September 2, 2020 at 9:29 am

Wind energy has been growing rapidly over the past few years

By Sandesh Ilhe

Wind energy has been growing rapidly over the past few years. According to the U.S. Energy Information Administration, it accounted for 7.3 percent of all electricity produced in the United States in 2019—a staggering 300 billion kilowatt-hours (kWh). Most of this wind power is generated by massive commercial wind turbines that sport blades the length of a 747. Occasionally, one does encounter reports of bird fatalities—but wind energy is considered green, nevertheless.

A young company called IceWind has entered the scene from the land of Ice and Fire—Iceland. IceWind has developed a series of innovative micro wind turbines for residents to install in their own homes. The company’s new Freya model utilizes a different approach to capture wind, by incorporating a unique six-bladed design. According to Samuel Gerbus, a mechanical engineer from IceWind, residential wind turbines could help boost U.S. wind energy production to 20 percent by 2030.

“What we have designed over at IceWind is actually a vertical axis wind turbine,” explains Gerbus. “The large difference is those big turbines, when wind comes from different directions, you either need to use a gearbox to change those blades to face that wind direction, or stop them and change it. Vertical axis wind turbines are omnidirectional. We can take wind from any direction.”

Horizontal versus vertical axis wind turbines. (Image courtesy of Power Electronics Handbook, Fourth Edition.)

Horizontal versus vertical axis wind turbines. (Image courtesy of Power Electronics Handbook, Fourth Edition.)

Vertical axis wind turbines (VAWTs) are called such because they use a vertical axis of rotation that stands perpendicular to the ground. VAWTs are considered beneficial in settings with turbulent wind conditions, or in cases where turbines cannot be placed high enough to garner more energy-producing winds.

Horizontal axis wind turbines (HAWTs) are the ones most commonly seen on wind farms. Their axis of rotation is horizontal, or parallel, to the ground. HAWTs typically use a three-bladed rotor that can be positioned either upwind (preferred) or downwind. An aerodynamic lift force is used to generate the driving torque that turns each rotor blade. While HAWTs are able to produce larger amounts of electricity than VAWTs, they generally do not fare well in turbulent winds.

IceWind manufactures robust vertical axis micro wind turbines for on-grid and off-grid use. The Icelandic company was founded in 2012 by CEO and mechanical engineer Saethor Asgeirsson in the shell of a decommissioned coal power plant in Reykjavik. With the adage “extreme energy solutions,” IceWind is committed to designing wind turbines capable of withstanding inclement weather conditions such as hurricanes, blizzards and hail. All of its products are tested in Iceland, an Arctic island known for its harsh weather and severe storms.

“It’s actually quite funny,” says Asgeirsson. “We are the only people in Iceland who get excited when there is crazy wind in the weather forecast. While everyone else is hunkering down at home, we’re huddled around a computer, excitedly watching our data feed.”

IceWind is in the final stages of development after years of testing and fine-tuning its rugged wind turbines. Having successfully launched its products in Iceland, the company crossed the Atlantic last month to bring its VAWTs to the United States.

“We’re excited to begin selling our products internationally,” expresses Asgeirsson. “Our turbines survived Iceland—they will thrive everywhere else.”

What Are Freya’s Features?

The Freya model is a five-foot-tall, six-bladed vertical axis wind turbine from IceWind’s CW100 series.

IceWind’s Freya model. (Image courtesy of IceWind.)

IceWind’s Freya model. (Image courtesy of IceWind.)

The creative design integrates two types of blades that work together to generate power in both mild and extreme wind conditions. The inner blades provide low start-up speeds and a self-regulating braking mechanism in high winds through the implementation of a “Savonieus” drag type design that dates back to the Persian Empire. The outer blades are of a “Darrieus” lift type (i.e., airfoil) design, typically seen on conventional wind turbines and airplanes. These serve to enhance lift properties and get the Freya spinning at higher RPMs, producing more wind energy.

As mentioned earlier, IceWind’s VAWTs provide energy independent of wind direction. The Freya has a cut-in wind speed of 2.5 m/s, or 5.5 mph, which is the velocity at which the turbine will start to generate power. Its rated wind speed is 10 m/s, or 22 mph, at which point it produces the rated power of 160 W. While the Freya is advertised to brake during turbulent conditions in order to avoid potential damage to its system, its cut-off speed has not been provided by IceWind—which asserts that the turbine can continue spinning and generating energy in up to 130 mph wind speeds (Category 4 hurricane conditions).

A rated power of 160 W is not much, so applications for these turbines should be limited to coastal windy regions. The Freya may be able to power your cabin, trailer or barn—but it’s not ready to take your home completely off the grid just yet. This will be illustrated in some calculations later.

The Freya is touted as having an estimated life span of 30 years with negligible maintenance. Gerbus attributes this longevity to excellent material selection and stringent safety procedures. The design incorporates high-grade heat-treated aluminum outer blades and stainless steel inner blades around a carbon fiber axle, enhancing strength and stress resistance. A hydrophobic deicing agent is coated on the turbine to protect against ice, while a proprietary generator seal prevents foreign particles such as dust, ice, water or dirt from entering the generator and interfering with the gearbox.

Assembling a Freya at home. (Image courtesy of IceWind.)

Assembling a Freya at home. (Image courtesy of IceWind.)

The Freya is engineered for simplicity. According to Gerbus, if you can assemble IKEA furniture—and know how to use a torque wrench—you can install a Freya.

According to the journal Biological Conservation, between 140,000 and 328,000 birds are killed annually in the U.S. by wind turbines, with mortality rising with increasing turbine height. Since the Freya is said to be “completely safe” for birds due to its lack of gargantuan whirling propeller-like blades, our aerial friends can now throw caution to the wind.

Gerbus weighs in. “The problem that arises with wind turbines and birds are actually two things: whipper blades and lattice towers. These are the two factors that go into bird safety and are what usually you think of when you hear wind turbines and destroying birds. Whipper blades are like 6+ multiblades—quite sharp—that are available in a lot of commercial horizontal axis wind turbines, and those as well as those lattice structures I just spoke of are most detrimental to birds.”

Additionally, IceWind’s turbines are essentially silent, as all models are known to emit under 30 decibels (dB) of noise.

Speaking of other models, IceWind also has a Njord line of VAWTs for industrial applications.

The RW100 (left) and RW500 (right) are part of IceWind’s Njord series. (Images courtesy of IceWind.)

The RW100 (left) and RW500 (right) are part of IceWind’s Njord series. (Images courtesy of IceWind.)

The RW series are designed to be mounted directly on commercial or military telecommunication towers, communication depots, relay stations and radar outposts in remote locations where conventional energy sources such as diesel generators cannot be implemented. The RW100 has a rated power of 100 W, while the RW500 has a rated power of 500 W.

Do Conventional HAWTs Have Issues with Overspin and Noise, Though?

With all of IceWind’s PR on the company’s noise-free turbulence-resistant wind turbines, one wonders if these factors have really been a problem with conventional wind turbines.

In IceWind’s promotional YouTube video (at 1:35), claims are made of conventional HAWTs catching fire when faced with excessive wind speeds. This is a myth. Further research into wind turbine fires reveals that the primary cause of fires is actually lightning strikes, with other factors including electrical and mechanical malfunctions. Overspin doesn’t even make the list—principally because conventional wind turbines employ their own braking mechanisms and shutdown speeds.

The power curve of a typical HAWT. (Image courtesy of Energy.gov.)

The power curve of a typical HAWT. (Image courtesy of Energy.gov.)

As illustrated in the diagram above, once a conventional wind turbine reaches its rated speed, its power generation remains constant until it reaches its cut-out (or cut-off) speed, after which point the turbine shuts down to prevent rotor strain.

Conventional HAWTs aren’t even noisy for residents living close to wind farms. In fact, GE—a leading manufacturer of wind turbines—took some measurements of their own.

GE’s illustration of noise from wind turbines. (Image courtesy of GE.)

GE’s illustration of noise from wind turbines. (Image courtesy of GE.)

According to the infographic, homes cannot be located any closer than 300 meters from a wind turbine. At this distance, a conventional wind turbine has been found to produce only 43 dB of noise. The noise level decreases to 38 dB at a distance of 500 meters from the wind turbine. Since most background noise is within 40-45 dB levels, all sound from a conventional wind turbine would be completely drowned out.

Is the Freya Cost-Effective for Home Use?

As mentioned previously, a Freya can produce only 160 W of energy in 22 mph winds. Conversely, the average onshore wind turbine has a capacity of 2.5–3 MW and generates more than 6 million kWh in a single year.

How much energy would a Freya generate per year?

(160 W x 24 hrs) x (1 kW/1000 W) x 365 days = 1401.6 kWh per year.

The average European Union (EU) household uses 4000 kWh of electricity every year. That means you would need about three Freyas to power your home fully if you lived off the grid in a European home.

Things get even more dicey if you choose to live in an American home. According to the U.S. Energy Information Administration, the average annual electricity consumption for a U.S. home was 10,972 kWh in 2018. This indicates that you would need eight Freyas to power an off-grid U.S. home.

What if you were using a Freya for supplementary purposes to save on electricity bills?

The average electric rate in the U.S. is $0.13/kWh.

1401.6 kWh x ($0.13/kWh) = $182.2 of savings per year.

Judging from the fact that one Freya costs $3,200, that’s a payback period of 18 years. While IceWind’s turbines are known to be good for 30 years, how many years of warranty does each turbine come with? How much would professional installation cost for connecting the turbine to the grid?

On top of all that, it’s not even realistic to expect a turbine to be operating constantly at its rated power—a best-case scenario based on wind speeds of 22 mph. Most wind speeds are in the 7-11 mph range; a constant wind speed of 22 mph would result in all the trees in your area being permanently bent.

The Freya’s power curve. (Image courtesy of IceWind.)

The Freya’s power curve. (Image courtesy of IceWind.)

Even the windiest city in the U.S.—St. Paul, Alaska—has an average wind speed of just 16.9 mph, or 7.6 m/s. Interpolating from Freya’s power output graph, this would generate only 80 W of power—half of the rated 160 W. So, according to the calculations, a 160-watt Freya would have a payback period of 36 years even in America’s windiest city. That’s worse than the rooftop wind turbines that were analyzed in this article.

As such, while aesthetically fascinating, IceWind’s microturbines cannot replace conventional wind turbines at the present time. They might instead be handy for low-energy outdoor applications that serve to cut down on carbon from generators and diesel engines.

“Let’s not forget all those homes in places like Texas that are continually hit with hurricanes that even the flooding and the weather destroys their diesel generators,” asserts Gerbus. “We’re built to withstand that, certainly.”

IceWind is currently performing testing and viability of further improved designs. There is a plan to release 500-watt and 1,000-watt units, and Gerbus says the company is developing larger-scale models capable of 7-12 times the current power output.

“I think it’s a very dynamic and evolving future,” says Gerbus.

We wait patiently to be blown away.



Sandesh Ilhe

With an Engineers degree in Advanced Database Management and Information Security, Sandesh brings the deep understanding of the digital world to the table. His articles reflect the challenges and the complexities that come along with every disruption in the industry. He carries over six years of experience on working with websites and ensuring that the right article reaches the right reader.

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