wind energy,Which state is largest producer of wind energy in India?

WIND ENERGY

Uses of wind energy

Which state is largest producer of wind energy in India?

ans: Tamil Nadu

 

Wind energy is another potential source of energy. Winds are the motion of air caused by uneven heating of the earth's surface by the sun and rotation of the earth. It generates due to various global phenomena such as 'air-temperature difference' associated with different rates of solar heating Since the earth's surface is made up of land, desert, water, and forest areas, the surface absorbs the sun's radiation differently. Locally, the strong winds are created by sharp temperature difference be. Tween the land and the sea. Wind resources in India are tremendous. They are mainly located near the sea coasts. Its potential in India is estimated to be of 25 x 10 mW.

According to a news release from American Wind Energy Association the installed wind capacity in India in the year 2000 was 1167 mw and the wind energy production was 2.33 x 10 mWh. This is 0.6% of the total electricity production During the day, air above the land heats more quickly than air above water. The hot air over the land expands and rises, and the heavier, cooler air over a body of water rushes in to take its place, creating local winds. At night, the winds are reversed because air-cools more rapidly over land than over water. Similarly, the large atmospheric winds that circle the earth are created because land near the equator is heated more by the sun than land near the North and South Poles.

Today people can use wind energy to produce electricity. Wind is called a renewable energy source because we will never run out of it. Winds are natural phenomena in the atmosphere and have two different origins.

 

(1) Planetary winds are caused by daily rotation of earth around its polar axis and unequal temperature between Polar Regions and equatorial regions.

 

(2) Local Winds are caused by unequal and heating and cooling of ground surface of ocean 1 lake surfaces during day and night.

 WIND MACHINE FUNDAMENTALS

              Throughout history people have harnessed the wind. Over 5,000 years ago, the ancient Egyptians used wind power to sail their ships on the Nile River. Later people built windmills to grind their grain. The earliest known windmills were in Persia (the area now occupied by Iran). The early windmills looked like large paddle wheels. Centuries later, the people in Holland improved the windmill. They gave it propeller type blades and made it so it could be turned to face the wind. They have been used for pumping water or grinding grain. Windmills helped Holland become one of the world's most industrialized countries by the 17th century. Today, the windmill's modern equivalent — a wind turbine - can use the wind's energy to generate electricity.

 American colonists used windmills to grind wheat and corn, to pump water, and to cut wood at sawmills.

            In this century, people used windmills to generate electricity in rural areas that did not have electric service. When power lines began to transport electricity to rural areas in the 1930s, the electric windmills were used less and less.

          Then in the early 1970s, oil shortages created an environment eager for alternative energy sources, paving the way for the re-entry of the electric windmill on the American landscape.

           Today's wind machine is very different from yesterday's windmill. Along with the change in name have come changes in the use and technology of the windmill. While yesterday's machines were used primarily to convert the wind's kinetic energy into mechanical power to grind grain or pump water, today's wind machines are used primarily to generate electricity. Like old-fashioned windmills, today's wind machines still use blades to collect the wind's kinetic energy. Windmills work because they stow down the speed of the wind. The wind flows over the airfoil shaped blades causing lift, like the effect on airplane wings, causing them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.

               Modern wind machines are still wrestling with the problem of what to do when the wind isn't blowing. Large turbines are connected to the utility power network-some other type of generator picks up the load when there is no wind. Small turbines are often connected to diesel/electric generators or sometimes have a battery to store the extra energy they collect when the wind is blowing hard.

 

WIND POWER SYSTEMS

 

You usually stand in an open space to enjoy the wind. You know how wind originates. Moving air is wind. Since the wind has velocity it has kinetic energy. This is the energy of the wind. We shall see how the kinetic energy of the wind can be used to produce electricity. For that, we can use windmills. Windmills are devices, which work on wind. How dram the kinetic energy of the wind is made use of in windmills but 1 shall be looked into. We shall examine the working of a windmill. The important part of a windmill is a structure with large leaves, fixed at the top of a high tower.

        What will happen when wind blows on these leaves? You may have seen paper fans available at festival places, rotating when the wind blows. In a similar manner the speed 100 of leaves changes with the speed of the wind. What happens if the rotation of the windmill is given to the rotor of a generator? Rotor also rotates. Then electricity is obtained from the generator. What happens if the windmill is connected to a water pump? As the leaves of the windmill rotate pump Windmill farm. Works pumping out water.

                 Wind machines are just as efficient as coal plants. Wind plants convert 30 percent of the wind's kinetic energy into electricity. A coal-fired power plant converts about 30-35 percent of the heat energy) in coal into electricity. It is the capacity factor of wind plants that puts them a step behind other power plants. Capacity factor refers to the capability of a plant to produce energy. A plant with a 100 percent capacity rating would run all day, every day at full power. There would be no down time for repairs of refueling, an impossible dream for any plant. Wind plants have about a 25 percent capacity rating because wind machines only run when the wind is blowing around nine mph or more. In comparison, coal plants typically have a 75 percent capacity rating since they can run day or night, during any season of the year.

       One wind machine can produce 275-500 thousand kilowatt-hours (kWh) of electricity a year. That is enough electricity for about 50 homes per year.

       In this country, wind machines produce about three billion kWh of energy a year. Wind energy provides 0.12% of the nation's electricity, a very small amount. Still, that is enough electricity to serve

more than 300,000 households, as many as in a city the size of San Francisco or Washington, D.C. California produces more electricity from the wind than any other state of USA. It produces 98 percent of the electricity generated from the wind in the United States. Some 16.000 wind machines produce more than one percent of California's electricity. (This is about half as much electricity as is produced hy one nuclear power plant.) In the next 15 years, wind machines could produce five percent of California's electricity. The United States is the world's leading wind energy producer. The U.S. produces about half of the world's wind power. Other countries that have invested heavily in wind power research are Denmark, Japan, Germany, Sweden, The Netherlands, United Kingdom, and Italy. The American Wind Energy Association (AWEA) estimates wind energy could produce more than 10 percent of the nation's electricity within the next 30 years.

So, wind energy may be an important alternative energy source in the future, but it will not be the sole answer to our energy problems. We will still need other energy sources to meet our growing demand for electricity.

 

ECONOMIC ISSUES

 

On the economic front, there is a lot of good news for wind energy. First, a wind plant is far less expensive to construct than a conventional energy plant. Wind plants can simply add wind machines as electricity demand increases. Second, the cost of producing electricity from the wind has dropped dramatically in the last two decades. Electricity generated by the wind cost 30 cents per kWh in 1975, but now costs less than five cents per kWh. In comparison, new coal plants produce electricity at four cents per kWh. In the 1970s and 1980s, oil shocks and shortages pushed the development of alternative energy sources. In the 1990s, the push may come from something else, a renewed concem for the earth's environment.

                   We will use two terms to describe wind energy production: efficiency and capacity factor. Efficiency refers to how much useful energy (electricity, for example) we can get from an energy source. A -100 percent energy efficient machine would change all the energy put into the machine into useful energy. It would not waste any energy. (You should know there is no such thing as a 100 percent energy efficient machine. Some energy is always "lost” or wasted when one form of energy is converted to another. The "lost" energy is usually in the form of heat.)

SELECTION OF WIND MILL

Wind power plants, or wind farms or wind mill as they are sometimes called ,are clusters of wind machines used to produce electricity .A wind farm usually has hundreds of wind mechanism all shapes and size. Unlike coal or nuclear plants, public utility companies do not own most wind plants. Instead they are owned and operated by business people who sell the electricity produced on the wind farm to electric utilities. These private companies are known as Independent Power Producers.

Operating a wind power plant is not as simple as plunking down machines on a grassy field. Wind plant owners must carefully plan where to locate their machines. They must consider wind availability (how much the wind blows), local weather conditions, nearness to electrical transmission lines, and local zoning codes.

Wind plants also need a lot of land. One wind machine needs about two acres of land to call its own. A wind power plant takes up hundreds of acres. On the plus side, farmers can grow crops around the machines once they have been installed.

After a plant has been built, there are still maintenance costs. In some states, maintenance costs are offset by tax breaks given to power plants that use renewable energy sources. The Public Utility Regulatory Policies Act, or PURPA; also requires utility companies to purchase electricity from independent power producers at rates that are fair and nondiscriminatory.

RECENT DEVELOPMENTS

 

The present windmill technology is inadequate for the low wind speed regions in the plains. Special development projects in the following areas must be taken up so that wind energy can also be used in the low wind speed regions.

Artificial Winds. Generation of artificial winds to drive windmills by heating large surfaces with favorable thermodynamic properties is technically feasible. A project report has been prepared to heat a large surface in which case the resulting current (artificial wind) can drive turbines. The efforts needed to pursue the project in the form of money, manpower and time are huge.

 

Aero electric Plant. The low wind velocity in the plains can be augmented by the use of diffuser at intake to wind mills. Besides the propellers, Madras and Darrieus, there has been a plethora of designs for wind machines. One intriguing power plant design, called the aero electric plant, uses the flow up a tower that looks like a cooling tower. Its walls are heated by solar radiation. Since the walls are circular, the sun's rays need not be tracked as it changes position in the sky during the day. The heated walls, in turn, heat the inside air and a flow up the tower is established. This air flow is made to drive a number of air turbines located near the top of the tower. The driving pressure causing air flow is given by the well-known chimney effect.

            P. Carlson of California has proposed a slightly modified form in which, the interior air in a very tall tower would be cooled by pumping water to the top. The water evaporates in the low pressure air there, causing a downward flow of cooled air. The driving pressure can be calculated in a manner similar to that for wet cooling towers. A conceptual design of such a plant called for 2.4 km high, 300 m diameter tower located in a hot desert and 10 wind turbines surrounding the tower periphery at the bottom producing 2500 MW.

 

Low Wind Speed Turbines.

The turbines available in India and abroad are suitable for a rated wind speed of 3.5 m/s or more whereas low wind speed turbines for rated values of 1.5 - 2 m/s are needed for plain areas. Special efforts are, therefore, needed to develop cheap and simple rotors, which can cut in at low wind speeds available in the plains. The Sanctimonious rotor and American multiblade type windmills have opti-mum power coefficients at a ver low tip-speed and can therefore be used as starting point to develop windmills suitable for low wind speeds.