The planet's terrain, water bodies, and vegetation then affect the wind flow patterns. With the invention of wind turbines, we can now harness the wind's energy and use it instead of purchasing electricity from the utility companies that are derived from non-renewable sources.
The easiest way to understand how wind turbines work is to think of a fan operating in reverse - rather than electricity spinning the blades and thus generating wind, the wind spins the blades, thereby generating electricity.
Breaking it down to it's simplest components, a wind turbine operates as follows:
- the wind turns the blades
- the blades spin a shaft
- the shaft connects to a generator
- the generator produces electricity
There are two basic types of wind turbine:
- horizontal axis wind turbines: the kind most commonly in use today and the focus of U.S.
- Department of Energy research on wind power, these come in two varieties -
- 2-blade horizontal axis turbines spin downwind
- 3-blade horizontal axis turbines spin upwind
- vertical axis wind turbines
In an innovative advancement known as hybrid wind systems, these smaller turbines are also being used in combination with solar (photovoltaic) systems, rechargeable deep-cycle batteries, and diesel generators to provide storable, on-demand power in more remote, off-the-grid places.
In most residential situations, a wind turbine is used as a supplemental source of power in combination with local, on-the-grid, utility power. There is something called a cut-in speed (7-10 miles per hour), below which the wind turbine will cease to provide an output, and the utility grid provides the structure's power. Above the cut-in speed, the wind turbine kicks in and the grid power supply is proportionately reduced (depending on the structure's energy draw at the given moment).
If the output produced by the wind turbine exceeds the draw from the structure (and/or storage devices, like batteries), the excess power is then sold back to the pubic utility company. Use of wind energy can reduce a residence's energy costs by, on average, 50-90%, though these numbers are influenced by a variety of factors and, as such, can fluctuate greatly.
In a typical residence that uses under 10,000 kilowatt hours per year of electric power, a 5-15 kilowatt wind turbine should more than suffice. This type of system can run anywhere from $6,000-$22,000 to install, depending on a variety of factors, including: its size, your intended application, and any service contracts entered into with the manufacturer.
Being that certain situations (such as in the city) make personal wind power use an unviable option, a general rule of thumb is to consider installing your own wind power system if and only if you pay at least 10 cents per kilowatt hour and your location's average wind speeds exceed 10 miles per hour.
The larger wind turbines have capacities upwards of 50 kilowatts, running these days into the several-megawatt range. These windmills, known as utility scale turbines, can be grouped together and connected to central lines for transmitting and distributing in bulk to the local utility grids that, in turn, sell that power to homes and businesses across the land. These are called wind power plants or wind farms.
What is exactly meant by wind power?
Solar radiations emit a type of energy, which result in creation of wind. The sun heats up the earth's terrains in uneven amounts. Such unequal heating is caused by the rotational motions of earth, the unevenness of earth's surface, the varying propensities of heat absorption at different levels of the atmosphere, the vegetation types as well as the presence of the water bodies of the earth. As a consequence, some parts of earth remain naturally hotter than certain other regions. An easy example in this context is the large and fixed temperature difference that exists between the equatorial areas and the freezing polar regions.
In the warmer parts of earth, the air is less dense, and as such, it starts to rise. This results in the creation of an empty space in their place. This space soon gets occupied by the cooler air that rushes in from the cold regions that lie nearby. This motion of air, called wind, generates a form of energy (kinetic energy). Modern methods are used to tap and harness this kinetic energy, in order to convert the latter into wind energy. Wind power refers to the techniques of the practical usage of wind energy for the production of electricity and such other reusable forms of output. Since wind power is extensively being use today, let us look into the issue of wind power cost in greater detail.
What are the expenses of using wind power?
The rate of growth of the wind energy systems has indeed been very rapid over the last few years. As a result, the wind power cost levels have fallen by around 80 per cent since the days when utility-grade wind energy units were used. This huge reduction in costs has been achieved within the past couple of decades. The current level of wind power cost, which currently stands at five cents per kilowatt-hour, used to be as high as thirty cents per kilowatt-hour in the 1980s, when wind power systems made their initial appearance. The more suitably designed machines, the advanced levels of technologies, and the overall ideal nature of the sites chosen for setting up the large-scale wind energy units have all contributed to this magical fall in the wind power cost amounts.
Wind energy systems are likely to sustain over the long run as well. Unlike the previously used fossil fuel plants, which frequently faced bottlenecks in fuel supply, wind based units make us of an abundantly available fuel resource (viz., the wind itself). Thus, more and more countries are shifting from conventional power generation plants to using wind energy systems, since wind is free to obtain, and is always readily available. The wind energy units are extremely environment-friendly in nature as well, much more so than the fossil fuel systems.
As a result, air pollution goes down by a significant amount, making the choice of wind energy resources indeed a wise decision. Immense economic advantages can also accrue from the usage wind energy plants. The plants take up only a little of the total land area that is taken on lease for their installation, by farmers. Thus, farming activities can be continued without any problems on the remainder of the land. Hence, farmers ensure two simultaneous source of long term income for themselves - from farming and from the sale proceeds of the produced electrical power on their lands.
How much wind energy the system would be able to generate depends crucially on the velocity of wind in that area. Hence, choosing a proper site for these wind energy systems is of the essence. In particular, places that have wind flowing at speeds in excess of 5 to 7 peters per second are considered to be ideal for the installation of these units.
Slashing the cost of wind power
Wind power plant costs can be slashed by large amounts, if proper financial management is done for them. Cost of wind power falls heavily in cases where a gas power plant and a wind power unit are acquired on identical terms. The ownership of the wind energy system by a utility service, as opposed to individual ownership, can also pull down costs by large amounts. Let us consider an example: A 50 MW wind power plant, when owned by individuals (like wind developers) can yield power at the cost of 5 cents per kilowatt-hour. However, reduction of wind power cost, to the tune of 30 per cent (lowering it to around 3.5 cents per kilowatt-hour) is possible by using the same wind power plant, if the latter is in the hands of investor-owned utilities (IOUs)