Dpurdy's List: Wind Energy

• In scientific terms, wind energy is the "force" of winds blowing across the earth’s surface ("Wind Energy").

  Wind is caused by uneven heating on the earth’s surface. The equator region receives more heat than say, Antarctica.
• That heat tries to move from hotter to colder regions. Wind energy was first harvested centuries ago, when early windmills were used to power millstones, pumps, and forges
• The amount of kinetic energy within Earth's atmosphere is equal to about 10,000 trillion kilowatt-hours.

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• The dirty secret of clean energy is that while generating it is getting easier, moving it to market is not.
• While the United States today gets barely 1 percent of its electricity from wind turbines, many experts are starting to think that figure could hit 20 percent.
• Achieving that would require moving large amounts of power over long distances, from the windy, lightly populated plains in the middle of the country to the coasts where many people live.
• “The windiest sites have not been built, because there is no way to move that electricity from there to the load centers,” he said
• The basic problem is that many transmission lines, and the connections between them, are simply too small for the amount of power companies would like to squeeze through them

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• Challenges

   

  Wind power must compete with conventional generation sources on a cost basis. Depending on how energetic a wind site is, the wind farm may or may not be cost competitive. 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.

   

  Good wind sites are often located in remote locations, far from cities where the electricity is needed. Transmission lines must be built to bring the electricity from the wind farm to the city.

   

  Wind resource development may compete with other uses for the land and those alternative uses may be more highly valued than electricity generation.

   

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

• Since early recorded history, people have been harnessing the energy of the wind. Wind energy propelled boats along the Nile River as early as 5000 B.C. By 200 B.C.,
• Commonly called wind turbines, these machines appeared in Denmark as early as 1890. In the 1940s the largest wind turbine of the time began operating on a Vermont hilltop known as Grandpa's Knob. This turbine, rated at 1.25 megawatts in winds of about 30 mph, fed electric power to the local utility network for several months during World War II.

• The United States has enough wind resources to generate electricity for every home and business in the nation. But not all areas are suitable for wind energy development.

• What is wind energy?

   

  Wind energy (or wind power) refers to the process by which wind turbines convert the movement of wind into electricity. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Humans use this wind flow for many purposes: sailing boats, pumping water, and also generating electricity. Wind turbines convert the kinetic energy of the moving wind into electricity.
• Birds and bats are occasionally killed in collisions with wind turbines. Like any form of development, wind projects can also negatively impact wildlife by altering habitat. Over the past two decades, the impact of wind development on birds has been greatly reduced by improvements in turbine design and particularly through improved project and turbine siting.

• The Sun heats our atmosphere unevenly,   so some patches become warmer than others.

   

  These warm patches of air rise, other air blows in   to replace them - and we feel a wind blowing.

   

  We can use the energy in the wind by building   a tall tower, with a large propellor on the top.

   

  The wind blows the propellor round, which turns a generator to   produce electricity.
• he best places for wind farms are in coastal   areas, at the tops of rounded hills, open plains and gaps in mountains   - places where the wind is strong and reliable. Some are offshore.
• The best places for wind farms are in coastal   areas, at the tops of rounded hills, open plains and gaps in mountains   - places where the wind is strong and reliable. Some are offshore.
• Advantages  

  Wind is free, wind farms need no fuel.       Produces no waste or greenhouse gases.       The land beneath can usually still be used for   farming
• Suitable areas for wind farms are often near the   coast, where land is expensive.
• Can be noisy. Wind generators have a reputation   for making a constant, low, "swooshing" noise day and   night, which can drive you nuts.
• Wind power is   renewable.   Winds will keep on blowing, it makes sense to use them.

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• Applications

    

  

  These wind turbines near Lamar, Colorado, are part of the 162-MW Colorado Green Wind Farm. Each turbine produces 1.5 megawatts of electricity.

    

  Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale (megawatt-sized) sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant. Several electricity providers today use wind plants to supply power to their customers.

• Wind is simply air in motion. It is caused by the uneven heating of the Earth's   surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. One example of this uneven heating can be found in the daily wind cycle.

• The Daily Wind Cycle

   

  During the day, the air above the land heats up more quickly than the air over   water. The warm air over the land expands and rises, and the heavier, cooler   air rushes in to take its place, creating wind. At night, the winds are reversed because the air cools more rapidly over land than over water.

   

  In the same way, the atmospheric winds that circle the earth are created because   the land near the Earth's equator is heated more by the sun than the land near   the North and South Poles.

   

  Wind Energy for Electricity Generation

     

  Today,   wind energy is mainly used to generate electricity. Wind is a renewable energy source because   the wind will blow as long as the sun shines

• Like old fashioned windmills, today’s wind machines (also called wind turbines) use blades to collect the wind’s kinetic energy. The wind flows  over the blades creating lift, like the effect on airplane wings,  which causes them to turn. The blades are connected to a drive shaft that turns an  electric generator to produce electricity.

   

  With the new wind machines, there is still the problem of what to do when  the wind isn't blowing. At those times, other types of power plants must be used to make electricity.

• Wind Production

    

  In 2010, wind turbines in the United States generated about 2% of total U.S. electricity generation. Although this is a small fraction of the Nation's total electricity production, it was equal to the annual electricity use of about 8.7 million households.
• Operating a wind power plant is not as simple as just building a windmill in a windy place. Wind plant owners must carefully plan where to locate their   machines. It is important to consider how fast and how much the wind blows at the site
• As a rule, wind speed increases with altitude and over open areas that have no windbreaks.   Good sites for wind plants are the tops of smooth, rounded hills, open plains  or shorelines, and mountain gaps that produce wind funneling.
• Conditions are well suited along much of the coasts of the United States to use wind energy. However, there are people who oppose putting turbines just offshore, near the coastlines, because they think the wind turbines will   spoil the view of the ocean. There is a plan to build an offshore  wind plant off the coast of Cape Cod, Massachusetts.
• Wind is a renewable energy source   that does not pollute, so some people see it as a good alternative to fossil   fuels.
• Since early recorded history, people have been harnessing the energy of the wind. Wind energy propelled boats along the Nile River as early as 5000 B.C.
• As late as the 1920s, Americans used small windmills to generate electricity   in rural areas without electric service. When power lines began to transport   electricity to rural areas in the 1930s, local windmills were used less and   less,
• In the early 1980s,    wind energy really took off in California, partly because of State policies that encouraged renewable energy sources.
• Wind is a clean source of energy, and overall, the use of wind for energy has fewer environmental impacts than using many other energy sources. Wind turbines (often called windmills) do not release emissions that pollute the air or water (with rare exceptions), and they do not require water for cooling. They may also reduce the amount of electricity generated from fossil fuels and therefore reduce the amount of air pollution, carbon dioxide emissions, and water use of fossil fuel power plants.
• Modern wind turbines are very large machines, and some people do not like their visual impact on the landscape.
• Some people do not like the sound that wind turbine blades make. Some types of wind turbines and wind projects cause bird and bat deaths. These deaths may contribute to declines in species that are also being affected by other human-related impacts.
• Most wind power projects on land also require service roads that add to their physical impact on the environment.

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•      

  Method	Cents/kW-h	Limitations and Externalities
  Wind Currently supplies approximately 1.4% of the global electricity demand. Wind is considered to be about 30% reliable.	4.0 - 6.0 Cents/kW-h	Wind is currently the only cost-effective alternative energy method, but has a number of problems. Wind farms are highly subject to lightning strikes, have high mechanical fatigue failure, are limited in size by hub stress, do not function well, if at all, under conditions of heavy rain, icing conditions or very cold climates, and are noisy and cannot be insulated for sound reduction due to their size and subsequent loss of wind velocity and power.
  Geothermal Currently supplies approximately 0.23% of the global electricity demand. Geothermal is considered 90-95% reliable.	4.5 - 30 Cents/kW-h	New low temperature conversion of heat to electricity is likely to make geothermal substantially more plausible (more shallow drilling possible) and less expensive. Generally, the bigger the plant, the less the cost and cost also depends upon the depth to be drilled and the temperature at the depth. The higher the temperature, the lower the cost per kwh. Cost may also be affect by where the drilling is to take place as concerns distance from the grid and another factor may be the permeability of the rock.
  Hydro Currently supplies around 19.9% of the global electricity demand. Hydro is considered to be 60% reliable.	5.1 - 11.3 Cents/kW-h	Hydro is currently the only source of renewable energy making substantive contributions to global energy demand. Hydro plants, however, can (obviously) only be built in a limited number of places, and can significantly damage aquatic ecosystems.
  Solar Currently supplies approximately 0.8% of the global electricity demand.	15 - 30 Cents/kW-h	Solar power has been expensive, but soon is expected to drop to as low as 3.5 cents/kW-h. Once the silicon shortage is remedied through alternative materials, a solar energy revolution is expected.
• Tide
  
  2 - 5 Cents/kW-h Blue Energy's tidal fence, engineered and ready for implementation, would provide a land bridge (road) while also generating electricity. Environmental impact is low. Tides are highly predictable.

• converts kinetic energy from the wind
• A wind turbine
• into mechanical energy
• The first electricity-generating wind turbine was a battery charging machine installed in July 1887 by Scottish academic James Blyth to light his holiday home in Marykirk, Scotland.

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