Wind powered turbines are one of the most ancient forms of green energy sources on the planet. Wind turbines are designed to manufacture energy by converting the kinetic energy of the wind into mechanical energy, which is then either used directly (in the case of windmills, for example, which were used to make flour from grain, or to pump water for farming) or connected to an electrical generator that creates a direct current electrical output that can be used in a more general sense. In this publication we will be discussing the kind of wind turbines that output electrical energy, as this is more useful to us in our daily lives.Wind turbines are basically large windmills, with huge blades that rotate as a result of the wind and manufacture power from the conversion of the winds force. Wind turbines are manufactured from plastic, aluminium, steel and many other space age materials.Wind turbines can have several pronounced negative impacts on the environment. They are obviously very visible, and quite unsightly since they must be located in close proximity to windy, fairly open terrain to be useful - efforts to locate them out to sea have been met with a great deal of success. Wind Turbines also require a large amount of energy in their manufacture, energy which is fossil-based, and therefore it can take a substantial amount of time before they are positive in terms of total greenhouse gas emissions - this time can be anywhere from 2 to 5 years. Wind turbines are often associated with the mauling of rare species of birds that can be shredded as they pass between the turbine fans during migratory passages.With all of the downsides aside, wind turbines should be a choice when speaking about a broad plan for renewable power, in those areas that are well suited to them. Once constructed, wind turbines are very efficient in a larger sense - they generate electricity from a green, sustainable renewable resource, without the social or environmental costs that we incur with the burning of fossil fuels - there is no need to mine for fuel or to transport it - there arent any greenhouse gas pollutants created, and no need to contain, process, or to deal with toxic wastes.At the small end of the scale, turbines can be as tiny as five feet in diameter and are capable of only a few hundred watts. On the high end of the spectrum, turbines can be as huge as three hundred feet in diameter and are capable of generating 2 to 4 megawatts of power.Similar to photovoltaic solar power generation, there might be rebates available to induce construction, and energy in excess of that which we are consuming can be sold back to the utility company.Wind velocity is affected by terrain and increases with altitude, so wind turbines are generally installed on large towers. In a typical application, the wind turbine sits atop a tall tower and generates direct current which is used to charge batteries - this stored charge is ultimately utilized by routing it through an inverter which converts the direct current energy into high voltage AC electricity for use in household applications. By concentrating numerous turbines into wind farms a massive amount of power can be stored and utilized, perhaps for a whole city or town.Because the wind doesnt blow all of the time in many areas, wind turbines are used as adjuncts in hybrid configurations with many different technologies like photovoltaic solar panels, and diesel generators to provide a constant source of energy.Contrary to coal power stations, wind turbines are clean and green - they do not make the carbon dioxide emissions that are thought to be causing global warming or the sulfur dioxide emissions that cause acid rain. Todays turbines are divided into 2 categories, namely horizontal turbines and vertica axis turbines. Modern horizontal axis wind machines are actually superior at capturing the wind than vertical axis machines given the same amount of swept blade area (which is the diameter of the circle traced by the tip of the rotor blades).