Wind power is the conversion of wind energy into a useful form of energy, such as using: wind turbines to make electrical power, windmills for mechanical power, wind pumps for water pumping or drainage, or sails to propel ships.
Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation and uses little land. Any effects on the environment are generally less problematic than those from other power sources.
[Wind power plant in Xinjiang, China]
WIND TURBINES
Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. Offshore wind farms can harness more frequent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Small onshore wind facilities are used to provide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines.
Wind energy is an indirect form of solar energy. It is estimated that between 1% and 3% of the solar energy that strikes the Earth is used in the creation of wind. Wind is created by the uneven heating of the Earth's atmosphere. This effect creates high and low pressure systems in the atmosphere. Air moves from the high-pressure systems to low pressure systems, creating the winds that circulate the earth. The wind has kinetic energy. A wind generator converts kinetic energy to electrical energy.
WIND ENERGY
Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind speed doubles. Wind turbines for grid electricity therefore need to be especially efficient at greater wind speeds.
Wind is the movement of air across the surface of the Earth, affected by areas of high pressure and of low pressure. The surface of the Earth is heated unevenly by the Sun, depending on factors such as the angle of incidence of the sun's rays at the surface (which differs with latitude and time of day) and whether the land is open or covered with vegetation. Also, large bodies of water, such as the oceans, heat up and cool down slower than the land. The heat energy absorbed at the Earth's surface is transferred to the air directly above it and, as warmer air is less dense than cooler air, it rises above the cool air to form areas of high pressure and thus pressure differentials. The rotation of the Earth drags the atmosphere around with it causing turbulence. These effects combine to cause a constantly varying pattern of winds across the surface of the Earth.
[Roscoe Wind Farm in USA]
WIND FARMS
A wind farm is a group of wind turbines in the same location used for production of electricity. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore.
Almost all large wind turbines have the same design — a horizontal axis wind turbine having an upwind rotor with three blades, attached to a nacelle on top of a tall tubular tower. In a wind farm, individual turbines are interconnected with a medium voltage (often 34.5 kV), power collection system and communications network. At a substation, this medium-voltage electric current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.
Many of the largest operational onshore wind farms are located in the US. As of 2012, the Alta Wind Energy Center is the largest onshore wind farm in the world at 1020 MW, followed by the Shepherds Flat Wind Farm (845 MW), and the Roscoe Wind Farm (781.5 MW). As of November 2010, the Thanet Wind Farm in the UK is the largest offshore wind farm in the world at 300 MW, followed by Horns Rev II (209 MW) in Denmark.
VARIABILITY and INTERMITTENCY
Electricity generated from wind power can be highly variable at several different timescales: hourly, daily, or seasonally. However, wind is always in constant supply somewhere, making it a dependable source of energy because it will never expire or become extinct. Annual variation also exists, but is not as significant. Like other electricity sources, wind energy must be scheduled. Wind power forecasting methods are used, but predictability of wind plant output remains low for short-term operation. There is an 80% chance that wind output will change less than 10% in an hour and a 40% chance that it will change 10% or more in 5 hours. Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, this variability can present substantial challenges to incorporating large amounts of wind power into a grid system. Intermittency and the non-dispatch able nature of wind energy production can raise costs for regulation, incremental operating reserve, and (at high penetration levels) could require an increase in the already existing energy demand management, load shedding, storage solutions or system interconnection with HVDC cables. At low levels of wind penetration, fluctuations in load and allowance for failure of large generating units require reserve capacity that can also compensate for variability of wind generation. Wind power can be replaced by other power sources during low wind periods. Transmission networks must already cope with outages of generation plant and daily changes in electrical demand. Systems with large wind capacity components may need more spinning reserve (plants operating at less than full load).
[Windmills are typically installed in favorable windy locations. In the image, wind power generators in Spain, near an Osborne bull.]
WIND POWER IN INDIA
The development of wind power in India began in the 1990s, and has significantly increased in the last few years. Although a relative newcomer to the wind industry compared with Denmark or the United States, India has the fifth largest installed wind power capacity in the world. In 2009-10 India's growth rate was highest among the other top four countries.
Initial cost for wind turbines is greater than that of conventional fossil fuel generators per MW installed. Noise is produced by the rotor blades. This is not normally an issue in the locations chosen for most wind farms and research by Sanford University shows that noise complaints for wind farms in the UK are almost non-existent.
[ Wind farm in Muppandal, Tamil Nadu.]
FUTURE
The Ministry of New and Renewable Energy (MNRE) has fixed a target of 10,500 MW between 2007–12, but an additional generation capacity of only about 6,000 MW might be available for commercial use by 2012.
The Ministry of New and Renewable Energy (MNRE) has announced a revised estimation of the potential wind resource in India from 49,130 MW assessed at 50m Hub heights to 102,788 MW assessed at 80m Hub height. The wind resource at higher Hub heights that are now prevailing is possibly even more.
BENEFITS
- Wind energy is an indirect form of solar energy and is free.
- It is a renewable energy source.
- There are no dangerous emissions.
- Wind power can be used in remote areas.
- Wind power can be used in conjunction with other renewable energy resources.
[Livestock ignore wind turbines, and continue to graze as they did before wind turbines were installed.]
----There is no energy crisis, only a crisis of ignorance. We simply must balance our demand for energy with our rapidly shrinking resources. By acting now we can control our future instead of letting the future control us.
BY
V.MAHESH (10H71A0218)
Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation and uses little land. Any effects on the environment are generally less problematic than those from other power sources.
[Wind power plant in Xinjiang, China]
WIND TURBINES
Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. Offshore wind farms can harness more frequent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Small onshore wind facilities are used to provide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines.
Wind energy is an indirect form of solar energy. It is estimated that between 1% and 3% of the solar energy that strikes the Earth is used in the creation of wind. Wind is created by the uneven heating of the Earth's atmosphere. This effect creates high and low pressure systems in the atmosphere. Air moves from the high-pressure systems to low pressure systems, creating the winds that circulate the earth. The wind has kinetic energy. A wind generator converts kinetic energy to electrical energy.
WIND ENERGY
Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind speed doubles. Wind turbines for grid electricity therefore need to be especially efficient at greater wind speeds.
Wind is the movement of air across the surface of the Earth, affected by areas of high pressure and of low pressure. The surface of the Earth is heated unevenly by the Sun, depending on factors such as the angle of incidence of the sun's rays at the surface (which differs with latitude and time of day) and whether the land is open or covered with vegetation. Also, large bodies of water, such as the oceans, heat up and cool down slower than the land. The heat energy absorbed at the Earth's surface is transferred to the air directly above it and, as warmer air is less dense than cooler air, it rises above the cool air to form areas of high pressure and thus pressure differentials. The rotation of the Earth drags the atmosphere around with it causing turbulence. These effects combine to cause a constantly varying pattern of winds across the surface of the Earth.
[Roscoe Wind Farm in USA]
WIND FARMS
A wind farm is a group of wind turbines in the same location used for production of electricity. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore.
Almost all large wind turbines have the same design — a horizontal axis wind turbine having an upwind rotor with three blades, attached to a nacelle on top of a tall tubular tower. In a wind farm, individual turbines are interconnected with a medium voltage (often 34.5 kV), power collection system and communications network. At a substation, this medium-voltage electric current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.
Many of the largest operational onshore wind farms are located in the US. As of 2012, the Alta Wind Energy Center is the largest onshore wind farm in the world at 1020 MW, followed by the Shepherds Flat Wind Farm (845 MW), and the Roscoe Wind Farm (781.5 MW). As of November 2010, the Thanet Wind Farm in the UK is the largest offshore wind farm in the world at 300 MW, followed by Horns Rev II (209 MW) in Denmark.
VARIABILITY and INTERMITTENCY
Electricity generated from wind power can be highly variable at several different timescales: hourly, daily, or seasonally. However, wind is always in constant supply somewhere, making it a dependable source of energy because it will never expire or become extinct. Annual variation also exists, but is not as significant. Like other electricity sources, wind energy must be scheduled. Wind power forecasting methods are used, but predictability of wind plant output remains low for short-term operation. There is an 80% chance that wind output will change less than 10% in an hour and a 40% chance that it will change 10% or more in 5 hours. Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, this variability can present substantial challenges to incorporating large amounts of wind power into a grid system. Intermittency and the non-dispatch able nature of wind energy production can raise costs for regulation, incremental operating reserve, and (at high penetration levels) could require an increase in the already existing energy demand management, load shedding, storage solutions or system interconnection with HVDC cables. At low levels of wind penetration, fluctuations in load and allowance for failure of large generating units require reserve capacity that can also compensate for variability of wind generation. Wind power can be replaced by other power sources during low wind periods. Transmission networks must already cope with outages of generation plant and daily changes in electrical demand. Systems with large wind capacity components may need more spinning reserve (plants operating at less than full load).
[Windmills are typically installed in favorable windy locations. In the image, wind power generators in Spain, near an Osborne bull.]
WIND POWER IN INDIA
The development of wind power in India began in the 1990s, and has significantly increased in the last few years. Although a relative newcomer to the wind industry compared with Denmark or the United States, India has the fifth largest installed wind power capacity in the world. In 2009-10 India's growth rate was highest among the other top four countries.
Initial cost for wind turbines is greater than that of conventional fossil fuel generators per MW installed. Noise is produced by the rotor blades. This is not normally an issue in the locations chosen for most wind farms and research by Sanford University shows that noise complaints for wind farms in the UK are almost non-existent.
[ Wind farm in Muppandal, Tamil Nadu.]
FUTURE
The Ministry of New and Renewable Energy (MNRE) has fixed a target of 10,500 MW between 2007–12, but an additional generation capacity of only about 6,000 MW might be available for commercial use by 2012.
The Ministry of New and Renewable Energy (MNRE) has announced a revised estimation of the potential wind resource in India from 49,130 MW assessed at 50m Hub heights to 102,788 MW assessed at 80m Hub height. The wind resource at higher Hub heights that are now prevailing is possibly even more.
BENEFITS
- Wind energy is an indirect form of solar energy and is free.
- It is a renewable energy source.
- There are no dangerous emissions.
- Wind power can be used in remote areas.
- Wind power can be used in conjunction with other renewable energy resources.
[Livestock ignore wind turbines, and continue to graze as they did before wind turbines were installed.]
----There is no energy crisis, only a crisis of ignorance. We simply must balance our demand for energy with our rapidly shrinking resources. By acting now we can control our future instead of letting the future control us.
BY
V.MAHESH (10H71A0218)
Categories:
TECHNICAL ARTICLES(session-2)
