Johnson.Plummer+Windpower+Fall+2010

= **Wind Power** =

**by Brooke Johnson and Christopher Plummer**


** The problem at hand is one with effects that cannot be reversed but only slowed. Global warming became reality after the harsh effects of it were blatantly obvious. The warming itself is caused by deforestation and the burning of fossil fuels among other things. These contributors are increasing the amount of CO2 in the atmosphere which is negatively affecting our climate. Although the temperature change is only apparent on a large scale such as a hundred years, the problems it is creating can be seen in our day to day lives. **

Few resources on this planet are limitless, and fossil fuel is certainly not one of them. Fossil fuels are hydrocarbons such as coal, oil, and natural gas sourced from the organic remains of prehistoric organisms in the ground. Fossil fuels are mainly used for powering cars, heating homes, and as a source of electricity. These are non-renewable resources, which are expected to be completely consumed in the next 30 years. Luckily for us, new energy sources are created each day to try to replace these sources.

Some of the newest and most popular sources for alternative energy are the sun. ethanol, wind, and water. Solar panels collect solar radiation from the sun and actively convert that energy to electricity. The energy generated from photons striking the surface of the solar panel allows electrons to be knocked out of their obits and released. Electric fields in the solar cells pull these free electrons in a directional current, from which metal contacts in the solar cell can generate electricity. Ethanol is a natural alcohol which is used as an additive to gasoline. The most common type of ethanol is grain, which is extracted from grains and corn and used to create energy. Windmills use wind, which is a free and renewable resource. Ethe energy produced by these can completely eliminate the cost of electricity and whatever energy is not used can be sold back to willing companies. Hydro power is an energy form also created from renewable resource, which uses the force of water in rivers and tides to create energy. Out of all of these sources of energy, it seems as though wind is the most effective. Not only is wind free, but it can be found anywhere on the planet and there is an unlimited supply.

media type="file" key="How Wind Turbines Generate Electricity.flv" width="360" height="270" align="center"

To create wind power, wind generators are used to capture the kinetic energy of wind. Although wind power is only accountable for less than one percent of global energy consumption, it is becoming more and more popular worldwide. The best way to think about how wind is used to create electricity is to think of the air as a fluid. Even though air is not visible to the eye, it is a fluid just like any other, except its particles are in the form of gases instead of liquid. As air becomes stronger and moves quickly in the form of wind, it causes those gas particles to move quickly. This motion, which can be captured is called kinetic energy. This is similar to the way water is captured by turbines in hydroelectric dams. Wind-electric turbines however use their specially designed blades to capture the winds kinetic energy. These two turbines are virtually identical otherwise in the way they convert the energy into electricity. As the blades of the turbine capture all of the winds kinetic energy and begin to move, a shaft inside the wind mill begins to spin which leads from the hub of the rotor to a generator.



Electricity is created by the generator as it collects the rational energy. Harvesting wind energy basically comes down to transferring energy from one medium to another. The sun is what causes the wind power. As the sun heats up different areas of land, air masses around that land absorb the heat. When the air heats up to a certain temperature, air that is hotter in temperature quickly rises because its given volume is less than the same volume of air that is colder. The hotter and faster moving air particles are able to exert a higher pressure than the colder air particles which means that fewer of the hotter particles are needed to maintain the normal air pressure at a given elevation. As soon as the lighter hot air begins to rise suddenly, the cooler air quickly moves in to fill the gaps. The air that is moving in quickly to fill the gaps is called wind. By placing a rotor blade in the path of the wind, the wind will transfer some of its energy to the blade giving the blade motion. This is the process by which a wind turbine captures the winds energy. This process is very similar to the way in which a sail captures wind to push a sailboat. As moving air pushes the barrier of a sail, it causes the boat to move; thus the wind in this case has transferred its own energy of motion to the sailboat.



Wind turbines in the simplest design consist of three main parts which are rotor blades, shaft, and a generator. The rotor blades are best thought of as the sails of the whole system because they act as the barriers to the wind. New more modern designs of blades tend to go beyond the barrier method. Connecting to the center of the rotor of the wind mill is the shaft. As the wind causes the rotor to move the shaft spins along with it. The rotor transfers its mechanical and rotational energy to the shaft which in turn enters the electrical generator on the other end. The generator at its most basic is actually a simple device. It produces electrical voltage by using the properties of electromagnetic induction. To put it simply voltage is electrical pressure. Voltage is also the force that moves electricity or electrical current from one point to another. By creating voltage the generator is in effect making current. Simple generators consist primarily of magnets and a conductor. A coiled wire is normally what makes up the conductor. The generator has a shaft that connects to an assembly of permanent magnets that completely surrounds the coil of wire. As the rotor spins the shaft it causes the shaft to spin the whole assembly of magnets which in turn generates the voltage in the coil of wire. Electrical current is driven by the voltage, typically AC power, and is run out through power lines set up for distribution.



Wind turbines do not offer a panacea that will replace traditional sources of electricity- those monumental shoes will take a few more years to fill. At best windmills can provide around 20% of overall electricity production. However, wind power provides a an unusual source of cost-effective, clean electricity in an increasingly energy-hungry world.