Most coal reserves exist in Eastern Europe and Asia, but the United States also has considerable reserves.
formed slowly over millions of years from the buried remains of ancient swamp plants.
The different forms of coal are peat ,lignite ,anthracite and bithumen
When the coal is burned, the pollutant sulfur dioxide is released into the atmosphere.
Crude oil or liquid petroleum, is a fossil fuel that is refined into many different energy products (e.g., gasoline, diesel fuel, jet fuel, heating oil).
Over 50 percent of the world's oil is found in the Middle East; sizeable additional reserves occur in North America
Despite its limited supply, oil is a relatively inexpensive fuel source
however, crude oil does cause environmental problems
It releases poisonus gases like carbon dioxide and sulphur dioxide into the atmosphere
Natural gas production is often a by-product of oil recovery
it is a mixture of gases, the most common being methane (CH4).
Natural gas is usually not contaminated with sulfur and is therefore the cleanest burning fossil fuel.
Natural gas is highly flammable and is odorless. The characteristic smell associated with natural gas is actually that of minute quantities of a smelly sulfur compound (ethyl mercaptan) which is added during refining to warn consumers of gas leaks.
Oil-Shale and Tar Sands
Oil shale is sedimentary rock with very fine pores that contain kerogen ,a carbon-based, waxy substance
Oil shale and tar sands are the least utilized fossil fuel sources
Tar sand is a type of sedimentary rock that is impregnated with a very thick crude oil
If tar sands are near the surface, they can be mined directly
The largest tar-sand deposit in the world is in Canada
In a nuclear power plant, the fission of uranium atoms in the reactor provides the heat to produce steam for
Heat is produced in a nuclear reactor when neutrons strike uranium atoms, causing them to split in a continuous chain reaction
nuclear energy is a clean and cheap source of energy
Nuclear fission does not produce atmospheric pollution or greenhouse gases
Nuclear power plant
Once considered, like nuclear power, ‘too cheap to meter’ but proved illusory because of the high cost of photovoltaic cells and due to limited demand.
The Solar Photo Voltaic (SPV) technology which enables the direct conversion of sun light into electricity can be used to run pumps, lights, refrigerators, TV sets, etc., and it has several distinct advantages, since it does not have moving parts, produces no noise or pollution, requires very little maintenance and can be installed anywhere.
A Solar Thermal Device, captures and transfers the heat energy available in solar radiation. The energy generated can be used for thermal applications in different temperature ranges. The heat can be used directly or further converted into mechanical or electrical energy.
The vast potential of energy of the seas and oceans which cover about three fourth of our planet, can make a significant contribution to meet the energy needs.
Ocean contains energy in the form of temperature gradients, waves and tides and ocean current, which can be used to generate electricity in an environment-friendly manner.
Technologies to harness tidal power, wave power and ocean thermal energy are being developed, to make it commercially viable.
Biomass is yet another important source of energy with potential to generate power to the extent of more than 50% of the country’s requirements.
Biomass can be obtained by raising energy farms or may be obtained from organic waste.
Biomass can be used in three ways – one in the form of gas through gasifiers for thermal applications, second in the form of methane gas to run gas engines and produce power and the third through combustion to produce steam and therby power.
Attempts to produce electricity with windmills date back to the beginning of the century.
Denmark erected the first batch of steel windmills specially built for generation of electricity.
The oil crisis of 1973 heralded a definite break through in harnessing wind energy.
The technology involves generation of electricity using turbines, which converts mechanical energy created by the rotation of blades into electrical energy, some times the mechanical energy from the mills is directly used for pumping water from well also.
The wind power programme in India was started during 1983-84 with the efforts of the Ministry of Non-Conventional Energy Sources. In India the total installed capacity from wind mills is 1612 MW, of which, Tamilnadu has an installed capacity of 858 MW as on 31.03.2002. Tamil Nadu is endowed with lengthy mountain ranges on its Western side with three prominent passes in its length. These are with wind-potentials: (1) Palghat Pass in Coimbatore District-1200 MW, (2) Shengottah Pass in Tirunelveli District-500MW (3) Aralvoymozhi Pass in Kanniyakumari District- 300 MW (Total potential-2000 MW). The mountainous areas close to Cumbum Valley are observed to be having high potential and, though coastal areas, central plains and hilly areas have been observed unsuitable for wind power projects, Rameshwaram is found suitable.
WHAT IS A WIND TURBINE?
It is a device which converts the kinetic energy of the wind to mechanical energy.
Different types of wind turbines
Chinese wind wheel
VAWT, Vertical Axis Wind Turbine
HAWT, Horizontal Axis Wind Turbine
The Danish concept
Grumman wind stream
Drag-type turbines The Persian windmill The Chinese wind wheel Savonious
Lift-type turbines VAWT, Darrieus
Lift-type turbines HAWT, American Multiblade
Lift-type turbines HAWT, The Danish Concept
The blades upwind the rotor
Constant speed on the rotor
Power output limitation
HAWT Horizontal-Axis Wind Turbines SMØLA
Wind Turbine components
Yaw system Yaw drive : Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind. Yaw motor : Powers the yaw drive.
Components of a horizontal axis wind turbine (gearbox, rotor shaft and brake assembly)
Nacelle Nacelle : The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
SOME IMPORTANT POINTS
WHAT HAPPENS IN A WIND TURBINE...
A rotor blade will stop giving lift thus rotating if the angle of attack is too steep .
Thus, rotor blade has to be twisted to attain an optimum angle of attack throughout the length.
It also helps stop the wind turbine in case of high wind speeds .
Normally wind turbines operate under wind speed of 33mph or 30 knots.
Thus, turbines which work at high efficiency at high wind speeds is useless.
Moreover, they need to waste excess energy to avoid damage to it.
It can be done safely by two ways
1.PITCH CONTROLLED WIND TURBINE
Turbines electronic controller checks the output several times a sec.
When power output becomes too high it pitches the blade(turns by an angle) out of the wind.
Conversely, it turns it back when the wind speed reduces.
Illustration of a pitch controlled wind turbine. (note:- the picture is exaggerated)
2.STALL CONTROLLED WIND TURBINES
These have rotor blades bolted into the hub at angle.
It is designed such that as soon as the wind speed becomeeeeees high turbulence is created.
Advantage over pitch controlled is that they have no moving part in the rotor blade.
3.OTHER POWER CONTROL SYSTEM
Some older wind turbines use flaps to control power just like an aeroplane.
Another technique is to yaw the turbine.
This is in practice for only small turbines(1 kW).
It is used to turn the turbine against the wind..
If the turbine is not perpendicular to the wind, then the power flowing is lower.
Almost all HAWT use forced yawing, i.e they use electric motors and gearbox.
Wind turbine running with yaw error are running with hiher fatigue loads.
It essential for turbines to stop automatically in case malfunction of components.
Thus, it is necessary to have an over speed safety system.
There are two types of braking:-
1.aerodynamic braking system
2.mechanical breaking system
1.Aerodynamic braking system
It consists of turning the rotor blades or tips about 90 0 about the longitudinal axis.
They are spring operated and thus work even in case of power failure.
They have a very gentle and secure way of stop the rotor thus avoiding the damage.
They are extremely safe .
MECHANICAL BRAKING SYSEM
they act as back-up for other mechanism.
They are a bit different than other turbines b'coz they have to handle changing mechanical torque.
They usually produce around 690 V, 50 or 60 Hz, 3 phase ac.
A ' wind farm is a group of wind turbines in the same location used for production of electric power.
Individual turbines are interconnected with a medium voltage (usually 34.5 kV) power collection system and communications network.
At a substation, this medium-voltage electrical current is increased in voltage with a transformer for connection to the high voltage transmission system
A large wind farm may consist of a few dozen to several hundred individual wind turbines, and cover an extended area of hundreds of square miles (square kilometers), but the land between the turbines may be used for agricultural or other purposes.
A wind farm may be located off-shore to take advantage of strong winds blowing over the surface of an ocean or lake.
Wind park effect
Effect on power grid
Types of Wind Farms
Onshore turbine installations in hilly or mountainous regions tend to be on ridgelines generally three kilometers or more inland from the nearest shoreline. This is done to exploit the so called topographic acceleration as the wind accelerates over a ridge.
Nearshore turbine installations are on land within three kilometers of a shoreline or on water within ten kilometers of land. These areas are good sites for turbine installation, because of wind produced by convection due to differential heating of land and sea each day. Wind speeds in these zones share the characteristics of both onshore and offshore wind, depending on the prevailing wind direction .
Offshore wind development zones are generally considered to be ten kilometers or more from land. Offshore wind turbines are less obtrusive than turbines on land, as their apparent size and noise is mitigated by distance.
In stormy areas with extended shallow continental shelves, turbines are practical to install.
Offshore installation is more expensive than onshore but this depends on the attributes of the site.
Airborne wind turbines would eliminate the cost of towers and might also be flown in high speed winds at high altitude. No such systems are in commercial operation.
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 US, a combination of domestic policy support for wind power and the rise of Suzlon (a leading global wind turbine manufacturer) have led India to become the country with the fifth largest installed wind power capacity in the world.
As of November 2008 the installed capacity of wind power in India was 9587.14 MW. It is estimated that 6,000 MW of additional wind power capacity will be installed in India by 2012. Wind power accounts for 6% of India's total installed power capacity, and it generates 1.6% of the country's power.
Despite the high installed capacity, the actual utilization of wind power in India is low because policy incentives are geared towards installation rather than operation of the plants. This is why only 1.6% of actual power production in India comes from wind although the installed capacity is 6%. The government is considering the addition of incentives for ongoing operation of installed wind power plants.
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 world’s energy potential for land based wind turbines Estimated energy output in kWh/kW from a wind turbine that are dimensioned for 11 m/s
Local Environmental Impacts
Wind energy also offers an opportunity to practice ecological restoration – Changes in land management next to wind farms may benefit the creation of new vegetation and animal habitats – Wind farms may act as refuge (new bird species appearing in the area) – Restoration of blanket bogs, peat and wetlands – both between and around the turbine s
Negative Impacts Bird Strikes
Noise Pollution Mechanical noise from gearboxes and generators– Aerodynamic noise from blades Depends on various factors: • layout of the wind farm • topography/shape of the land • speed and direction of the wind • background noise
22,994 lbs of Nitrogen Oxides
8,361 lbs of Sulphur
11,011,320 lbs of Carbon Dioxide
77,000 Tree Equivalent
1082 cars not driven
87 tankers full of petrol not used
11,615 barrels of oil saved
614 households not using electricity
128,064 trees grown
48 acres of forests preserved from deforestation
The positive impacts of Wind Energy production far out-weigh the negative impacts
Any impacts of wind energy should not be viewed in isolation.
They should be judged against the far more serious environmental impacts of producing electricity from other energy sources
State-wise Power Installed Capacity in India ( As on end of March 2008)
Global Installed wind power
Wind speed variable and unreliable
Wind turbines produce large amounts of noise pollution
Off-shore wind farms go some way to solving these problems, but they are expensive to build and maintain. It is cheaper to put more coal into an existing power station than to build a new wind farm
Wind speed vs. Number of hours of wind Related to variability is the short-term (hourly or daily) predictability of wind plant output. Like other electricity sources, wind energy must be "scheduled".
Annual Wind Power Generation (TWh) and total electricity consumption(TWh) for 10 largest countries. Rank Nation 2005 2006 2007 2008 Wind Power Capacity Factor % Total Power Wind Power Capacity Factor % Total Power Wind Power Capacity Factor % Total Power Wind Power Capacity Factor % Total Power 1 United States 17.8 22.2% 0.4% 4048.9 26.6 26.1% 0.7% 4058.1 34.5 23.4% 0.8% 4149.9 52.0 23.5% 1.3% 4108.6 2 Germany 27.2 16.9% 5.1% 533.7 30.7 17.0% 5.4% 569.9 38.5 19.7% 6.6% 584.9 3 Spain 20.7 23.5% 7.9% 260.7 22.9 22.4% 8.5% 268.8 27.2 20.5% 9.8% 276.8 31.4 21.7% 11.1% 282.1 4 China 1.9 17.2% 0.1% 2474.7 3.7 16.2% 0.1% 2834.4 5.6 10.6% 0.2% 3255.9 12.8 12.0% 0.4% 3426.8 5 India 6.3 16.2% 0.9% 679.2 7.6 13.8% 1.0% 726.7 14.7 21.0% 1.9% 774.7 6 Italy 2.3 15.3% 0.7% 330.4 3.0 16.1% 0.9% 337.5 4.0 16.7% 1.2% 339.9 7 France 0.9 13.6% 0.2% 482.4 2.2 16.0% 0.5% 478.4 4.0 18.6% 0.8% 480.3 5.6 18.8% 1.1% 494.5 8 United Kingdom 2.8 24.0% 0.7% 407.4 4.0 23.2% 1.0% 383.9 5.9 28.2% 1.5% 379.8 9 Denmark 6.6 24.0% 18.5% 35.7 6.1 22.2% 16.8% 36.4 7.2 26.3% 19.7% 36.4 6.9 24.9% 19.1% 36.2 10 Portugal 1.7 19.0% 3.6% 47.9 2.9 19.3% 5.9% 49.2 4.0 21.2% 8.0% 50.1 5.7 22.7% 11.3% 50.6
State-wise Wind Power Installed Capacity In India state As on 31.03.2006 As on 31.03.2007 Addition during 2006-7 Addition during 2007-08 Addition during 2008-09 Total Capacity Demons- tration Projects (MW) Private Sector Projects (MW) Total Capacity (MW) Demons- tration Projects (MW) Private Sector Projects (MW) Total Capacity (MW) (MW) (MW) (MW) till 30.11.08 (MW) Andhra Pradesh 5.4 115.6 121.0 7.800 113.54 121.34 0.8 0.0 0.0 122.45 gujarat 17.3 320.8 338.1 17.840 656.52 674.36 328.9 580.13 179.80 1432.71 Karnataka 7.1 577.5 584.6 7.075 837.95 845.02 264.7 187.0 173.10 1184.45 Kerala 2.0 0.0 2.0 2.125 0.23 2.35 0.0 8.7 12.50 23.00 Madhya Pradesh 0.6 39.7 40.3 0.590 56.00 56.59 17.4 69.25 0.00 187.69 maharashtra 8.4 992.9 1001.3 8.980 1471.3 1480.3 483.6 276.075 82.00 1837.85 Rajasthan 6.4 351.7 358.1 6.350 465.65 471.99 111.7 70.45 132.20 670.97 Tamil Nadu 19.4 2873.1 2892.5 19.355 3440.1 3459.4 565 391.90 250.30 4132.72 West Bengal 1.1 0.0 1.1 1.750 0.0 1.75 0.5 0.0 0.00 1.10 Others 1.6 0.0 1.6 1.6 0.0 1.6 0.0 0.0 0.00 3.20 Total (All ) 69.6 5271.0 5340.6 73.165 7041.2 7114.6 1773 1583.505 829.90 9587.14