My wife and I frequently drive across the country to visit family. On a recent trip as we passed a large wind farm in northern
What is wind energy used for? Wind energy today is used to produce electricity. There are a few other uses for wind energy, but in the modern world, those big wind turbines you may see while traveling cross country are used to produce electricity.
Related: Is Wind Energy Effective?
Just fifty years ago, wind turbines were used mostly to pump water. These wind pumps were much smaller but are common to be seen on farms throughout the great plains of America. And, for hundreds of years the Dutch also used a much larger type of wind turbine for pumping water.
In the United States (and in most of the ‘developed’ world) we take the availability of consistent, constant, and stable electricity as an expectation. In fact, not having a stable electric grid is the very definition of an undeveloped area. Electricity can be used to heat and cool our buildings, provide our lighting, power our computers, run our power tools, pump our water, and power every other modern contrivance. The major use of electricity is to provide cooling and refrigeration. The use of an air conditioner is the greatest electric expense in most American homes.
How does Wind get its Power?
Wind is the invisible motion of air molecules. Wind is produced by several actions, mostly of the rotation of the Earth and the heating of the Earth by the Sun. Since the Earth constantly turns (or spins) on its axis in relation to the Sun, one side is always in the shade, and the other in the sunshine. The sun heats the side facing it, while the side of the Earth opposite the sun cools. This imbalance in heating causes warm air to expand—moving toward the cooler parts. That motion is wind!
Landforms, like mountains, oceans, deserts, valleys, trees, ice, buildings, and other obstacles may gently shift the wind from place to place as well as even the colors of the ground might affect the wind. White ice is more likely to reflect the sunlight, just as dark blue oceans may absorb more energy from the sun. These differences in color, texture, motion and velocity all can have an impact on the movement of air molecules. The science of studying the earth-wind reaction, particularly in how it changes weather patterns, is called meteorology.
Who Decides Where Wind Turbines Will Be Built?
Modern wind turbines are very expensive. Therefore, putting the wind turbine in the best spot is a specialized science. The need to find the very best spot is so new a field of study, that there isn’t yet a good name for the occupation of the person responsible, but it fits generally in the term of a “wind farm developer.” Usually this isn’t a single person, but a team of experts who find the right site, obtain the funding, plan the project, and construct the actual wind farm. Those who work in this field are called wind farm developers.
Wind turbines can be erected as a single turbine, but due to the economies of scale of construction and operation of a wind farm, they are often built as a group of 40 to 100 turbines in one area. The first step taken is to erect an anemometer (this is just a machine which measures the wind speed and direction over a period of years) to determine if the area has enough wind at the required speed and strength to support a wind turbine. Each turbine (that is each individual electric generating device, with its blades, generator, and equipment) costs about $1,000,000.00. It may take another half-a-million dollars to construct, install, and operate the wind turbine.
Why are Wind Turbines built in Farms?
By putting several wind turbines in one area, the cost of construction, installation, and operation can be reduced on a per-turbine basis, which is why they are often built in “farms” of several turbines in one area.
So, imagine that the construction crane that will be used to build a wind turbine costs $20,000.00 a day to rent. The wind farm developer may pay not only for the day-rate, but the transportation costs to the site. Once the crane is in the vicinity, the cost of moving it, and the day-rate cost of moving it from one turbine to the next is relatively low. So, if building just one turbine, it may cost 10-days to transport the crane to the site, erect it, and build the one turbine, costing the developer $200,000.00 to erect his one turbine. However, if you are building forty turbines, the number of days the wind farm developer is paying for the crane may be only fifty days for the entire project. This would make the cost per turbine for the crane rental to average only $25,000.00 per turbine. This “economy of scale” produces the incentive to build multiple turbines in a single “wind farm.”
Other “installation” costs are similarly amortized over multiple turbines. An operating cost is equally spread over a group of wind turbines. A single operator can monitor as many as fifty turbines—monitoring them for production, maintenance, flaws, weather and the like. But, to monitor a single turbine also requires one operations monitor.
Wind turbines can be shut off when wind speeds get too high; they need to be. In a heavy storm, the wind may exceed the operating capacity of the wind turbine. So, when extreme conditions exist (think of a tornado, hurricane, lightning storm or strong front come through an area) the wind turbines may need to be shut off to protect them from damage. Since wind turbines may need to be shut off, someone must make the decision as to when to shut them off, for how long, and when to re-start them. A single wind turbine needs this analysis done just as an entire wind farm might. It is easier to justify this expense—to amortize the operating cost—over a wind farm, than an individual turbine.
How Is Electricity Made From Wind?
Electricity is generated by passing a coil of metal through a magnetic field. Typically, the metal is a coil of tightly wrapped copper wire. In early experiments with electricity, it was found that with enough coils of copper wire, and spinning the coils between magnets, electricity could be generated. US Patent number 132 was for the invention of a working electric generator. The very first electric motors were developed in the 1830’s.
Ultimately what was needed was a way to spin either the magnets through the coils of wire or spin the coils of wire through a stationary magnetic field. The key was obtaining the necessary power to spin the contraption. Flowing water worked as a power source (this is called hydro-electric power) as could an internal combustion engine, or the turning of a windmill.
Today, we use several differing sources of primary power to create electric power. Wind is just one of those methods. The most common method is the burning of fossil fuels (coal and natural gas which together account for 62% of all electricity produced in the US in 2017) followed by nuclear power (20%) and the remaining is produced by renewable energy sources (hydroelectricity 7.5%; wind 6.3%; biomass 1.6%, solar 1.3%; and geothermal 0.4%).
What is Electricity?
Electricity is the movement of electrons. It is how we transport the power from one place to another. The electricity is created at some distance from where it is used, typically. The flow of electrons begins as the primary power source is used to turn the electric generator, which is the coil of wire turning through very large magnets.
The electrons (now moving as the force we call electricity) move through metal wires across a network of power lines to your home where you take that flow of electrons and use it in, say your blender, where a small electric motor uses the flow of electrons to turn a coil of wire through a magnet, reversing the process, and spinning the blades on your blender. The first translating device that move from the motion of the wind to create electricity is called an electric generator. The second translating device, which takes the electricity, and re-converts it into useful energy, is called an electric motor.
Those two devices—the electric generator, and the electric motor—are essentially the same type of device. They consist of the electric coil, and the magnets. One is used to get the electrons moving, the other to take the moving electrons and return them into motion.
Now, wind power generates only a small portion of the electricity used in the United States. However, as time goes on, it will produce a larger percentage of the power, just due to its low cost.
As long as fossil fuels are relatively inexpensive, as they currently are, those inexpensive fossil fuels will be used. But as our naturally occurring fossil fuel resources are consumed at a greater rate than they are generated, the time will come when the alternative fuels—wind, water, and direct sunlight—will be used more often.
Wind and water power are both indirectly forms of solar power. That is, it is the sun which heats the earth in such a way that wind is created. It is the heat of the sun which causes the water in the oceans to evaporate, and fall on the land, creating rivers and streams which flow toward the ocean. Damming those rivers and streams allows us to use the force of flowing water to spin electric generators.
If you’re serious about learning more about wind energy, I recommend the Wind Energy Handbook on Amazon. This book is great for both students and professionals, and it holds invaluable information on the subject of wind power.