Wind Turbines For Homes

4 min read

Wind energy is one of the most championed and rooted for sources of renewable energy. It is resourceful, readily available and can work almost anywhere in the world without much tweaking of infrastructure or software. But the issue arises when there is a residential need for wind power with no space to erect a wind farm. This is where the idea of micro wind turbines for homes comes in.

The average electricity production on a micro wind turbine is 400W to 500W, not too far from the average solar panel at 250W to 400W. Micro wind turbines are less complex than normal wind turbines, but still have moving parts. Benefits of these wind turbines include generating your own energy, reducing your carbon footprint, and not being subjected to energy price increases.

Many models of micro wind turbines can produce both direct and alternate current. This means that they do not, unlike solar panels, require an inverter to convert DC into AC, which is required to power your home appliances. Power conversion reduces the efficiency of a system, but not by much. Another benefit is being able to sell excess electricity back to the grid.

However, micro wind turbines do come with drawbacks. For example, they only operate at about 30-40% capacity because wind does not blow all the time. When placed on rooftops, they can vibrate, causing noise and sometimes even structural damage. Furthermore, the average recommended height of a micro wind turbine is 19,8 m, which most roofs do not reach. At this height, there is a very low chance of wind flow interference from buildings, trees and other such structures. Unsmooth wind flow can cause turbulence, stressing the turbines’ components, causing them to miscalculate wind speeds which could result in safety issues. This recommended height would also make turbines unlikely to receive the go ahead from the municipalities of urban areas, making the turbines more suitable for rural areas.

Small wind turbines also cost more than solar PV systems. A 5kW small wind turbine setup in South Africa would cost about R250 000, compared to about R110 000 for solar. Modern wind turbines have an average annual maintenance cost of 1,5-2% of the original cost. Solar essentially has no maintenance costs since it does not have moving parts, unlike wind turbines.

Vertical-axis turbines

Vertical-axis turbines are turbines with blades perpendicular to the ground and can be powered by wind coming from any direction. There are many companies around the world working on developing vertical-axis wind turbines. One such company is Icewind. They offer two wind turbines; one for residential and one for industrial use. The residential use turbine, called the CW100, comes in the following variants:

• $3 200 (R56 320,35) for the turbine alone,
• $4 150 (R73 040,46) for the turbine with an on-grid system,
• $4 800 (R84 480,53) for the turbine with an off-grid system (excluding batteries).

The CW100 has a rated power of 160W, a max power output of 600W, starts generating electricity at a wind speed of 7,2 km/h, can function with wind speeds of up to 209,2 km/h, has a noise level of less than 30 dB (as soft as a whisper), is 1,5 m high and weighs 65 kg. 

Dutch company KETECH also has their own vertical-axis wind turbines called the Archimedes Windmill. The two models that can generate between 125W and 1 000W, start generating electricity at a wind speed of 3,2 km/h, can function with wind speeds of up to 180 km/h, have a noise level of less than 45 dB (quieter than a fridge), and weigh 32 kg and 120 kg. 

None of these are for sale yet, only available for pre-order.

The RidgeBlade® is a wind turbine that uses the existing slope of a roof to harness wind by capitilising on the Aeolian wind focus effect (wind travels over a roof’s sloped surface and creates a pinch point at the roof peak, or ridge, accelerating airflow through the turbine). It is claimed that the RidgeBlade generates 9 times more electricity than a traditional horizontal-axis turbine when in airflow places, and generates electricity at full capacity with wind speeds of 39,6 km/h. It can endure turbulent winds, is quiet and vibration-free. Their RB1 Residential turbine can produce 2kW of power. This turbine is currently available for sale.

In a really outlandish innovation, designer Joe Doucet produced a wind turbine wall consisting of 25 wind turbine generators with blades spinning in the middle. The wall is 2,4 m high and 7,6 m wide and can produce up to 10kW. At 35% capacity, it will provide about 84kWh a day, which is really good considering the average home in South Africa consumes 30kWh a day. This is, however, only a prototype meaning that the real numbers could be much lower. 

Although all of these wind turbine systems for homes look and sound promising, it is important to remember that they are not readily available on the market and are still in the works before they can be fully released to the public. We also have to be weary of the fact that performance figures reached in testing are often much higher than those realised for mass produced products. Although we may remain optimistic for the future, these innovations are likely still years away from fully materialising.

Summary

• Traditional wind turbines have many moving parts which make them too complex for residential use.
• Micro wind turbines are too expensive, too complex and too unpractical for residential use when compared to solar.
• Many companies have developed residential-friendly micro wind turbines.
• These micro wind turbines are still in the developmental stages and not widely available to the public.

What are your thoughts on wind turbines for homes? Would you get one over solar panels and other renewable energy alternatives? Share your thoughts by replying to this email!

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