Although it is popular, wind energy has some critics who often raise several issues. Some of the main disadvantages of wind energy include the following:
1. Noise pollution
There are two potential sources of noise from a wind turbine: mechanical noise from the gearbox and generator, and aerodynamic noise from the rotor blades. Aerodynamic noise is the main component of the total noise, which is similar to the swish sound produced by a helicopter. At 400 m downwind, the turbine noise can be as high as 60 dB, which is equivalent to the noise level from a dishwasher or air conditioner. Although the noise from wind farms is far below the threshold of pain, which is 140. dB, it is a major annoyance to some people.
Noise used to be a very serious problem for the wind energy industry. Some early, primitive types of turbines built in the early 1980s were extremely noisy, to the point that it was annoying to hear them from as much as a mile away. The industry quickly realized that this problem needed to be dealt with, however (particularly in Europe, where turbines are often located in or near residential areas), and manufacturers went to work on making their machines quieter. Fortunately, newer low-speed and better designs of rotor blades have reduced the aerodynamic noise dramatically.
Designers of wind turbines believe their creations look pretty, but, unfortunately, not everyone agrees. Critics see wind farms as a defacement of the landscape, forcing developers to install them in remote areas, including offshore. Besides, when the blades of a turbine pass in front of the sun, it can create a recurring shadow, often referred to as shadow flicker. Simple siting measures, such as adequate setbacks and vegetative buffers, can be used to moderate this effect. Using computer models, developers can determine the days and times during the year that specific buildings in close proximity to turbines may experience shadow flicker.
3. Bird collisions
Instances of birds being hit by the moving blades have been reported. However, newer turbines are designed for low blade speeds, which reduce the severity of the problem. Offshore turbines create reefs in their base, which is good. The reef attracts fish, which is also good. The fish attract birds to feed on them, which is good as well. But, the increased number of birds may cause more bird collisions. Some see this as an acceptable outcome as the dead birds become food for the fish!
Offshore wind systems are not placed in the shipping lanes, so obstruction to large ships is unlikely especially when the blades reflect radar signals and can be easily detected. Most offshore wind turbines are equipped with warning devices to alert ships in foul weather. However, recreational boating and small fishing vessels may stray in the area.
5. Ice accumulation
In areas with cold weather, ice can accumulate on the blades. When the turbine rotates, the ice can be dislodged and turned into projectiles endangering people and structures in the area. In some wind turbine models, the blades are heated to prevent the ice from accumulating on the blades.
6. Sunlight flicker
Some blades reflect sunlight. When these blades rotate, the reflections of the sunlight on these blades create light flickers. This is an annoyance to some people.
7. Voltage fluctuations
A large number of wind turbines use induction machines as generators. These machines are very rugged and require little maintenance and control. They are also self-synchronized with the power grid without the need for additional synchronization equipment.
However, because the induction machine has no field circuit, it demands a significant amount of reactive power from the utility system. When used in the generating mode, the induction machine consumes reactive power from the utility while delivering real power. In some cases, the magnitude of the reactive power imported from the utility exceeds the magnitude of the real power generated. Further, the reactive power consumed by the generator is not constant but is dependent on the speed of its shaft. The voltage at the wind farm is dependent on the reactive power consumed by all wind turbines in the farm; the higher the reactive power, the lower the voltage.
8. Wind production misalignment with demands
Most of the electrical loads peak in the morning and early evening. During these times, utilities often fire their fossil fuel power plants to compensate for the extra demands. Renewable energy can play a great role during these periods by supplying extra energy. However, because the wind is not reliable, energy from wind farms is not always synchronized with the increase in demand.
9. Variability of wind
The wind is continuously varying and somewhat unpredictable. It can be challenging to predict exactly how much electricity a wind turbine will generate over time. If wind speeds are too low on any given day, the turbine’s rotor won’t spin. This makes the power production from wind farms less reliable than conventional power plants.
10. Location limitations
In order for wind turbines to be economically viable, they need to be installed in a place where they will produce enough electricity. Wind farms are best suited for coastal areas, the tops of hills, and open planes – essentially anywhere with strong, reliable wind.
Most of these suitable places tend to be in remote areas far outside of cities and towns, in more rural areas, or offshore. Because of this distance, new infrastructure, such as power lines, have to be built in order to connect a wind farm to the power grid.
11. Expensive to set up
Generally, wind power is on the high end of cost, with coal and nuclear being on the low end. The manufacturing and installation of wind turbines require heavy upfront investments. A modern wind turbine generating 2 megawatts of electricity costs 3.5 million USD just to be installed, let alone additional costs such as operational and maintenance costs. Factors such as the spatial distribution, intermittency of wind resources, and long-distance electricity transmission add extra cost for the wind power to be delivered to the consumers which influence the economic growth in this sector.
Wind energy systems can involve the transportation of large and heavy equipment, causing a large temporarily disturbed area near the turbines. Erosion is another potential environmental problem that can stem from construction projects.
The cost will obviously vary depending on the size and type of your chosen wind turbine. You can buy small turbines but these will produce very little output.
12. The need for maintenance
The technical availability of wind turbines is high, this has mainly to do with fast and frequent service and not with good reliability or maintenance management. From time to time you’ll have to replace worn parts and although most modern wind turbines should last around 20 – 25 years you will likely have to replace the inverter after 8-10 years depending on the size and type of turbine you have.