Small Wind: Buyer Beware!

Small wind solutions are increasingly becoming financially viable thanks to local and federal incentives, and from a technical perspective the quality factor is improving. The historically negative aspect about installing a small wind solution was that it would take an extraordinarily long period of time to pay back associative costs; if ever during the expected life span of the wind turbine generator.

From my vantage point ‘quality’ and ‘pricing’ in small wind are among the largest concerns. However, of greater concern is that there seems to be a growing abundance of misleading, if not deceptive advertising and false or unrealistic claims by many manufacturers. These take the form of claiming higher energy output, faster payback periods (using higher than what can normally be expected wind speeds in their energy calculations), and other types of unethical claims and behaviors.

But help is on the way, manufacturers of small wind turbines that form the legitimate face of the small wind industry are in the process of creating accountability within their segment of the industry. In addition to industry events, we are seeing the advent of the Small Wind Certification Council. We may soon see a certification process that will eliminate the industry’s seedier side. New small wind turbine generators are rapidly emerging from individual’s garages to manufacturers in both newer vertical and the more traditional horizontal models.

Vertical wind technology remains in its infancy and energy power output claims by manufacturers are almost always overstated…sometimes grossly overstated (the same applies for many horizontal wind turbine generators on the market). In my view, only one vertical wind turbine generator (VWTG) manufacturer is really trying to get it right (I applaud Mariah Power) by subjecting its product to the testing rigors of the National Renewable Energy Laboratory (NREL). After NREL suspended testing for mechanical failure, Mariah Power continues to try and ‘get it right’ through modifications and through an independent testing regime. As of today WECC does not recommend any vertical wind turbine generator to our clients.

Note: Relative to the topic of VWTGs, Mick Sagrillo offers a strongly worded and germane Open Letter to Vertical Wind Access Turbine Manufacturers – worth the read!

We must recognize that in the current environment in most cases the manufacturer claims of power production, payback, power curve, size of generator vs. actual power output, and conditions of internal testing are solely the manufacturer’s, and the consumer must be able to trust that information that is presented to them is indeed reliable. In my view, to determine legitimacy any small turbine as a viable small wind solution, the manufacturer must subject their machine to the rigors of independent testing until such time that the Small Wind Certification Council has codified its processes and independent testing/reporting becomes an industry standard. Using the power curve and energy output data from an entity with no connection to the manufacturer adds strength and proves the manufacturer’s assertions. Up until now in most cases, we only have the manufacturer’s data in order to complete a cost/benefit analysis before purchasing a small wind turbine generator.

A sad fact is that in the past year many, many inventors and manufacturers are emerging in the ‘small wind’ space and the ‘checks and balances’ are not yet in place to protect the burgeoning small wind industry from itself. Until the Small Wind Certification Council gains some ‘legs and teeth’ and the legitimate small wind manufacturers gain momentum in policing the industry, we can expect continued consumer confusion and in some cases, unchecked deceptive practices. The long and short of this is Small Wind: Buyer Beware!

Article written by Wayne Hildreth
Email Wayne at hildreth@frombeginningtowind.com
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Small wind - Is it right for you?

The search for affordable and sustainable energy sources in today’s struggling economy may have you looking toward the small wind market. Small wind projects –those 100kW and below - can prove beneficial for small businesses, homes, manufacturing plants, schools and municipalities given the right conditions. However, small wind is not feasible for every situation. Before thinking any further about a small wind project, consider the following.

Small wind is a practical solution for you if:

You have sufficient wind

No wind, no go. A wind speed of at least 6 m/s, or 12mph, is the current standard for feasible and economically viable wind projects of this size.

You have enough space to support the project

A general recommendation is at least one acre of space in a rural setting. It may work in urban settings however, if there is an unobstructed wind flow. Wind turbines work most efficiently when the wind flow is streamlined.

Tall structures are allowed in your area

If there are strict zoning ordinances in your area that would prevent a feasible turbine tower height, small wind may not be right for you. We recommend a fall zone of at least one and one-half the length of the turbine.

You have a realistic picture of your energy demand

Small wind projects can reduce your electricity bill by 50-90%, given an adequate wind resource and hub height. The key is matching your energy demand to turbine power output.

You are comfortable with a long-term investment

Although incentives and grants make wind energy projects more competitive and economically feasible, small wind projects will generally have a longer payback period compared with other investments. If you are looking for a quick return on investment, small wind probably isn’t for you.

Article written by Sarah Smith

Email Sarah at smith@frombeginningtowind.com

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Common mistakes to avoid in your small wind project

A large fraction of small wind projects turn out to be subpar financial investments because of simple mistakes made in the initial phases of project development. This entry focuses on those common mistakes and provides simple steps that can be taken to ensure a more viable project from the performance and financial perspectives. For more details see the associated whitepaper.

Small turbines, with power ratings of less than 100KW, are being installed at a rapid pace. These wind projects are being used to power small businesses, buildings, malls, houses and a variety of other applications. Unlike the multi-million dollar large scale projects that undergo rigorous wind resource, siting, and financial assessments, small wind projects undergo significantly less analysis and preparation. The end result generally reflects the lack of preparation, as turbines produce less energy than advertised.

In order to attain on par financial performance of small wind projects the following due diligence must be performed:

• Ensure that the energy production used in the calculation is based on your local wind conditions and based on independently tested or certified power curve.
  
• Ensure that the wind speeds used in the calculations have been verified through onsite measurement or some other means.
  
• A location has been chosen that will receive unobstructed wind and minimum turbulence from obstacles and local vegetation.
  
• Ensure that the turbine is well built and is suitable for your environment and,
  
• Check if the turbine is certified; if it is not, obtain test results
  

If the proper due diligence is not performed you are likely to be negatively surprised by the results.

Article written by Dr. Pramod Jain

Email Pramod at pramod@frombeginningtowind.com

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Wind Energy from Rooftop Turbines—Does it make sense?

There is immense interest in capturing wind energy with turbines installed on rooftops. This blog entry and the associated whitepaper will answer the questions: Does it make sense to place a wind turbine generator on a roof?

Examples of prominent rooftop installs include: Twenty 1KW Aerovironment turbines at Boston's Logan Airport, the Brooklyn Naval Shipyard, and on top of comedian Jay Leno's garage.

The results of rooftop installs are not encouraging. The Massachusetts Technology Collaborative (MTC) sampled 19 small wind turbines installed using MTC grants. The data revealed that the actual average power output is only 27 percent of that estimated, with the high being 59 percent and the low an abysmal 2 percent. As a result of poor performance, in the fall of 2008 MTC cancelled the small wind initiative.

What is not to like about rooftop turbines? These are some of the positive considerations: Wind speeds increase with height; the wind tends to accelerate as it rises over the eaves of the building; there is nothing on the roof anyway; and, energy is produced very close to where it will be used.

Some of the negatives are: Due to the eaves and building contour, there tends to be a sharp increase in turbulence that causes excessive and unbalanced loads on the turbine that lead to premature component failure; residential and most commercial roofs are not suitable as they were not designed to carry the additional weight, dynamic load and vibration of the wind turbine generator; commercial metal roofs are not suitable because of vibration induced noise; turbulence causes energy output to reduce significantly; turbulence causes the life of turbine to be significantly shorter; the orientation of the building significantly impacts the airflow; rooftops produce the rated amount of energy only when the wind direction is in a small 30 degree sector, and in all other wind directions there is a sharp drop in energy production.

At the recent 2009 American Wind Energy Association annual convention, Brad Cochran of CPP presented a paper on "Optimizing the Placement of Building Integrated Wind Turbines." The authors contend that:

• Proper placement of turbines on the roof is essential. The wind speeds can range from 0.1 to 1.5 times that wind speed at eave height. A location closest to the eave that is perpendicular to the predominant direction of wind is the best.
  
• Building orientation with respect to predominant direction of wind is important. The widest part of the building should be perpendicular to the predominant direction of wind. Rooftop installs makes sense only in situations where the most favorable wind conditions are in a 30 degree sector.
  
• Height of building and height of turbine above roof are important. A 400 ft building will experience significantly higher wind speeds at roof level compared to a 40 ft building. 30 to 50 feet above the rooftop will experience normal turbulence levels; any turbines below this height will encounter high turbulence intensities.
  

In conclusion, a rooftop turbine install makes sense in the following situations:

• Building is in a high wind area and the building is tall. The average wind speed at hub height should be at least 6 m/s, preferably higher.
  
• The predominant energy from wind is in a 30 degree sector. The orientation of the building must be such that the broad side of the building is perpendicular to the predominant wind direction.
  
• Turbine should be at least 30 ft (preferably 40 to 50 ft) above the rooftop and any other taller structure in the vicinity. For shorter buildings (20 ft or lower), consider other alternatives like installing turbine on a 70 to 100 ft pole. Any hub height less than this will not see sufficient wind resource.
  
• Rooftop must be able to withstand the moments due to forces on a 30 ft cantilever. Roof must also be able to withstand the weight of the turbine. Roof must be of thick concrete so it does not vibrate.
  
• The turbine should be located as close to the eave as possible.
  
• The selected turbine must be tested in high shear and high turbulence environment because a roof will experience such conditions.
  

Failure to follow these guidelines will lead to significant reduction in wind turbine output.

Article written by Dr. Pramod Jain

Email Pramod at pramod@frombeginningtowind.com

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