, when the wind speed of the wind turbine is 2.5 m/s and the wind is felt on the face and the leaves shake, the wind turbine has started to generate electricity. When the wind speed reaches 28~34 m/s, the wind turbine will automatically detect and stop running to reduce the damage to the receptor itself.
For more information about wind energy, please refer to the book Wind Resources and Micro Site Selection: Theoretical Basis and Engineering Application, written by Zhang Huaiquan.
Wind energy
Advantages and disadvantages
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advantage
Wind turbines on the grasslands of Inner Mongolia
Wind energy is a clean energy source.Wind energy facilities are improving day by day. Mass production reduces the cost. In appropriate locations, the cost of wind power generation is lower than that of other generators.
Wind energy facilities are mostly non three-dimensional facilities, which can protect land and ecology.[3]
Wind power generation is a renewable energy, very environmentally friendly, very clean.
Energy saving and environmental protection of wind power generation.
shortcoming
The ecological problem of wind power generation is that it may interfere with birds, such as the United StatesKansasAfter the emergence of windmill, the grouse of.The current solution is offshore power generation, which has high price but high efficiency.
In some regions, the economy of wind power generation is insufficient: the wind power in many regions is intermittent, and the worse situation is that in Taiwan and other places, in the summer and daytime when the power demand is high, the wind power is low;Must waitcompressed airetc.Energy storage technologydevelopment.[4]
Wind power generation requires a large amount of land to build wind power generationelectric fieldCan produce more energy.
When conducting wind power generation, the wind turbine will generate hugenoise, so we need to find some empty places to build.
The current wind power generation is not yet mature, and there is still considerable room for development.
4) Wind energy is a new type of energy, and the corresponding equipment is not very mature.
5) It is suitable for use in places with open terrain, few obstacles or high terrainWind power generation。
economic outlook
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economic value
The cost of using wind to generate electricity has been greatly reduced. Even if other external costs are not included, the cost of using wind power in many appropriate places is lower than that of using diesel engines to generate electricity.The annual growth rate of wind power generation was about 25% in 2002, but now it is growing rapidly at 38%.In 2003, the growth rate of wind power generation in the United States exceeded the average growth rate of all generators.Since 2004, wind power has become the cheapest of all new energy sources.In 2005, the cost of wind energy has dropped to one fifth of that in the 1990s, and with the use of large wattage generators, the downward trend will continue.
Spain
La Muela is located in Aragon, northeast of Spain, with a total area of 143.5 square kilometers.Since 1980, the new mayor has been optimistic about the abundant northeast wind resources and vigorously promoted wind power generation.In the past 20 years, 450 fans (rated capacity of 237MW) have been built in succession, bringing rich benefits to the local area.The local government has also taken advantage of the well planned town welfare to attract many people to move here. In just five years, the number of residents has increased from 4000 to 12000.La Muela has changed from an unknown wilderness town to a well-known place for sightseeing and leisure.
France
In addition, Bouin in the northwest of France originally produced oysters andsea saltFamous, 8 seats since July 1, 2004Wind turbineOfficially put into operation, these eight fans, together with oysters and sea salt, have become the tourist characteristics of this town, attracting a large number of tourists from all over the country to visit, bringing abundant tourism income.
Taiwan, China
Formation of sea land breeze
As the Cape of Good Hope in Houlong Town, Miaoli County, Taiwan, is located at the commanding height of coastal hills, it was a view in the early yearsTaiwan StraitIn recent years, foreign businessmen have set up 21 wind turbines with a height of 100 meters in the adjacent areas, creating a beautiful scene.In 2003, the company was interested inMiao chestnutStrong coastal winterNortheast monsoonWe started to set up wind turbines in Houlong, Zhunan and other places. Among them, Dapeng Wind Farm was set up in Houlong, with 21 wind turbines and a total power generation capacity of 42000 kw. It is the largest wind farm in the whole Taiwan at present. After its completion and opening in June 2006, it has become a new tourist attraction, attracting many people to visit.The Cape of Good Hope is located at the top of Bantianliao. Four or five wind turbines can be seen to the north, and three or four wind turbines can also be seen to the south. With the Shanghai Railway running down the mountain and facing the broad Taiwan Strait, the scenery is quite fascinating, and it has become one of the best scenic spots to enjoy wind turbines.
Main technologies
① Horizontal axis wind turbine technology.Because the horizontal axis wind turbine has the advantages of high wind energy conversion efficiency and shorter rotating shaft, it has become the mainstream model of wind power development in the world, and occupies more than 95% of the market share.The vertical axis wind turbine developed in the same period has a small market share and a limited number of applications due to its long rotating shaft, low wind energy conversion efficiency, and difficulties in starting, stopping, and pitching. However, due to its advantages of all wind direction wind control and speed change devices and generators that can be placed under the wind turbine (or on the ground), in recent years,Relevant international research and development are also ongoing and have made some progress.
② The single unit capacity of wind turbine continues to increase, and the utilization efficiency continues to improve.In recent years, the single unit capacity of wind turbines in the world wind power market has continued to increase. The world's mainstream models have increased from 500~1000 kW in 2000 to 2~3 MW in 2004. At present, the largest single unit capacity of wind turbines in operation in the world is 5 MW, and the design and research and development of 10 MW wind turbines have begun.
③ Offshore wind power technology becomes the development direction.At present, the cost of building offshore wind farms is 1.7~2 times of that of onshore wind farms, while the power generation is 1.4 times of that of onshore wind farms, so its economy is still inferior to that of onshore wind farms. With the continuous development of technology, the cost of offshore wind power will continue to decrease, and its economy will gradually highlight.
④ Variable pitch, variable speed and power regulation technologies are widely used.As the variable pitch power regulation mode has the advantages of stable, safe and efficient load control, it has been widely used on large wind turbines this year.
⑤ Direct drive, full power converter technology has developed rapidly.The direct extraction without gearbox can effectively reduce the unit failure caused by gearbox problems, effectively improve the operation reliability and life of the system, and reduce the maintenance cost. Therefore, it is favored by the market and its market share is expanding.
⑥ New type vertical axis wind turbine.It adopts completely different design concepts, and uses new structures and materials to achieve good performance such as light wind start, no noise, resistance to typhoon above level 12, and not affected by wind direction. It can be widely used in small and medium-sized applications such as villas, multi-storey and high-rise buildings, street lamps, etc.The wind solar hybrid power generation system based on it has the advantages of stable power output, high economy and low impact on the environment, and also solves the impact of solar energy development on the power grid.[5]
Encouraging policies of various countries
Since the 1980s, wind power has been valued by European and American countries, and the global wind power generation has grown at an astonishing rate of 30% every year.Renewable energy promotion systems in the world can be divided into:
Fixed price systems: the government formulates a preferential purchase price for renewable energy, and the market determines the quantity.The main methods include:
1. Investment subsidies: DenmarkGermanyIn the early stage of wind power development, Spain and other countries adopted equipment subsidies
2. Fixed feed in tariff: Germany, Denmark and Spain
3. Fixed premium systems
4. Tax credits: America
Fixed quantity systems: also calledRenewable energyThe renewable quota system (referred to as Renewable Portfolio Standard in the United States) is defined by the government for renewable energy power generation, and the price is determined by the market.The main methods include:
2. tradable green certificate systems: UKSweden、Belgium, Italy and Japan
The purpose of the two promotion systems is to protect the market and make renewable energy more investment efficient in the power market through the power of the government. The ultimate purpose is to improve technology and reduce costs, so as to ensure that renewable energy can be used in the free market in the futureTraditional energyCompetition.
Growth trend of countries
According to the latest research report issued by Deutsche Bank, the global wind power development is entering a stage of rapid expansion, and the wind energy industry will maintain an annual growth rate of 20%. By 2015, the total output value of the industry will increase to five times the current level.
From the current technical maturity and economic feasibility, wind energy is the most competitive.In the medium term, the prospects of the global wind energy industry are quite optimistic. The renewable energy incentive policies constantly introduced by governments of various countries will provide a rapid development of the industry in the next few years
Development of offshore wind energy
Development provides great impetus.
It is expected that Asia and the Americas will become the regions with the most growth potential in the coming years.The installed capacity of wind power in China will grow at a high speed of 30% every year, and the wind power in India will also maintain an annual growth rate of 23%.India encourages large enterprises to invest in the development of wind power and implements preferential policies to encourage wind power manufacturing bases. At present, India has become the fifth largest wind power producer in the world.In the United States, with the introduction of new energy policies, the wind energy industry will achieve an extraordinary development of 25% every year.In Europe, Germany's wind power development is in a leading position, among whichWind power equipmentManufacturing has replaced automobile manufacturing and shipbuilding.In the long-term plan for wind power development formulated by Germany recently, it is pointed out that wind power should account for 25% of the total power consumption by 2025 and 50% by 2050.
The growth rate of European countries, which have always been in the leading position in the field of wind energy, will slow down, and it is expected to maintain an annual growth rate of 15% by 2015.Among them, the construction of onshore wind farms in countries that first developed wind energy, such as Germany and Denmark, is basically saturated, and the next major development direction is offshore wind farms and equipment upgrading.Britain, France and other countries still have great potential, and the growth rate will be higher than the average of 15%.
At present, Germany is still the worldWind power technologyThe most advanced country.The installed capacity of wind power in Germany accounts for 28% of the world, while the total production of wind power equipment in Germany accounts for 37% of the global market.With the domestic market gradually saturated, export has become the main growth point of German wind power equipment companies.
The German government will support the industry to maintain its leading position through technological innovation through price subsidies and other means.This year, Germany will revise the Renewable Energy Law again to increase the subsidy price for offshore wind farm access from 9.1 euro cents per kilowatt hour to 14 euro cents.
In China, the country in 2006NDRCThe Conference, the Ministry of Science and Technology, the Ministry of Finance and other eight departments jointly issued the Opinions on the Implementation of Ten Key Energy Conservation Projects in the Eleventh Five Year Plan.According to the standards of ten key energy conservation projects and the policy guidance of the government to support the environmental protection and energy conservation industry, the energy-saving renovation of industrial equipment, building energy conservation, oil saving and oil substitution, and renewable energy will be developed rapidly in the future.
At present, according to industry magazines《Wind energy world》According to the record, the hottest renewable energy in the Chinese market, such as wind energy, solar energy and other industries.Wind energy resources are more renewable, inexhaustible and pollution-free, with high comprehensive social benefits.Moreover, wind power technology is the most mature and low-cost.According to the "Eleventh Five Year Plan" national wind power development plan, the national wind power installed capacity will reach 5 million kilowatts in 2010 and 30 million kilowatts in 2020.By the end of 2006, about 91 wind farms had been built or were under construction, with a total installed capacity of only 2.6 million kilowatts.It can be seen that the fan market has an attractive prospect and broad development space.
Current situation in China
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Reserves and distribution
China is located in the eastern part of the Asian continent, bordering the Pacific Ocean. The monsoon is strong, and there are many mountains in the interior. The terrain is complex. In additionQinghai Tibet PlateauStanding in the west of China, it has changed the pressure distribution and atmospheric circulation caused by land and sea influence, and increased the complexity of China's monsoon.The winter wind comes from the interior of Siberia, Mongolia and other middle and high latitudes, where the air is very cold, dry and cold. When the cold air accumulates to a certain extent, under the guidance of favorable upper air circulation, it will break out southward, commonly known ascold waveUnder the control and influence of the frequent southward strong cold air, the cold and dry northwest wind has formed and attacked the northern provinces (municipalities and autonomous regions) of China.Every winter, there are many times of strong cold air with sharp cooling down to the south, which mainly affects the northwest, northeast and north China, and does not disappear until the next spring and summer.The summer monsoon is the southeast wind from the Pacific Ocean, the southwest wind from the Indian Ocean and the South China Sea, and the southeast monsoon affects the eastern half of China,Southwest monsoonIt will affect the southwest provinces and the southern coast, but the wind speed is far less than the southeast monsoon.Tropical storms are air whirlpools formed on the tropical seas of the western Pacific Ocean and the South China Sea, and they are extremely destructive ocean storms. They frequently attack China in summer and autumn every year, landing on the coast of the South China Sea and the southeast coast of China. Tropical storms can also land north of Shanghai, but only rarely.[6]
jiuquan The first 10 million kilowatt super large wind power base in China has been built, which is the most important wind power base in China.
Qinghai Tibet PlateauThe terrain is high and open. In winter, southerly wind prevails in the southeast, northeasterly wind prevails in the northeast, and westerly wind prevails in other regionsThe Tanggula mountainsAs the boundary, southeast wind prevails in the south, and east to northeast wind prevails in the north.China has a vast territory, with a total length of more than 20000 kilometers of land and more than 18000 kilometers of coastline. There are more than 5000 islands in the marginal sea, which is rich in wind energy resources.The annual average wind speed of the existing wind farm sites in China is more than 6m/s.It is generally believed that wind conditions of wind farms can be divided into three categories: when the annual average wind speed is more than 6m/s, it is better;More than 7 m/s is good;More than 8 meters/second is good.According to wind speed frequency curve and unitPower curve, estimate the annual power generation of the unit under international standard atmospheric conditions.In China, the area equivalent to more than 6m/s is only limited to a few areas nationwide.In terms of inland, it only accounts for 1/100 of the total area of the country, mainly distributed inYangtze RiverThe southeast coast and islands between Nan'ao Island are the largest wind energy resource areas and wind energy resource rich areas in China, including Shandong, Liaodong Peninsula, the coast of the Yellow Sea, the coast of the South China Sea to the west of Nan'ao IslandHainan IslandAnd South China Sea Islands, Inner MongoliaYinshan MountainsNorth toGreater Khingan RangeTo the north, Dabancheng, Xinjiang, Alataw Pass,Hexi Corridor, the lower reaches of the Songhua River, northern Zhangjiakou and other areas, as well as high mountains and mountain peaks distributed everywhere.
According to the statistics and calculation of some wind energy data from the national meteorological observatory, the wind energy zoning in China and its percentage in the national area are shown in the table below.
index
Rich area
More abundant areas
Available area
Impoverished area
Annual effective wind energy density (W/㎡)
>200
150-200
50-150
Annual ≥ 3m/s cumulative hours (h)
>5000
4000-5000
2000-4000
Annual ≥ 6m/s cumulative hours (h)
>2200
1500-2200
350-1500
Percentage in national area (%)
eight
eighteen
fifty
twenty-four
Table China's wind energy zoning and its percentage in the national area
About 2% of the energy radiated by the sun to the earth's surface is converted into wind energy, which isNatural energyAs a part of, the estimation of China's wind energy potential is as follows: the theoretical total exploitable amount of wind energy (R) is 3.226 billion kilowatts nationwide, and the actual exploitable amount (R ') is estimated by l/10 of the total amount, and taking into account that the actual swept area of the wind turbine is 0.785 times of the calculated air flow square area (the area of a 1m diameter wind turbine is 0.5²×π=0.785 (square meters)], so the actual exploitable quantity is: R '=0.785R ÷ 10=253 (100 million kilowatts).
China is a big energy importer, so it is urgent to use renewable energy. Especially in China's vast rural areas rich in wind resources, the Chinese government should increase subsidies for the purchase of wind power equipment, including subsidies for solar panel roofs. If the country's rural household electricity is half self-sufficient, it can save more than 2 billion kilowatt hours of electricity every year.It is hoped that the state will strengthen its operation in this regard.
Develop potential
[4]
The total reserve of wind energy resources at 10m altitude in China is 3.226 billion kW, includingWind energy resource reserves253 million kW.
The southeast coast and its adjacent islands are rich in wind energy resources,Effective wind energyThe isoline with density greater than or equal to 200W/㎡ is parallel tocoastline；The effective wind energy density of coastal islands is more than 300W/㎡, and the number of hours with wind speed greater than or equal to 3m/s throughout the year is about 7000~8000h, and the number of hours with wind speed greater than or equal to 6m/s is 4000h.
jiuquan North Xinjiang and Inner Mongolia are also regions rich in wind energy resources in China. The effective wind energy density is 200~300W/㎡. The annual wind speed is greater than or equal to 3m/s for more than 5000h, and the annual wind speed is greater than or equal to 6m/s for more than 3000h.
Heilongjiang, eastern Jilin, northern Hebei andLiaodong PeninsulaThe wind energy resources are also good, the effective wind energy density is more than 200W/㎡, the annual wind speed is greater than or equal to 3m/s for 5000h, and the annual wind speed is greater than or equal to 6m/s for 3000h.
Qinghai Tibet PlateauThe effective wind energy density in the north is between 150~200W/㎡. The number of hours when the annual wind speed is greater than or equal to 3m/s is 4000~5000h, and the number of hours when the annual wind speed is greater than or equal to 6m/s is 3000h;However, the Qinghai Tibet Plateau has a high altitude and low air density, so the effective wind energy density is also low.
Yunnan, Guizhou, Sichuan, Gansu (exceptjiuquan ）, mountainous areas in southern Shaanxi, Henan, western Hunan, Fujian, Guangdong, Guangxi and XinjiangTarim BasinAnd TibetanThe Yarlung Zangbo River, is an area with poor wind energy resources, the effective wind energy density is below 50W/㎡, the number of hours with annual wind speed greater than or equal to 3m/s is below 2000h, and the number of hours with annual wind speed greater than or equal to 6m/s is below 150h,Wind energy potentialVery low.[7]
On April 4, 2023, the China Meteorological Administration issued the Annual Outlook Bulletin of China's Wind and Solar Energy Resources in 2022.The bulletin shows that in 2022, the national wind energy resources will be a normal slightly smaller year, and the annual average wind speed at the height of 10 meters will be 0.82% smaller than the average value in recent 10 years.From the perspective of spatial distribution, the wind energy resources at a common installation height of 70 meters for wind turbines in the east of Northeast China, the middle east of Inner Mongolia, the north and east of Xinjiang, the west and north of Gansu, and most of the Qinghai Tibet Plateau are better, which is conducive to wind power generation.[8]
On May 8, 2024, the global energy think tank Ember released a report saying that solar energy is the main source of global power growth in 2023, and also the development highlight of renewable energy.Solar energy has maintained its position as the fastest growing power source for the 19th consecutive year, and surpassed wind energy as the largest new power source for the second consecutive year.[9]
