Walking the floor of WINDPOWER 2008, the annual conference and trade show for the wind energy industry, one couldn’t help but be transfixed by all of the different types of turbines - at least I couldn’t. The wind turbine has become the iconic symbol of clean, renewable energy. But the classic three-bladed horizontal axis wind turbine, with its gracefully swooping blades, has become the symbol of not only renewable energy, but also of environmental consciousness and ecological possibility.

Despite the ubiquity of the three-bladed turbine, the oft-overlooked vertical-axes turbines are making quite a splash in the world of wind energy, especially in small and micro-applications. So what’s all the fuss about? Vertical-axis turbines apparently do not suffer from some of the same problems that plague small wind applications in urban settings including, aesthetic concerns, space requirements and sound levels.

Other advantages of vertical-axis turbines:

• Can produce up to 50% more electricity per year than conventional turbines with the same swept area
• Generate electricity at much lower wind speeds, as low as 4 mph (1.5 m/s)
• Will continue to generate power in high wind speeds, up to 130 mph (60m/s) depending on the mode
• Direct-drive units have no gearbox. No gearbox means a more efficient transfer of energy and no leaking oil
• Will not harm wildlife, in terms of bird and bat strikes

Below, I’ll cover some more basic differences and show you a few photos and short videos of some of these turbines I saw down in Houston at WINDPOWER 2008.

The designers from Taiwanese start-up A.N.I.T.A. Energy (pictured above) showed me why their models have a low start-up wind speed, and that is because of the light metal bands you can see surrounding the turbine itself. Apparently this design allows users with a less substantial wind resource (particularly those in urban applications), squeeze some electricity from the local winds. The larger model pictured above (and in the second video below) is scalable and can be stacked as many as three-high and integrated with the rooftops of large buildings.

Unlike three-bladed designs, vertical-axis turbines do not need to “right themselves” into the wind, they are always in a fixed position in terms of their orientation. A few of the models I saw, most notably the designs from the Korea-based KR Windpower, (video above) had a manifold-type device that would swing around and funnel more wind into the turbine from the direction the wind was strongest.

Another design I saw scattered throughout the show floor were those that integrated small solar and wind together on the same unit (top photo and photo below). The unit below integrates both solar and wind onto a single 400W streetlight platform.

The turbine itself is a “GUS” from a company called Tangarie which features a reflective coating that reduces glare and can even be slathered with an advertisement or a state flag of Texas, as is the one below. The complete solar/wind/streetlight/pole package (made by another company altogether) costs about $7,000, not including installation.

There will undoubtedly be substantial growth in the vertical-axis turbines, especially in urban settings. Personally, I think this technology could best be applied in poorer countries to help address the most basic of energy needs, like lighting and light-duty water pumping.

Other Posts on Small and Micro Wind Energy:

“Top Five Micro Wind Turbines”

“Liveblogging from WINDPOWER 2008: Photos of Small Wind Turbines”

“Small Wind Remains in Farm Bill”

All Photos © Timothy B. Hurst

*Thanks again to the American Wind Energy Association for providing travel and conference support to WINDPOWER 2008.

According to Ryan Grimm at Politico.com, when asked what the President would do if the current iteration of the farm bill made its way to the President’s desk White House spokesman Scott Stanzel replied, “as it stands now, it is not something the president would support.” Stanzel wrote in an email:

“The proposal before Congress would dramatically increase spending, in part by masking additional spending in budgetary gimmicks and accounting tricks.”

Farm bills pass - that’s what they do

Despite the threat, there may be enough Congressional support to override the veto. According to House Agriculture Committee Chairman Collin Peterson (D-MN), “If the White House is stupid enough to veto this, they’re going to get overridden.”

The farm bill is a very popular funding mechanism for Congressional spending. Every state’s congressional delegation works extremely hard to get their slice of the agricultural pie - not doing so does not bode well in the eyes of powerful ag interests and the voters of agricultural states. In short, farm bills do not get vetoed. At least very rarely do they get vetoed - there are a few exceptions.

One exception to the rule is when a second term president uses a veto (or threatens to veto) an appropriations bill, such as a farm bill - and criticize Congress for loading it with pork and earmarks - without any serious political repercussions. Interestingly enough, the last time a farm bill was vetoed was nearly 10 years ago, when another late second-term president successfully vetoed a farm bill - a veto which Congress made no attempt to override. But the political climate is quite different from that of ten years ago, and I would suspect that this President does not have the political capital to successfully veto the farm bill.
See also: “Small Wind Remains in Farm Bill” :: Green Options (12/2007)

Photo: mike138

See also: Top 5 Micro Wind Turbines

The economics will be different for everyone, so I am not necessarily encouraging you all to run out and buy a micro wind turbine. I will also warn you that interconnection laws vary by country, state, province, municipality, etc. So, before spending ANY money on one of these gizmos, be certain that you have an adequate wind resource, and if you are planning on connecting to the grid, that you understand the interconnection standards that apply. Please use this information with caution: you must not cloud your judgment with mental images of backward-spinning electric meters and negative utility bills. While this is possible, you don’t want to spend all of your hard-earned money on a micro turbine that your local HOA, planning board, or zoning commission never lets you put up.

I should also note that while vertical axis wind-turbines may be the wave of the future for small-wind (especially in urban settings), there are lots of companies making big claims about their products right now, and I am not comfortable with my own knowledge of the products to include them in this listing.

Note: prices listed are the manufacturer’s suggested retail price, it is quite possible to find them for less (nobody pays ‘retail’ anymore, right?)
1. Southwest Windpower Skystream 3.7
The Skystream 3.7 is the first fully-integrated, grid-tied wind energy system designed for residential use. The product is an all-inclusive wind generator (with controls and inverter built in) designed to provide quiet, clean electricity in very low winds. Unlike many other turbines, the Skystream 3.7 will turn downwind because it has no tail rudder to keep it facing into the wind.

Cost: $5399 (not including tower and installation materials)
Rated Capacity: 1.9 kW continuous output, 2.6 kW peak
Startup Windspeed:8mph
Rotor: 12 feet (3.72 m); 50-325 RPM
Interconnection: Utility connected or battery charging
Alternator: Gearless, permanent magnet brushless
Voltage Output: 240 VAC (Optional 208 VAC)
Estimated Energy Production: 400 kw per month @ 12 MPH (5.4 m/s)

2. Southwest Windpower Air X
The AIR is the world’s number one selling small wind turbine. The redesigned Air X incorporates a new microprocessor-based technology that results in increased performance, improved battery charging capability, greater reliability and the reduction of “flutter” noise from the machine. The Air X is ideally designed for powering small appliances in off-grid installations, remote communications facilities, marine applications, and communities in the developing world.

Cost: $600
Rated Capacity:400 watts
Startup Windspeed:8mph
Rotor: 46 inches (1.14 m)
Interconnection: Battery charging
Voltage Output: 12, 24, 48 VDC
Estimated Energy Production: 38 kw per month @ 12 MPH (5.4 m/s)

3. AeroVironment Architectural Wind
Architectural Wind is a small, modular wind turbine system designed for installation on buildings in urban and suburban areas. This is done by eliminating the support tower, reducing noise and vibration, and creating a modular housing that installs quickly and easily onto buildings, without penetrating the roof.

The turbine design has received critical praise for a while now, receiving the Red Dot International Design award and a 2007 Annual Design Review award. With a sleek, color-matched series of specially designed, highly efficient and low profile wind turbines, property owners can integrate Architectural Wind systems easily into new and existing buildings. As Preston at Jetson Green pointed out, the AeroVironment turbines have been installed at the new Kettle Chip facility in Beloit, WI that can produce roughly 28,000 kilowatt hours of power per year under normal wind conditions.

Architectural Wind is scalable and works very well in urban environments. The price and output of the machines will vary because of the drastically different requirements of individual installations. If you need more information on cost and specs, you can contact AeroVironment through their website.

4. Southwest Windpower Whisper 500
The Whisper 500 can produce enough energy to power a small to moderately sized home. Formerly the Whisper 175, the Whisper 500 was completely redesigned in 2004 to work in harsh, high wind environments. The Whisper 500 is a two bladed fiberglass reinforced blade and incorporates a patented “angle governor,” designed for quiet operations in high winds.

Cost: $7,095
Rated Capacity: 3kw
Startup Windpeed: 7.5mph
Rotor: 15 feet (4.6 m)
Interconnection: Utility connected or battery charging
Voltage Output: 24, 32, 48 VDC or 240 VAC
Estimated Energy Production: 1500 KWh/month @12.5mph

5. Bergey Excel
The Bergey Excel is designed for high reliability, low maintenance, and automatic operation in adverse weather conditions. It is available in two configurations: battery charging and grid-tied. The Excel is a ruggedly built turbine that comes with a 5 year warranty. In a moderate location, the Excel 10kw can provide enough electricity for the average home.

Cost: $21,900-$27,900
Rated Capacity: 10kw
Startup Windspeed:7.5 mph
Rotor: 22 feet (6.7 m)
Interconnection: Utility connected or battery charging
Voltage Output: 48 VDC or 120, 240 VAC
Estimated Energy Production: 1500 KWh/month @12.5mph

Additional Resources:

American Wind Energy Association - Small Wind

Wind-Works

OTHERPOWER.COM

The Alternative Energy Store

All pictures are courtesy of the manufacturers.