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America’s hungriest wind and solar power users: big companies

Major U.S. corporations such as Wal-Mart Stores Inc (WMT.N) and General Motors Co (GM.N) have become some of America’s biggest buyers of renewable energy, driving growth in an industry seen as key to helping the United States cut carbon emissions.

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How Wind Turbines Operate?

In contrast to the windmills common in the nineteenth century, a modern power generating wind turbine is designed to produce high quality, network frequency electricity whenever enough wind is available. Wind turbines can operate continuously, unattended and with low maintenance with some 120,000 hours of active operation in a design life of 20 years. By comparison, a typical car engine has a design lifetime of the order of 6,000 hours.

The rotors of modern wind turbines generally consist of three blades, with their speed and power controlled by either stall or pitch regulation. Stall regulation involves controlling the mechanical rotation of the blades, pitch regulation (now more commonly used) involves changing the angle of the blades themselves. Rotor blades are manufactured from composite materials using fibreglass and polyester or fibreglass and epoxy, sometimes in combination with wood and carbon.

Energy captured by the steadily rotating blades is transferred to an electrical generator via a gearbox and drive train. Alternatively, the generator can be coupled directly to the rotor in a direct drive`s arrangement. Turbines able to operate at varying speeds are increasingly common, a characteristic which improves compatibility with

the electricity grid. The gearbox, generator and other control equipment are housed within a protective nacelle.

Tubular towers supporting the nacelle and rotor are usually made of steel, and taper from their base to the top. The entire nacelle and rotor are designed to move round, or yaw, in order to face the prevailing wind.

Wind resources and monitoring

The wind resource is the fuel for a wind power station, and just small changes have large impact on the commercial value of a farm. Every time the average wind speed doubles, the

power in the wind increases by a factor of eight, so even small changes in average speed can produce large changes in performance. If the average wind speed at a given site increases from 6 metres per second (m/s) to 10 m/s, for example, the amount of energy produced by a wind farm will increase by over 130%. Detailed and reliable information about how strongly, from which direction and how regularly the wind blows, is therefore vital for any prospective development.

At a national and regional level, European wind atlases have been produced which record the wind speed to be expected in particular areas. For specific sites, more detailed assessment is required using data from nearby weather stations and specialist computer software to model the wind resource. Finally, site specific measurements are carried out using an anemometry mast on which a number of anemometers measure the wind speed and direction at different heights above ground.

Overall, the exploitable onshore wind resource for the European Union (EU-25) is conservatively estimated to be capable of generating an output of 600 Terawatt hours (TWh). The wind resource in offshore waters has been assessed at up to 3,000 TWh. This alone would exceed Europe`s entire current electricity consumption.

Wind farms

A number of constraints affect the siting of a cluster of wind turbines, usually described as a

wind farm or park. These include land ownership, positioning in relation to buildings and roads, and avoidance of sites of special environmental importance. Once these constraints have been determined, the layout of the wind turbines themselves can be planned. The overall aim is to maximise electricity production whilst minimizing infrastructure, operation and maintenance (O&M) costs, and environmental impacts. Specialist software has been developed to produce visualizations of how the turbines will appear in the landscape, enabling developers and planners to choose the best visual impact solutions before the project is constructed.

Apart from the turbines themselves, the other principal components of a wind farm are the foundations to support the turbine towers, access roads and the infrastructure to export the electrical output to the grid network. A 10 MW wind farm can easily be constructed within two months, producing enough power to meet the consumption of over 5,000 average European households.

Once operating, a wind farm can be monitored and controlled remotely. A mobile

team carries out maintenance work, with roughly two personnel for every 20 to 30 turbines. Typical maintenance time for a modern wind turbine is about 40 hours per year. Wind farms can vary in size from a few megawatts up to the largest so far – 300 MW in the western United States.

The advantages of wind power

� Low cost can be competitive with nuclear, coal and gas on a level

� playing field

� The fuel is free, abundant and inexhaustible

� Clean energy – no resulting carbon dioxide emissions

� Provides a hedge against fuel price volatility

� Security of supply – avoids reliance on imported fuels

� Modular and rapid to install

� Provides bulk power equivalent to conventional sources

� Land friendly – agricultural/industrial activity can continue around it.

Tilos, Greece: the first island in the Med to run entirely on wind and solar power

Tiny Tilos, in the Dodecanese, is a pioneering nature reserve. Now, Greece’s ‘green island’ is set to be powered by renewable energy

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Harnessing Wind Power: Viable And Effective

With the cost (and pollution levels) of traditional energy sources such as burning coal and other combustible resources being extremely high, countries are obliged by themselves to look at other, more renewable energy sources to meet their needs. Energy from the wind is cited to solve this current energy shortage trends.

To get energy from wind, we must focus on a concept known as kinetic energy. Whereas many wind projects have been turned down in many areas such as the Cape Cod wind energy project other regions are embracing such technologies.

Equipment Used In Wind Power Generation

Turbines turn with the wind, and then this turning produces enough momentum to charge energy storage cells (such as batteries). While shafts actually create the energy that is then stored or converted into electricity.

Advantages Of Harnessing The Wind Energy:

1. Not only is wind power a renewable energy, but like other renewable energies it gives off no harmful greenhouse gases while being operated – no methane, no carbon dioxide.
2. Fuel costs and global warming are becoming a bigger concern for people in their daily lives, energy is environment friendly.
3. Another advantage of this wind energy is that it displaces carbon dioxide emissions totaling 15 million tons each year.

Some Reason For Harnessing wind Energy:

1. First, it produces no pollution or greenhouse gases.
2. Second, it is renewable and will last for as long as our son about another four billion years.
3. The bigger issue is getting them to produce enough energy at as low a price as possible to make them a viable energy production platform.

Generating Wind Power From Wind:

The process is viable, but we must accept it and pursue better technology to wring the most out of the huffing and puffing of Mother Nature. This process is natural and simple, but produces a monstrous amount of energy. We then convert it into usable electricity by catching it with wind turbines.

Some Tips For Generating Wind Energy:

1. The advantage of offshore wind farms has to do with the frequency and generation of winds.
2. On top of all of this, placing wind farms in the ocean avoids the cost of buying pricey space on land.
3. Given this situation, ideal locations for wind farms are often along shorelines or in valleys funneling winds from the shore.

Some Countries Harnessing Wind Energy:

1. China is also beginning to invest large amounts of resources in wind farms as its energy needs grow.
2. There are other countries on the continent of Africa that are trying pilot wind energy projects, both on large scales and small, home based turbine scales.
3. One place where African wind energy is being used in large amounts is found in South Africa, in Cape Town.