Wind turbines work on a straightforward concept. Two or three propeller-like blades spin around a rotor as a result of the wind’s energy. The rotor is attached to the main shaft, which generates power by spinning a generator.
What causes the blades of wind turbines to spin?
act in the same way as an airplane wing. A pocket of low-pressure air formed on one side of the blade when the wind blows. The blade is subsequently drawn toward the low-pressure air pocket, forcing the rotor to spin. This is referred to as lift. The lift is substantially stronger than the drag, which is the force of the wind against the blade’s front side. The rotor spins like a propeller due to the combination of lift and drag.
Do windmills begin spinning on their own?
Off the shores of 11 European countries, more than 2,300 wind turbines are spinning and producing energy. The North and Irish seas are home to a huge number of these turbines. One explanation for this is that the winds that blow across such bodies of water are not only strong, but also persistent.
Wind energy developers are looking at the North Carolina coast as a potential location for wind farms for the same reason. But this raises the question of how much wind a wind farm, or at the very least a wind turbine, requires.
It should come as no surprise that, just as the wind changes frequently, wind turbines are designed to operate in a wide range of wind conditions, therefore the answer fluctuates.
Upwind turbines face the wind, and downwind turbines face the opposite direction. Wind turbines of the new generation can operate at lower wind speeds, typically about five miles per hour. These turbines, on the other hand, are often smaller, produce less electricity, and are not intended to resist higher wind ranges.
Winds of seven to nine miles per hour are usually enough to get most large-scale wind turbines turning. Their greatest speed is roughly 50-55 mph, which is their maximum safe speed. To prevent damage to the blades, large-scale wind turbines usually incorporate a braking system that kicks in approximately 55 mph.
Many industrial-scale wind turbines, ironically, require an electric ‘kick-start’ to get started. That’s what gets the blades to start turning despite their inertia.
You might believe that when the blades turn, electricity is produced.
The blades are attached to a shaft that rotates at a rate of 30 to 60 times per minute. The shaft is then connected to a gear box, which boosts the rotation speed from 1000 to 1800 revolutions per minute, which is the required speed for most generators to generate power.
Of course, the amount of electricity generated by a wind turbine is determined by the turbine’s size, commonly known as its power rating, and the speed of the wind at the turbine’s position. The power rating of wind turbines typically ranges from 250 watts (enough to charge a battery) to 10 kilowatts (enough to power a house) to six megawatts (enough to power more than 1600 houses).
Frank Graff is a UNC-TV producer/reporter who focuses on North Carolina Scientific Now, a weekly science series that began airing on Wednesdays in August 2013 as part of UNC-North TV’s Carolina Now. Frank will share additional information about his tales through our North Carolina Science Now Reporter’s Blog, in addition to producing these special pieces.
When there is no wind, how do windmills function?
It works by pointing a device into the wind (typically two or three blades) and allowing the wind’s energy to spin the blades. The rotor to which the blades are linked spins gears that are connected to an electrical generator while the blades spin. From the slow-moving blades to the fast-moving generator engine, the gears increase the spin rate. The electricity is sent down the tower to be used by the generator.
My post, How Do Wind Turbines Work, explains everything and includes an infographic to assist visualize the process.
Because the blades must always face the wind, large-scale wind turbines have wind sensing devices and computers that turn the turbine to face the wind.
Please see my factual post on How Does a Wind Turbine Generate Electricity for more information on how a wind turbine works.
What’s the deal with some wind turbines that aren’t spinning?
Why don’t the turbines spin all of the time? The most common reason for turbines stopping to spin is that the wind is not blowing fast enough. To operate, most wind turbines require a sustained wind speed of 9 MPH or higher. Turbines will also be shut down for scheduled maintenance or repairs.
What is the lifespan of a wind turbine?
A modern wind turbine of acceptable quality will typically last 20 years, however this can be extended to 25 years or beyond depending on environmental circumstances and proper maintenance practices. However, as the structure ages, the maintenance expenditures will rise.
What is the mechanism through which windmills pump water?
- The windmill wheel’s blades, also known as sails, capture the wind and turn the rotor.
- The hub assembly is connected to a geared mechanism that translates rotary motion into up-and-down motion.
- A lengthy sucker rod, also known as a pump rod, is driven up and down within a pipe in the well by this up-and-down motion.
- A cylinder with a sealed plunger running up and down inside is attached to the pipe’s end, forcing the water up the pipe.
- Because a check valve in the bottom of the pipe prevents the water from being pushed out on the downstroke, the water is driven up the pipe on the following upstroke.
What is the annual revenue of a wind turbine?
The output of a wind turbine is determined by the size of the turbine and the speed of the wind through the rotor. An average onshore wind turbine with a capacity of 2.53 MW may generate more than 6 million kWh per year, which is enough to power 1,500 ordinary EU houses.
How long does a windmill take to pay for itself?
Environmental lifespan assessments of 2-megawatt wind turbines proposed for a big wind farm in the US Pacific Northwest were conducted by US academics. They conclude in the International Journal of Sustainable Manufacturing that a wind turbine with a 20-year working life will provide a net benefit within five to eight months of being put online in terms of cumulative energy payback, or the time it takes to produce the amount of energy required for production and installation.
Is it possible to turn off wind turbines?
To keep the grid balanced when demand for electricity lowers, the National Grid will direct different power plants to reduce the amount of electricity they generate, or possibly turn down generation entirely.
Because turning off wind turbines is far easier and less expensive than turning off a coal-fired power station, wind farm operators are usually the first to be asked to do so when national demand for electricity drops. Even if the wind is still blowing, if a wind farm operator receives a shutdown notice from the National Grid, they will shut down their turbines.
