If you picture a typical wind turbine, it'll probably look like a giant, triple-bladed fan. Called a horizontal-axis wind turbine, it is by far the most common way to harness energy from the wind, but at its core, this tech is hundreds of years old. Is it really the most efficient way to generate wind energy?
Many people say no. Some of them have decided to design and build their own turbines in the hope of improving an already successful technology. Here, we present nine of those designs. Perhaps one of them will become the new standard turbine some day.
1. Vertical-Axis Wind Turbines
One of the more common turbine variants is the vertical-axis turbine. The particular turbine pictured above generated 4 megawatts of power until it was decommissioned in 1993.
Vertical-axis turbines have many advantages over horizontal ones. Chiefly, the turbine is omnidirectional, which means it doesn't have to rotate to track the wind. This makes vertical-axis turbines simpler and more effective in chaotic wind environments. Other advantages include placing the generator and gearbox at ground level for easier maintenance, and a smaller width allows turbines to be placed closer together.
But it has some disadvantage of its own, specifically that they're not very durable. Vertical-axis turbines experience substantial stress because of the uneven forces exerted on them, and this can cause them to fail sooner than your normal windmill. Still, vertical-axis turbines fill a useful niche, and there are many varying designs still in use.
2. Altaeros Energies' High-Altitude Turbine
The higher up a turbine is placed, the more energy it can generate. High-altitude winds are steady and strong, but the real challenge is placing a turbine thousands of feet above ground. The most common solution involves large inflatable blimps tethered to ground stations, which is what Altaeros Energies decided to do with their Buoyant Airborne Turbine (BAT).
Essentially a small wind turbine sitting inside a large helium-filled body, the whole apparatus floats at approximately 2,000 feet skyward. This high-flying windmill is anchored to a mobile ground station by three load-bearing tethers and one copper cable to transmit electricity. To maximize efficiency, the BAT can move up and down and steer itself into strong wind gusts.
The goal of Altaeros is to build a wind turbine that's cheaper, more efficient, and easier to install than traditional turbines. The BAT's set up takes less than a day, and generates twice as much power as a similarly rated ground turbine. The BAT could be the answer to providing consistent power in remote communities where installing standard turbines is too difficult.
3. Ogin's Shrouded Turbine
Ogin Energy takes regular horizontal-axis wind turbines and gives a 21st-century update. Ogin's turbines are surrounded by a specially designed shroud that funnels incoming wind to increase the turbine's efficiency.
The shroud increases the amount of air passing through the blades, which means Ogin's turbines can operate during lower wind speeds than conventional turbines. The shroud also speeds up the air and reduces drag, which increases the turbine's energy efficiency and allows them to be placed closer together.
Ogin turbines are much smaller than utility-scale turbines, designed for business or residential usage.
4. Kite Power Systems' Offshore Kite Turbine
Credit: Kite Power Solutions Ltd 2015
One company in Scotland is using kites to tap into offshore winds. The company Kite Power Systems is building an installation near Stranraer, Scotland, that will use a pair of kites to generate 2 to 3 megawatts of electricity.
The kites are attached to a long cable, where they float up to a thousand feet above sea level. The kites work in tandem, where one kite rises with the wind and the other falls. The rising kite spins a generator to produce electricity.
One advantage of using kites are that they're simply tethered to a floating barge, which is much easier to install than a rigid offshore platform. Maintenance is easier too, because the generator and most moving parts are at sea level, and installing the kites is cheap enough not to require government subsidies.
However, one big disadvantage is that the kites require constant wind, which isn't the case in many areas. Scotland is an ideal location for this reason, but for widespread adoption the company will have to develop a workaround for when the wind dies down.
5. Tyer Wind's Hummingbird Turbine
One of the more outlandish turbine designs is this one from Tyer Wind. The Tyer turbine takes inspiration from the fast-beating wing movements of hummingbirds. A hummingbird's figure-8 wing movement creates substantial lift and is extremely stable, even during turbulent wind conditions. Tyer is trying to adapt these attributes to wind turbines by using the same movements and wing shape.
The Tyer Wind turbine uses two wing-shaped blades that move in a figure-8 pattern, which generates electricity. The unique turbine design produces a number of advantages, including the ability to operate in higher wind and can be placed closer together.
However, the concept is still untested, and while the wing design works well on hummingbirds, it's not clear if it works as well on a turbine. In tests, it appears to be less efficient than a standard turbine of the same size, and the rapid movement of the blades may lower durability.
6. Challenergy's Typhoon Turbine
Credit: Challenergy/YouTube
Japan's Challenergy has built a turbine capable of harnessing the violent, destructive winds common to the country's frequent hurricanes. Challenergy's turbine uses a radical new design that makes it much more durable so it can withstand those hurricane-force winds. The turbine uses a vertical shaft instead of a horizontal one, and replaces standard blades with vertical columns that utilize the Magnus effect, producing a force when spinning in the wind.
This design allows the turbine's speed to be controlled so that it continues to spin at a steady rate even in high winds instead of locking down like typical turbines. The turbine also fares better in the chaotic, multidirectional winds typical of hurricanes.
Of course, this durability comes at a price. In simulations, Challenergy's turbine was 10 percent less efficient than ordinary wind turbines. Furthermore, the turbine has yet to be tested in an actual hurricane, so it's an open question whether it will actually work the way it's supposed to.
7. SheerWind's Funnel Turbine
While some turbine designs try to lift turbines higher off the ground, Sheerwind's INVELOX turbine takes the opposite approach. Their design places the turbine at the bottom of a specially engineered building that funnels wind down to ground level from a dozens of feet in the air.
Sheerwind's technology uses a large funnel at the top of the building to capture wind and direct it down and through a tunnel. The tunnel narrows at the bottom to increase wind speed, and one or more turbines are placed in this section to generate electricity.
Placing the turbines at ground level makes them easier to install and maintain, while the funnel design lets the turbine take advantage of wind coming from any direction. The design improves efficiency over traditional turbine designs as the company's field tests show an average of three times more energy generated over a similarly sized standard turbine.
8. Windstalk Conceptual Generator
Credit: atelier dna
The Windstalk has been a concept for several years now, and, to be honest, it's unlikely to ever become a real working generator. However, the concept is very interesting, and it's possible it or something similar could be real in the future.
The Windstalk is utterly different from pretty much any other wind generator in the world. The generator is essentially a very tall pole, and works by bending and swaying in the wind. That bending motion generates energy through the property of piezoelectricity. Essentially, the stretching and contracting that happens when the stalk bends creates electrical currents.
The Windstalk has some advantages over traditional turbines, such as fewer moving parts and an ability to be packed in tighter groups. However, no Windstalk has ever been built so it's tough to say whether it's a true viable alternative to conventional wind power. Still, it's a neat idea.
9. Zephyr Energy's Micro Turbine
Credit: Zephyr Energy/Vimeo
Windbeam is a micro-generator able to fit in a backpack that uses light breezes to produce a few milliwatts of power. It's designed to be a small portable charger used in emergency situations or in rural areas without guaranteed access to electricity.
The Windbeam design is simple: a lightweight horizontal beam attached to springs, that can freely move up and down. When exposed to wind, the beam starts rapidly moving up and down. Because of small magnets placed on and below the beam, this rapid movement generates a small amount of electricity.
Windbeam is designed to be simple to build and operate and is made of inexpensive and simple materials. The company envisions a Windbeam in every car's emergency kit. It also has some survival applications since it can also be used to power lights and other small electronic devices in small rural villages and communities without permanent electricity.
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