About the NSWTC | Information and Installation Guide for Small Wind Turbines | Testing | Standards & Labelling | Professional Development & Training | Research | FAQs

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About the NSWTC & the Need for Testing

The Need for Improved Products and Standards.

The National Small Wind Turbine Centre (NSWTC) commenced operation in December 2008 and aims to stimulate the small wind market and industry in Australia by focusing its activities in four activity streams: Testing, Standards and Labelling, Professional Development and Training, and Research. The main activity of the NSWTC will be in providing independent testing services to wind turbine manufacturers but the work in Standards and Labelling is important to improve the quality of products for consumers and to simplify and harmonise standards so that manufacturers can enter export markets.

Historically the market for small wind turbines in Australia has been largely focused on battery charging units for electrification in remote areas. However, in recent times there has been a significant increase in interest for small wind turbines for utility connection in urban and semi-urban areas. This is also the case internationally, where it is reported that the number of small wind turbine manufacturers has dramatically increased in the past few years, particularly in the US and UK. The fastest growing segment of the market is that of residential-scale, grid connected units, between 1 and 10 kW. Similarly in Australia the number of companies developing small wind turbines has also recently risen significantly.

The International Energy Agency (IEA) has expressed concern that not all models of SWTs that are now being produced are reliable or safe (Ruin & Thor, 2006). This is of paramount concern given the proportion of SWTs being deployed in the urban environment in some countries. Large wind turbine manufacturers have to obtain certification for their products and often have to sign a legally binding contract with the purchaser that guarantee a minimum performance level. Small wind turbines do not have to undergo the same stringent certification process and don’t have the same range of standards as the large wind industry. Although there are some standards that have applicability to SWTs, there is a call from SWT manufacturers to improve the standards and make them more relevant. From the point of view of the consumer, there is often confusion over the variety of products on the market and there is a call for a product label to reduce consumer confusion and enable easier product comparison.

Despite the existence of standards, it is estimated that out of the 36 SWT manufacturers that have begun sales around the world, less than 5 are currently certified to any kind of standard. In many cases the only test data available is provided by the manufacturer and there can often be discrepancies between the performance figures stated by the manufacturer and that observed by the consumer (Gipe, 2009) There is a need for independent, third-party testing of small wind turbines to capture key information related to the safety, noise and performance of the turbine.

 

The Formation of the NSWTC at Murdoch University.

Murdoch University has played an important role in supporting the development of the Australian wind turbine industry for over 15 years. Murdoch University had a close collaboration with local manufacturer Westwind turbines (no longer in Australia). Westwind turbines produced the 60kW turbines for Australia’s very first wind farm at Salmon Beach, Esperance in 1984 (check). From 1993 – 2006 Murdoch University assisted Westwind in the development of a range of small wind turbines for the Remote Area Power Supply Systems (RAPs) market. This included the demonstration of the 20kW turbine at the Exmouth Advanced Mini Wind Farm.

Building on this track record, in August 2008 the Research Institute of Sustainable Energy (RISE) at Murdoch was awarded a $1million grant from the Federal Department of the Environment, Water, Heritage and the Arts to establish the National Small Wind Turbine Test Centre. The new Centre augments the existing wind turbine monitoring and assessment resources available at Murdoch University.

The Project Visionary and Technical Advisor of the project, Dr Jonathan Whale, has a long history with wind energy research at Murdoch University and with the international wind energy community. His vision is to build the certification capability to support the Australian small wind turbine industry, increase accessibility of small wind turbines for remote and regional Australia, improve standards and encourage the uptake of small wind turbines in residential areas.

"Murdoch is ideally positioned to lead the way in this area given its 10-year experience in testing wind turbines and links with international standards and testing agencies," Dr Whale said. "As RISE has the only National Association of Testing Authorities (NATA) accredited laboratory for renewable energy power inverters in Australia, the new Centre will be the only one of its kind and will be a one-stop-shop for wind turbine and inverter combinations in terms of certification, standards and training". "By working together with the International Energy Agency, the Centre will test small wind turbines to standard and provide both manufacturers and end users with a design review of the turbine and credible performance data."

(L-R) Prof. David Harries, Director RISE, Prof. John Yovich AM, Vice Chancellor Murdoch University, The Hon. Peter Garrett MP, Dr. Jonathan Whale, Murdoch University lecturer & wind expert. Pictured at the RISE Outdoor Test Area, 12 August 2008.

Minister Garrett said the Small Wind Turbine Test Centre would develop a stronger small wind turbine industry in Australia. "There is increasing interest in small wind turbines for homes and farms, particularly in remote areas. This testing facility will provide consumer confidence in wind technology as well as enhancing our understanding of the potential for this type of technology, not only in remote areas but more broadly as a means of reducing energy consumption and carbon pollution" Mr Garrett said.

To see a video of Peter Garrett’s announcement at RISE go to the YouTube Video "Developing a stronger small wind turbine industry"

References

Gipe, P. 2009, Testing the Power Curves of Small Wind Turbines, [online, March 2009], http://www.wind-works.org/articles/PowerCurves.html

Ruin, S. and Thor, S-E 2006. Summary of IEA RD&D Wind – 49th Topical Expert Meeting on “Challenges of Introducing Reliable Small Wind Turbines, September 2006, Stockholm, Sweden.

 

The Information and Installation Guide for Small Wind Turbines

The Information and Installation Guide for Small Wind Turbines contains information regarding Installing Small Wind Turbines, Small Wind Policy in Australia, Small Wind Standards and Certification, Small Wind Turbine Design and Manufacture, Small Wind Turbines in the Built Environment, and The Small Wind Market.

 

 

Testing

The lack of tested products has been one of the barriers to the growth of the small wind industry. The NSWTC will assist the development of the industry by offering manufacturers affordable, independent, testing of turbines for power performance, acoustic noise and durability. Tested turbines will be awarded a quality/consumer label that will allow potential purchasers to easily compare turbines characteristics, thus enabling the consumer to choose a unit suitable for their specific requirements.

Test Results.

Under Development.

 

Standards & Labelling

IEC/IEA Small Wind Liaison Program.

The recent growth of the global small wind market has meant that standards, testing and certification of SWTs has become a priority and the International Electrotechnical Committee (IEC) and the International Energy Agency (IEA) have joined forces under the banner of the IEC/IEA Small Wind Turbines Liaison Program. The National Small Wind Turbine Centre was nominated by the Clean Energy Council to be Australia’s representative on the IEC/IEA Program.

The IEC/IEA Program consists of collaboration between international small wind experts who meet on a regular basis. These experts represent SWT manufacturers, international testing centres, research centres and certification agencies. The experts are split into two working groups, the IEC TC-88 MT2 working group and the IEA Task 27 group. Many members of the IEC/IEA Program are involved in both working groups. The first meeting of the IEC/IEA Small Wind Turbines Liaison Program took place in Madrid, Spain in February 2008. A meeting is scheduled to take place in Australia in December 2010.

IEC/IEA Small Wind Turbine Liaison Program Meeting at Germanischer Lloyd’s WINDTEST, Kaiser-Wilhelm-Koog, Germany, March 15- 17, 2010.

 

IEC MT2 Working Group.

The IEC TC-88 MT2 working group aims to revise the international small wind standard IEC 61400-2 (2nd Edition, 2006). The standard relates principally to the structural design requirements of small wind turbines and there is a need to incorporate into the standard some of the latest developments in small wind turbines. The MT2 group is working toward producing a 3rd edition of the standard that will expand upon the requirements of small wind turbines across a range of different topics. Some of these topics include requirements in the area of performance (power and noise), requirements of SWTs in harsh environments (cold climates, cyclones) and requirements in urban environments (building-integrated, roof-mounted).

IEA Task 27.

The IEA Wind RD&D tasks aims to advance research of less mature topics in wind energy. The results of this research can then form guidelines that can be incorporated into later editions of wind standards. Approval from the IEC Executive Committee for the IEA Task 27 proposal “Development and Deployment of a Consumer Label for Small Wind Turbines “ was granted in October 2009 and the first official IEA Task 27 meeting took place in Tokyo in December 2009. One of the main activities in Task 27 is to develop a consumer label to aid consumers in making informed decisions over the purchase of SWTs. The label is being trialled by different testing bodies around the world, including the National Small Wind Turbine Centre in Australia. Task 27 will run until December 2011 and a summary of the Task can be viewed at http://www.ieawind.org/Summary_Page_27.html

 

Professional Development and Training

Trade Training.

Under Development.

Professional Courses.

Under Development.

 

 

Research

Recent Publications.

Whale, J. and Brix, B., 2009 The National Small Wind Turbine Centre: Activities in Standards and Labelling, Proceedings. 47th Australian and New Zealand Solar Energy Society (ANZSES) Solar09 Conference, Townsville, September 2009.

Pascale, A., Whale, J. and Doepel, D. 2009 A review of State policy on small wind in WA, Proceedings. 47th Australian and New Zealand Solar Energy Society (ANZSES) Solar09 Conference, Townsville, September 2009.

 

 

Frequently Asked Questions (FAQs)

Q. How does a wind turbine work?

A. The job of a wind turbine is to capture energy in the wind and convert it to electrical energy. The kinetic energy in the wind (mass of the air having speed) is captured by the blades through lift over their aerofoil section. This work is transferred by the blades to generator as mechanical power. This mechanical power does work on the windings within the generator and induces an electrical current to flow to the load.

Q. What size wind turbine would I need for my requirements?

A. The capacity of turbine required depends on the intended use. In order to size a turbine with any accuracy, knowledge of the wind resource at the site is required. This is usually done by installing wind monitoring equipment and recoding the wind strengths preferably over a period of one year or more. For a standalone system the turbine must be adequately sized for the electrical load, with consideration for other generation components (i.e. generator, photovoltaics). The size of a grid connected system is primarily determined by the amount of energy you would like to feed into the grid. Your average household consumption, taken from your electricity bill, will give you a good starting point for determining your particular requirements. Local area planning laws should always be consulted firstly as this may restrict the size and or tower height of the turbine you are planning to install. The swept area of a turbines rotor is directly proportional to the energy available for capture at a given wind speed. The value rotor swept area / generator capacity is worth considering when you have wind data for your site. Turbines with higher values are usually better suited to lower wind speed sites.

Q. Is my site windy enough?

A. The amount of energy a wind turbine can capture is directly related to the wind speed working on the blades. Due to the relationship of wind speed and power in the wind being a cubic function (i.e. double the wind speed = eight times the power) small increases in average wind speeds can pay large dividends in annual energy generation. Therefore to predict, with reasonable accuracy, the amount of energy a turbine will generate it is important to know what the average wind speed is at the location where the turbine is proposed. Ideally wind monitoring equipment will be installed at the location and at the hub height of the proposed small turbine and the wind speed be recorded for a full year. The annual average wind speed can then be used to calculate the annual generation of the turbine. In general a site needs to have a mean annual wind speed of at least 5m/s for a small wind turbine to be cost competitive with other technologies such as photovoltaics.

Q. Are wind turbines reliable?

A. Well designed and manufactured turbines are indeed very safe and reliable if they are installed and maintained as per the manufacturer’s guidelines. However, as with all products, there is a wide variation between the design and build quality of different manufacturers. The small wind turbine industry has enjoyed rapid market growth in the last few years and this had led the swift increase in the number of manufacturers marketing their products worldwide. For this reason it is recommended to choose a product that has been independently tested for power performance, acoustics and durability. Ideally the turbine should be designed and preferably certified to the relevant international standards for small wind turbines (IEC61400-2). Currently there is no mandatory requirement for turbines marketed in Australia to be independently tested or certified, so it really is a case of ‘buyer beware’. Independent testing is usually done in accordance to the relevant international standards and involves at least six months of continual operation in a wide range of wind conditions. Since the testing is done to a standardised method, all power performance and acoustic results can be compared between different turbines thus making comparison easier. Turbine reliability can be affected by poor installation practices or adverse environments such as high turbulence, sea spray etc.

Q. What height tower should I choose?

A. Wind speed increases with height above the ground due to the effect of drag on the ground, exacerbated by obstacles (trees, buildings, hills etc) which tend to further slow the wind close to the ground. The greater the number and height of obstacles, the larger the slowing effect. This results in a higher elevation being required to achieve the same wind speed compared to wind flowing over a smooth terrain. The effect of surface roughness on wind speed can be calculated using the “power law” equation.

Therefore a turbine installed in an area with numerous obstructions, such as urban areas, will benefit significantly from a taller tower. For example increasing a tower height from 10m to 20m in a suburban area will increase the wind speed by approximately 20%, thus providing an increased power generation potential of over 70%. Put simply, the higher then the greater the wind strength. However, increasing tower height does increase the cost of the tower and usually the cost of its installation. Also there may be height restrictions imposed by the local building regulations at the proposed site. Additionally turbine manufacturers may only offer a few different height towers for each model manufactured. In practice there may not be many options to choose from and the decision of what height tower to use can usually be quickly assessed in terms of cost, potential increased energy harvest and local regulations.

Q: What types of towers are available? Which is best?

A. There are two broad classes of towers that are often used with small wind turbines –guyed and self supported. As the name implies, guyed towers are supported vertically by one or more sets of guy wires. Whereas self-supported towers are attached to a heavy foundation to support the tower. There are advantages and disadvantages of both designs and the best choice for a potential installation will most likely come down to aesthetics and land area required. Guyed towers require a larger “footprint” area than self supporting towers due to the guys that are generally installed at a radius of approximately half tower height. A concrete foundation is required at the base of each guy wire and also at the base of the tower. Due to their inherent design, guyed towers optimize both tower and footing materials and thus are generally more slender than free standing towers and require less concrete for their footings. It is worth noting that guyed towers may be designed so that they can be easily lowered to ground level for installation and maintenance without the need for cranes or cherry pickers. Free standing towers are often chosen where space constraints prevent the use of guy wires or aesthetically, where a less cluttered look is preferred. Some free-standing towers may be designed with the ability to tilt to the ground for servicing, however it is more common that a cheery picker is required to elevate the service person to hub height. Most towers are constructed from tubular steel and this is usually hot dip galvanized for corrosion resistance.

Q. How much will a wind turbine cost?

A. Unlike photovoltaics economy of scale applies to small wind turbines. For example a 10kW turbine would be less than twice the cost of a 5kW unit. However with photovoltaics doubling the capacity would usually yield twice the cost. Similarly the installation cost of a small turbine is not linear with capacity. This is due to the mobilisation cost of machinery required for civil works such as a backhoe for foundations or a crane for erecting the tower. As a rough guide a 1kW grid connected turbine on a 15metre tall tower could be installed for approximately $15,000. A 5kW unit would cost in the vicinity $35,000. However it should be noted that product quality does vary which is often reflected by price.

Q. Are wind turbines a good economic investment?

A. There is an increasing global trend in the price of energy, including electricity. This is driven by our increasing demand, governments taxing fossil sources and the depletion of accessible fossil fuel deposits. At current prices the payback period for small wind turbines varies from 5 to 20 years. However if the rising cost of energy is forecast these periods will be reduced. The wide variation in payback period is due to a number of reasons, but more specifically depend on wind resource, cost of turbine/installation and of course the cost of displaced energy. It is quite a simple task to calculate the rate of return from a wind turbine if you have reliable wind data for the site and dependable performance data for the potential turbine. Larger turbines tend to have a lower cost to capacity ratio making them more cost effective. Any rebates/grants available will reduce the initial investment and so reduce the payback period. The final economic consideration is the interest on the value of the installation. This point is best illustrated if monies are borrowed for the installation.

Q. How does a grid connection work?

A. Gross metering is where every unit (kWhr) of energy the wind turbine produces will be metered and subsequently receives the tariff, this is irrespective of the household demand. Net metering, on the other hand, only records the amount of energy the turbine produces in excess of the household demand. The table below shows the State and Territory feed in tariffs and allowable generation capacity.

Table 1: There is no Northern Territory-wide feed-in tariff, but through the Alice Solar City project Alice Springs residents can access a gross feed-in tariff of 45.76c/kWh for 2kW max system (capped at $1825 per annum) Source: Energy Matters 63-69 Market Street, South Melbourne, Victoria, AUSTRALIA 3205 http://www.energymatters.com.au/

Most wind turbines generate electricity in three phase “wild AC”, being variable voltage and frequency. This is first rectified to direct current (DC) and then fed into an inverter. More modern, higher efficiency wind system inverters have Maximum Power Point Tracking (MPPT) whereby performance is optimised by controlling the rotor speed to maximise aerodynamic efficiency.

Q. Should I install a wind turbine or solar panels? What’s best for me? How does wind energy compare to solar?

A. If the motivating factor is economic then the cost of electricity generated (over the life of the system) will be the determining factor. Estimating the power generated from a solar photovoltaic system is a relatively simple procedure however this is not the case with wind systems. In order to calculate the estimated power production of a wind system the wind resource must be accurately known at the site and height of the potential installation. (See Q. Is my site windy enough). For remote area power systems (RAPS) there may be a benefit from wind supplying charge during the night thus reducing the discharge cycling of the battery bank. Similarly wind and solar may work well in conjunction with each other. Local council requirements may also restrict the height of wind turbine towers or their placement thereby constraining installation options. For this reason, even though wind power may be the best economic option, local regulations may enforce a less than optimal tower height or unfavorable location thus reducing potential generation capacity.

Q. Are wind turbines noisy?

A. This depends on the wind turbine design. In general, a well designed turbine is not very noisy, however the level of noise and its annoyance is a subjective matter. Reputable manufacturers will be able to provide independently tested noise data which may be used to estimate the level of noise at a distance away from the potential turbine installation. Most of the noise emitted from a small wind turbine is produced by the blades and to a lesser degree the generator (or gearbox if there is one). The magnitude of noise is primarily dependent on the rotational speed of the rotor hence depends on wind speed. It is worth noting that background noise also increases with wind speed and often this muffles the noise from the wind turbine. Council requirements often dictate how close neighbors’ homes can be located from a noise emitting source and\or the magnitude of the noise.

Q. Can I mount a wind turbine on my roof?

A. Some manufacturers offer turbines that are designed for roof mounting. However, many wind turbine professionals believe that mounting a turbine on a building is a risky decision due to the potential of transmitting noise and vibrations into the building structure and due to the turbulent airflow usually encountered over a structure often limiting performance and potentially shortening the turbine design life. Nearly all roofs have a different design, shape or orientation to predominant winds, therefore the wind flow will vary significantly from one roof to the next. This makes finding an adequate location potentially difficult and may require significant investigation with wind monitoring equipment to identify if a suitable location exists. As with any potential wind turbine site it is advised to assess the wind resource and this recommendation is even more pertinent with roof mounting.

Q. Will it impact wild life?

A. Flying animals are obviously the most at risk when discussing the potential impact of wildlife. Internationally there have been many scientific reports that have investigated the impact of commercial scale wind turbines on birds. In the US it has been reported that commercial scale wind turbines cause the direct deaths of only 0.01% to 0.02% of all of the birds killed by collisions with man-made structures and activities. The majority of birds are killed by; residential and commercial windows, power lines, cars, trucks and of course domestic animals. There is no knowledge of a report that has investigated the impact of small wind turbines. However, it is believed that the probability of avian strike may be lower than the already low estimate of commercial scale turbines. This is due to the rotational speed of the blades of small turbines, making them more visible for most animals.