When I drove past a field of wind turbines recently, I wondered how much space is required between each machine in order for them to work properly. So, I did some research to find out how far apart wind turbines have to be.
How far apart to wind turbines have to be? Wind turbines require approximately 7 rotor diameters of distance between each other in order to achieve maximum efficiency. The exact measurement of the required minimum space will depend on the size of each individual turbine and length of its blades.
Since wind turbines are tall structures that stand upright and do not have a lot of width, they do not require a lot of land to hold an entire group of them or create a wind farm. However, there are certain minimum requirements that must be followed for best results and maximum wind energy output.
Related: Where Can A Wind Turbine Be Built?
The Space Between Wind Turbines
The wind energy industry has been growing rapidly in the past several years, with a steady growth rate that is increasing more with each day that goes on. In fact, wind energy has a growth rate of approximately 30 percent each year that is moving steadily uphill. There are close to millions of wind turbines all across the globe, and it seems like more of them are popping up in every direction almost every other minute.
Although there are so many wind turbines all over the world, there are regulations in regards to how far apart they should be spaced. These limitations are in place in order to maximize the efficiency of the machines and prevent damage to the hardware and parts of the outside of the turbine.
Larger turbines that are on a utility-scale will require much more room in between them than a smaller residential turbine that might reside in the backyard of a farmhouse. Some turbines have the energy capacity to create several megawatts of energy, which translate to one million watts each.
As an example, take into consideration a large industrial turbine with an energy capacity of 2 megawatts. This particular machine would require approximately one and a half acres of land in between itself and another turbine or itself and any obstructing objects including buildings or fences in the area.
For smaller wind turbines, there will be less space required and multiple of these machines will be able to be placed on a less spacious amount of land and still be able to function properly.
The general rule of thumb for calculating the minimum distance that should be placed in between each wind turbine is the approximate measurement of 7 rotor diameters of the specific blades of that turbine. The diameter can be calculated by measuring the length of one of the rotor blades extending outward from the center of the rotor hub.
This calculation of the rotor blade’s diameter will then be multiplied by the number 7 to determine how much of a distance should be established between each turbine.
What Can Happen if the Turbines are too Close Together
There are certain logical reasons that motivate the space limitations that should be placed between each functioning wind turbine. The first and most obvious reason for these general rules is so the turbines do not run into each other while they are spinning with the wind.
Wind turbines possess very long rotor blades that spin with the wind and work to harness its kinetic energy in order to take it in and convert it to usable electricity using a variety of components within itself.
These blades must be long in order to effectively generate power from the wind and essentially scoop the air into its center almost like they are the machine’s arms. Therefore, if two different wind turbines were placed directly next to each other with little to no space in between them, the blades would likely crash into each other when any kind of wind speed is present. Wind turbines move according to the speed of the wind, so faster wind speeds translate to faster rotation speeds.
In the event of a severe storm or extremely high wind speeds, if one of these turbines was to suffer any damage to the hardware, it could transfer over to the next turbine. For example, if the first machine’s braking mechanisms were not working properly during a harsh wind storm and an outer component like one of the blades flew off of the machine, it would immediately interfere with the other turbine, most likely causing severe damage to it as well.
Aside from the most obvious physical reasons, there is an additional theory that supports the reasoning for spacing out wind turbines according to regulations. This theory is known as the “wake effect”. It concludes that some wind turbines are able to take more energy than others if they are in certain locations. More specifically, the wind’s kinetic energy can be slowed down or completely taken away by a wind turbine that is too close to the same area as another group of turbines.
Take a small wind farm as an example, with several wind turbines within a small space without too much room in between them. If the wind began to blow in the direction of 2 of the turbines that were located in front of the others, those turbines will begin to sense the wind speeds and turn their blades to collect the kinetic energy.
These 2 turbines would be able to gain from the full amount of kinetic energy supplied by the wind, as they would be the first turbines to have access to it.
The other turbines directly behind them, however, will not be able to gain the full amount of kinetic energy from the same gusts of wind, because the turbines in front of them slowed down the momentum, so they might only get a small percentage of energy. This happens due to the fact that kinetic energy in any form is created by a consistent movement.
Therefore, when the wind freshly grazes the blades of a turbine without any interference before it, that turbine will gain all of the possible energy the wind turbine has to give, or at least as much energy as they are able to take from it at any given time.
When something obstructs the wind’s path to the next object that is behind it depending on the given direction of the breeze, the obstructing item will take the majority of that kinetic energy that is promoting movement of the wind, and the speeds will be automatically slower when they pass the first machine. s
Do wind turbines need even more distance between them?
On average, it has been reported that each wind turbine currently requires a distance of approximately 300 feet between them. This is equal to an estimated total of 7 complete rotor diameters for the averagely sized wind turbine.
In recent research, it has been hypothesized that wind turbines might even need a little bit more space between them, exceeding previous limits for minimum spacing requirements. A study that was conducted at Johns Hopkins University proposed that for maximum efficiency, each wind turbine will require much more space to collect and convert energy as freely as possible.
The total space required will include a variety of factors, including efficient space for the concrete foundation underneath the towers that work to keep them standing upright into the wind. This should be a stage in the initial planning of the wind project, and the foundations of each turbine should not interfere with any others to create adequate space.
The distance between the field of wind turbines and nearby power substations should be properly measured and planned out as well. The results of the research confirmed that there should be an average for 4 megawatts per square kilometer accounted for when planning a wind farm project.
How Space Between Turbines Affects their Efficiency
The minimum space requirements for large quantities of wind turbines are necessary to follow for the best results and highest profit margins for the owners of the machines. The wake effect is a vital concept to understand because insufficient space between each machine can greatly affect the functionality and profitability of a wind turbine.
If there are too many of them grouped into one location, they can possibly steal the wind from each other, causing lower percentages of productivity throughout the entire farm.
To be clear, it is impossible for the wind to ever run out or be taken away completely. Since the wind is a natural resource that is infinite and renewable, there will never be a shortage of wind supply on the earth at any time. However, as mentioned before, it is possible to interfere with the speeds that the wind will be able to provide as it moves along a certain path when its energy is slowly being taken from it by different machines.
If the machines were to be placed without enough space in between them, causing the wind efficiency percentage to be significantly lowered, the owner’s investment in the turbine would essentially be a waste.
Considering the large amount of capital that is required upfront to purchase and install each wind turbine, the investor would not receive the expected return on their monetary investment if the turbine was not even producing an energy return.
The Space around Wind Turbines that are built on Existing Farms
It is common for wind turbine owners to seek out land that can be rented out for the construction of their machines, in order to avoid the cost and commitment of purchasing their own land for their new wind farm. The farmer and the turbine owner will come up with a lease agreement with terms that they can both agree on, that will include a set amount of payments for the duration of the renting period.
An average payment amount that a farmer would typically receive from someone who is using their land to build and use wind turbines is approximately eight thousand dollars. Additionally, these agreements will usually last for multiple years at once, with an average of about 5 years per lease term.
Within the several years that are rented out by the turbine owner, they will commonly be granted a period of a few years that are specifically dedicated to building the initial turbines as well as adding more.
For example, a turbine owner who has signed a 5-year lease agreement might be able to build as many turbines as they would like on the land for the first 2 years of the time they have with the land. The rest of the duration of the lease would be dedicated to generating electricity only.
Most of the landowners who offer leased space to investors in the wind turbine industry will already have existing farms, most likely with cattle and livestock. So, how would the space around the wind turbines be affected in this situation?
Well, the same regulations for the minimum distance between the turbines and any obstructive object like a house, shed, or barn would still stay the same.
Each machine would have to be at least 300 feet away from anything that it could possibly cause damage to or that could interfere with its collection of wind energy. As far as the cattle and livestock that inhabit the same area as the wind turbines, there is no direct harm that will be inflicted onto the animals from just being close to the machines.
In fact, many cows and horses actually roam around the grass near the bases of the turbines and eat the grass in the area as well. The actual machine will not cause any physical damage to the animals, because the rotor blades are held at such a high distance in the sky, and it is not required for them to be distanced from the turbines.
However, the other adverse effects that wind turbines can have on farm animals and wildlife is an entirely different question.
In conclusion, there are certain minimum space requirements between all wind turbines that should be considered and closely abided by.
Although there have been disputes about how much distance is really required between each machine to help them become as efficient as possible, it can be agreed upon that there must be a sufficient amount of distance throughout a wind farm, regardless of what the exact measurements may be.
What is the efficiency of the average wind turbine?
The energy efficiency of the average wind turbine is approximately 85 percent. In other words, each wind turbine will be working to produce electricity from the wind for about 85 percent of its lifetime or less. This percentage can be as low as 70 percent in some cases, depending on the size of the turbine and the climate in the location where it is located.
In general, offshore turbines that are located in the middle of the ocean experience more consistent wind and turbulence throughout their lifetimes, and will, therefore, be more efficient than onshore turbines that are located in fields on land.
How does a wind turbine spin its blades?
A wind turbine goes through a variety of separate processes in order to effectively spin its blades and collect energy to be converted into electricity. The entire process begins when the turbine picks up on the speeds of the wind and sends a message through to one of the largest components of the machine. This component, called the nacelle, is home to multiple different individual parts that all work together toward the same goal.
Throughout these processes, a piece called the controller will send a message forward toward the blades, letting them know at what speed they should begin to spin. After this process has been initiated, the blades will gain lift from the speed and pressure of the wind and proceed with collecting energy from it to generate electricity.
How much land is required to build a wind farm?
Although each wind turbine must have a certain amount of field space in between them before they can come in contact with other machines or obstructive objects, there is only a relatively small amount of land that is required to build an entire wind farm. Since the wind turbines are longer lengthwise than their widths, the measurements between each machine are not as much as it would be if the turbines took up more space themselves.
There are also ways to avoid purchasing land for the sole purpose of building wind turbines on it. Many people with existing land or farms will offer leases to wind turbine owners that will allow them to build their machines and generate energy on their property for a set monthly fee.
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.