Small%Wind%Site%Assessment%Supplement Abriefexplanation … · 2012. 3. 15. · Developed!as!part!of!the!OEHfunded!Pilot!“Small!wind!siteassessment”Course.! August!2011! Basedonthe!Midwest!Renewable!Energy!AssociationSmall!WindSupplement

Developed as part of the OEH funded Pilot “Small wind site assessment” Course. August 2011 Based on the Midwest Renewable Energy Association Small Wind Supplement.

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Small Wind Site Assessment Supplement: A brief explanation of your small wind site assessment

1. Wind Basics When talking about generating energy from the wind, there are some basic principles that need to be understood:

• The site needs to have a good wind resource; otherwise the wind turbine cannot work at its designed efficiency and will not produce the expected amount of power. A good wind resource includes a sufficiently high wind speed and minimal turbulence. Details about what makes a good wind resource will be discussed later in this document.

• The surrounding terrain should be relatively free of clutter; wooded and urban areas are considered very cluttered. This is why you see wind farms in wide open fields and in the water.

• Typically, wind turbines have two or three blades. Regardless of the number of blades on a wind turbine, the energy generated is directly proportional to the “swept area”; the area that is encompassed by the blades when they are spinning. Power is actually proportional to the square of the blade length: P ~ (Blade Length)². Increases in blade length significantly increase the power output.

• Wind turbines need to be on tall towers. Because of the friction between the wind and the earth, wind speed increases rapidly with increasing distance from the ground, especially in the first 20m. Also, obstructions around the turbine, such as trees or buildings cause turbulence, which not only reduces the efficiency of the turbine; it also shortens its life due to additional wear and tear. A general rule for tower height is that the bottom of the turbine rotor should be at least 10m above the tallest obstruction within 150m or the nearby prevalent tree height. For trees, this means the mature tree height over the 20 to 30 year life of the turbine, not the tree height when the assessment was done. For residential or small business sized wind systems, towers of 30m or 36m are usually optimal.

• The longer the distance to connect to the grid, the higher the cost due to the labor cost of trenching, the cost of the longer wire, and because a larger diameter wire (more expensive) will have to be used to minimize line losses. While the viable grid connection cost of each project varies, small wind projects turbines located 500m from the grid (or from the rest of the Stand Alone Power System [SAPS] for an off grid system) are very unlikely to be cost effective.

• The site for the wind system must be accessible, either for a crane or with space enough to tilt up a tower. Most wind systems (except tilt-‐up towers), even residential sizes, need a crane during installation to raise the tower and/or to lift and place the turbine on top of the tower.

• Currently, the majority of small wind systems in Australia are part of a Stand Alone Power Supply (SAPS) system, including a large battery bank, a generator, and other components. These are also known as Remote Area Power Supply (RAPS), or simply ‘off-‐grid’ systems. Excess energy that can not be used on site or stored in the


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batteries is ‘dumped’ (converted into heat) to prevent damage to the wind turbine or batteries.

• For grid connected systems, the electricity generated by the wind system will be used directly by the loads at the site and that any excess will be exported to the utility power grid. When the utility grid goes down (during a power outage) the wind system also shuts down, for safety reasons, and no energy will be delivered. This is not a significant concern in areas where power outages are rare.

2. Wind System Siting Considerations a. Prevailing Wind Direction and Turbulence The turbine should be located where it can intercept the good quality wind, based on the prevailing wind directions at the site and on the locations of the highest obstructions within 150m. More intercepted wind means more electricity produced. Obstructions, such as buildings, rough terrain, and tall trees disrupt the flow of the wind and create turbulence. Turbulence not only reduces the amount of energy that can be extracted, but also creates a harsher environment for the wind turbine, especially the rotor blades, and this may shorten the life of the system. The best sites for wind systems are on wide open land and on the tops of smooth ridges and large bodies of water. If wide open land is not available, it is best to site the turbine where obstructions do not block the wind from prevailing wind directions and/or significantly above the tallest obstruction; so the tower height must be sufficiently tall to place the rotor above the turbulence. Tower heights are addressed later in the report. b. Additional Factors There are several additional factors to be taken into account when siting a wind system. The primary requirement is that the turbine is able to intercept the most wind with the least turbulence as stated above. The other considerations include:

• Length of the wire run to the inverter or battery bank – the shorter the better for cost and for line losses.

• Convenience of location to the property owner -‐ to make sure that the wind system does not interfere with day to day activities or impact their lifestyle too much.

• Accessibility to the system by a crane -‐ which is needed for raising the tower and placing the turbine on top of the tower and in case of major maintenance or repair.

• Accessibility issues for installation and maintenance include steep ridges, low overhead power lines, dense woods, crossing streams, etc.

• Local zoning regulations for setback distance requirements from roads, overhead utility lines, and property lines.

Based on these considerations, the assessor will determine the best location(s) for a wind system on the property.


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3. Wind Resource a. Wind Map When considering a wind system it is important to know what kind of wind energy resource is available. Wind maps for the majority of the Australia are available through state or federal governments. Several private companies, such as 3-‐Tier, also offer on-‐line estimates of wind energy resources. Companies that specialize in developing Geographic Information System (GIS) databases of wind information develop such maps. These databases include wind speed information for the state compiled from the historic climatological data of weather satellites and stations, airports, monitoring towers, military sources, etc. They may also include wind directional data, elevation and topography data. Average annual wind speeds are provided in these databases at various heights typical to wind turbine hub heights above ground, and the maps have a resolution ranging from 90m to 3,000m. Lower resolution wind maps are available on some state and federal government agency websites, including NSW Department of Trade and Investment (NSW), Sustainability Victoria (Victoria), the Department of Climate Change and Energy Efficiency (Australia), etc. In order to estimate the wind energy resource for the sites and tower heights recommended in the report, the mean wind speed at the latitude and longitude of the site from the nearest map height above hub height is retrieved from the wind map data base. This value is then extrapolated down to the tower heights recommended in the report. A copy of the appropriate wind map and a close up image of the site specific wind map should be included with the assessment report. b. Weather Stations Weather stations such as the Bureau of Meteorology, also record wind speed, however the height of these wind monitoring stations (typically 10m) does not provide accurate indications of wind speeds and so can not be used for extrapolation of wind speeds to a wind turbine hub height. c. Topography The topography around a site can affect the wind flow. The tops of hills and wide open farmland are obviously better sites for wind systems than sites located in low spots or down in valleys. Small changes in elevation can sometimes be allow, or require, changes in tower height. For example, if an assessor specifies two potential sites on a property and one of the sites is 6m higher in elevation, then, all other factors being equal, the owner may have the option of using the lower site and installing a 6m taller tower than that required at the higher site to get the same output from a wind turbine. The site assessment report includes two topographical maps. The first is a close up of the property, which may show local elevation variations on the property. The second is a smaller scale map (i.e. the map shows a larger area), which reveals how the contours of the surrounding area may affect the wind at a particular site.


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d. Wind Shear Wind speed increases with rising elevation above ground level. At ground level, friction caused by the interaction of the wind with vegetation, trees, buildings and topography of the land decreases the wind speed. At higher elevations above the ground, the wind moves unimpeded and its speed increases. The power output from a wind turbine is proportional to the wind speed cubed (e.g. wind speed × wind speed × wind speed) so small increases in wind speed produce large increases in power output. If the wind speed and/or wind direction is not consistent on the blades as they spin from the lowest position to the highest, then the energy in the wind is not being converted efficiently and it also imposes more stress on the wind turbine. The change in wind speed with height above ground is called wind shear and is caused by both the natural friction of the wind with the ground (ground drag), and by turbulence which is created when the wind encounters local obstructions such as trees, buildings, etc. It is important to note that closer to the ground (under 20m) the wind speed changes very rapidly (high wind shear) with minor changes in height. As height increases above 20m, the rate at which the wind speed changes with increased height is reduced (lower wind shear).

For example, the graph below shows how the wind speed changes as the height above the ground increases, at a specific site (it is important to note that the actual wind shear and wind speeds will vary considerably from one site to the next).

Graph 1. Wind Shear Graph form Danish Wind Association


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Therefore, adding height to the tower reduces the wind shear on the blades and will allow the turbine to operate more efficiently and with less maintenance. The larger the turbine and the longer the blade length, the more critical it is to have the rotor further away from the ground onto the more vertical (and more consistent) part of the wind shear curve. The wind shear exponent describes the increase in wind speed with height. Shear value reflects the macro effects of terrain more than 50m from the wind turbine location. The table below shows the typical wind shear exponent (alpha values) as a function of the site’s surface characteristics.

Table 1. Wind Shear Exponent and Surface Characteristics

Surface Description Wind Shear α

Smooth Hard Ground, Lake, or Ocean .20

Level country with foot-‐high grass Tree lines > 300m away

0.25

Level and uniform open terrain with crops with occasional trees and buildings 150m-‐300m

0.30

Terrain is open with scattered Trees/buildings <150m 0.35

Terrain is less open, not densely treed; Trees/buildings <150m; or, Mixed densely treed areas & open areas; Tree lines > 150m away

0.4

Mixed densely treed areas & farm fields, Trees/buildings <150m 0.45

Densely Wooded 0.50

Urban areas with tall buildings 0.60 assumed but cannot tell without

monitoring

While wind maps do take into account wind shear values based on the general ground cover and topography of a local area; one of the purposes of the site visit is to estimate a more site-‐specific value. The estimated wind shear factor value should be specified in the site assessment report. e. Turbulence Turbulence is created when the wind’s flow is disrupted by encountering local obstructions such as trees and buildings. If a wind turbine is located in turbulent flow, it cannot operate efficiently, resulting in lower than expected energy outputs. Additionally, increased wear and tear on the turbine blades can significantly reduce turbine life. To avoid this turbulent flow a wind system can be placed upwind of the obstacles towards the prevailing wind direction, or a far enough distance away from the obstructions (20 times the obstruction height), or on a tower that is tall enough to get the rotor clear of the turbulence. The “turbulence intensity (TI) factor” is a parameter that indicates how gusty a wind site is. The following are the common TI factors used in assessment reports.


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Site Quality Terrain Turbulence Intensity Factor

Good Well Exposed 15%

Average Some Ground Clutter,

Scattered Trees, Buildings

20%

Poor

Many Trees or Buildings, Lower Elevation than Surroundings

25%

Very Poor Urban or wooded 30%

In the site assessment report the assessor should determine a TI factor based on the site specific obstructions. f. Estimating Wind Speed at Tower height Once the estimated mean wind speed is retrieved from the wind map, or the measured mean wind speed is derived from monitoring, the wind speed at the recommended tower heights may be estimated by extrapolation using the following equation (ref. The Wind Power Book by Jack Park): V = (H/H0)aV0 where: V = the wind speed at the desired height (the tower height) Vo = the wind speed at the map height Ho = the height at which the map mean wind speed was measured or estimated (usually 40

to 80m) H = the tower height(s) specified in report (turbine hub height) a = the wind shear exponent The values for the average annual wind speed for the site at the recommended tower heights will be given in the site assessment report. These will be the wind speeds used to calculate the average annual energy output of the potential wind turbine options. g. Wind Rose Because most sites will have some sort of obstructions, either trees or buildings, the direction(s) of the prevailing winds become an import factor in determining where to site a turbine. A diagram called a wind rose is normally available to site assessors from a number of potential sources, including wind maps and BoM data sets. A wind rose diagram illustrates the prevailing wind directions at a site and the relative strength of the wind from each direction. For the optimal turbine performance it is best to capture the winds coming from all directions, but if there are tall obstructions at the site, the wind rose helps to determine where to position the wind system so it will be upwind of these. The site assessment report should contain the appropriate wind rose for the site. Visual indicators such as “tree flagging” and wear and tear on one side of a building can also


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be signs of a prevailing wind direction at a site. Tree flagging is indicated by the deformity of tree growth on one side of the tree. The lack of these visible signs does not imply that there is not a good wind resource at a site. h. Displacement Height Due to the friction created by surface of the earth, the wind speed at ground level is effectively zero. At some sites, there are so many obstructions in the immediate surroundings that they create, in effect, a new “ground level”. This is common in urban areas or in densely wooded areas where the average building or tree height appears to the wind profile as the ground level, which means that the wind shear curve in shown in the graph above begins not at ground level, but at this new “displacement height”. In these cases the site assessor must adjust the wind speed accordingly, resulting in lower, but more accurate, wind speeds and energy production estimates for wind system performance. Displacement Height relevance should be determined prior to the site visit and confirmed on the site visit. If wind is displaced at the site, the site assessor will determine the displacement height and use the displacement height in the wind speed calculations.

4. Wind System Towers There are several types of towers that can be used for residential size wind systems 20KW and under: a. Guyed Lattice towers

• Usually have three sets of guy wires. • Least expensive type of tower. • Guy wires holding up this tower have a radius of 50%-‐ 75% of the tower height from

the base. • Requires climbing the tower for maintenance. • Usually installed with a crane

b. Tilt-‐up towers

• Usually made from tubular steel sections • Have four sets of guy wires. • Usually cheaper to purchase and install than guyed lattice towers. • Can not be climbed so must be lowered and raised for all maintenance • Guy wires have a radius of 40% -‐ 75% of the tower height from the base. • Requires relatively flat terrain for the length of the tower in at least one direction

from the base of the tower, in order to lower the tower to the ground. This is not a task to be taken lightly, and requires 2-‐3 trained personnel (owner can be trained). See photo below.

• Requires a large area that must remain free of permanent obstacles for the life of the system.

On the above guyed and tilt-‐up towers, guy wires are not visually intrusive when viewed from a distance. c. Free-‐standing towers – Lattice and Monopole

• Have no guy wires.


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• Small footprint of approximately 10% of the tower height depending on the strength and gauge of the tower steel. There is less of a footprint with a heavier duty tower. Good for tight spaces.

• Significantly more expensive than guyed or tilt-‐up; contains more steel and weighs more than the other types.

• More visible on the landscape. • Requires climbing the tower for maintenance. • Requires a substantial foundation. • Installed with a crane. • Normally, only free-‐standing towers are used for larger sized wind systems, 35kW to

100kW. • Monopoles are usually only used for larger turbines since they are significantly more

costly than the free-‐standing lattice towers and require an even larger and deeper foundation.

d. Other tower variations -‐ such as tripod towers and centre pivot towers

• are much more expensive than the above options

Figure 1. Tower Figures

Freestanding Guyed Lattice Guyed Tilt-‐Up Monopole


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5. Minimum Tower Height The minimum tower height determination is a critical part of a wind site assessment. One of the biggest mistakes that can be made when installing a wind system is to install the turbine on a tower that is too short for the site.

The goal is to position the entire rotor (the area swept out by the blades) in an area of good quality wind. If the wind speed and/or wind direction is not consistent on the blades as they spin, the energy in the wind is not being used effectively and it imposes more wear and tear on the turbine, resulting in more maintenance and a reduced turbine life. By increasing the tower height, the rotor can be positioned above the most severe effects of wind shear and turbulence caused by obstructions and the local ground cover.

To ensure that the rotor is above the worst of the wind shear and turbulence, it is suggested to use a minimum tower height of at least 10m above any obstacles within 150m, or 10m above the prevailing mature tree height for the area.

The site assessment report should recommend the minimum tower height, for each recommended location, based on the surrounding obstructions and the prevailing wind directions. Keep in mind that this is the minimum height. Wind speed increases with increasing distance from the ground, so a taller tower will increase the wind speed at the turbine height. The energy generated by a wind turbine is proportional to the cube of the wind speed, P ~ (Wind Speed)3, so any increase in wind speed makes a significant increase in power output. For this reason, tower heights taller than the minimum that is recommended in the assessment report should always be considered.

Renewable Energy Credits based on estimated production. So, the cost of increasing tower height will be at least partially offset by the increase in the amount of the incentive, and the owner will enjoy higher energy outputs for the life of the system.

Towers often come in heights that are multiples of 6m , and heights of 24m, 30m, and 36m are commonly installed in locations which have shelter belts, treed areas, and rolling hills. A


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few turbine manufacturers offer slightly different tower heights such as 32m and 38m, and if applicable, these will be noted in the wind assessment report.


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6. Wind Turbines Currently there is no internationally recognised standardised rating system for small wind turbines (although this standardisation is in progress).

For example, visit the Small Wind Certification Council webpage for the latest updates:

www.smallwindcertification.org/

Some manufactures rate their wind turbines based on the output at 11 m/s (25 mph), while others may rate their turbine at 18m/s. For that reason a turbine rated a 6kW may actually produce more energy than a turbine rated at 10kW at the same location, so it is important to look at a turbine’s annual energy output (AEO) rather than its name plate rating. Until a standard rating is adopted, your assessor should rate turbines based on their output at 11m/s.

One good indicator of energy production is turbine rotor diameter. The available power in the wind changes proportionately to the blade length squared so usually the turbine with the longest blades will generate more energy at a given site.

In the US, most states or utilities offering incentives for wind turbines will only fund turbines that have a proven track record to ensure that the customer is getting a reliable wind system. The following is a list of turbines currently funded by some states offering incentives. Note Australia does not yet have a list of approved wind systems, but the Clean Energy Council is working towards this.

All wind systems require preventative maintenance and an inspection twice every year. Generally, turbines with gear boxes require more maintenance than the others because there are more moving parts. For a very helpful resource that compares the performance of reliable wind systems, visit the website of Home Power magazine and look up their yearly articles on how to buy a wind system.

2009: How to Buy a Wind-‐Electric System 2010: Wind Generator Buyer’s Guide 2011: Is Wind Electricity Right for You

The US National Renewable Energy Laboratory also has up to date information on small wind system testing:

http://www.nrel.gov/wind/smallwind/ The assessor based on the site conditions should determine the best turbine options for a specific site and the desires of the client as discussed during the site visit.


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7. Wind System Outputs Once the mean wind speed at the recommended tower height(s) is estimated by the assessor, the expected power output of the various turbines recommended for a client can be computed. The estimated energy outputs of a turbine can be predicted based on a manufacturer’s power curve for their turbine. A power curve shows how much energy a turbine will produce at varying wind speeds. The outputs are calculated using software such as the “7th Wind Turbine Performance Model”, an Excel spread sheet developed by Seventh Generation Energy Systems and used by US State Public Benefits renewable energy programs (www.seventhwindsoftware.com/pages/about.aspx). The inputs for the software model include:

• the elevation of the site • estimated mean wind speed from the wind map or other source • the estimated distribution of wind speeds • estimated wind shear • estimated turbulence intensity, expressed as a percentage • the tower height • the manufacturers’ power curve for the turbine • the turbine rating at 11 m/s (25 mph)

The turbine’s calculated energy output is also de-‐rated by 5% if it is an inverter-‐based machine. In some cases in the US, the following components are required as part of the wind system to make verify the actual performance of the wind system and compare it to the site assessment. While this has not yet been a requirement in Australia, it is very good practice for any wind system installation, as this enables the customer and installer to accurately monitor the performance of the system based on the actual wind speed data recorded. Wind Speed Logger and Anemometer: A cup anemometer is mounted on the tower one rotor diameter below the top of the tower. The anemometer should be installed on at least a four foot boom in the approximate direction of the annual prevailing winds and be connected to a wind speed data logger of the owner's choice. System Performance Meter: A kilowatt-‐hour interval meter are installed between the inverter and the AC circuit breaker for the system. The “Turbulence Intensity Factor” and the “Wind Shear Factor” are both determined by the site assessor based on the obstructions and ground cover at the site, and are included in the site assessment report. The assessment report will provide a table of the estimated annual outputs for a selection of wind turbines for the wind system site(s) identified on the property. The wind speeds and turbine output values presented in the site assessment are computed using the best tools available to the assessor at the time; however, they should not be interpreted as a guarantee of the average annual wind speed or the average output of a particular wind turbine at your site.


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8. Up-‐front subsidies and Revenue Incentives Some state and federal programs offer incentives for installing renewable energy systems. These incentives may reduce the up front or overall cost of a wind system, provide an ongoing income stream, and/or reduce your energy expenditure. Your site assessor should include a description of the incentives available for you in your site assessment report and you can also check the relevant websites of state and federal government agencies for more information. a. Selling the energy from your wind turbine Each state has a cap on the size of the turbine eligible for Feed in Tariffs. Unfortunately, at this time, while most states in Australia offer Feed-‐n Tariffs for solar energy, few offer Feed-‐in tariffs for wind energy.

• Under a gross metered feed-‐in tariff (such as that previously available in NSW), all

energy produced receives a fixed payment per kWh, regardless of the energy used on site by the owner.

• Net metering feed-‐in tariff: States can also have net feed-‐in Tariffs where, for all

energy generated, that is used on site at the time is treated differently to excess which is exported to the grid. Generated energy used on site is effectively worth the avoided cost of not importing that energy from the grid. Energy exported to the grid is eligible for the FiT, which may be higher than the value of energy used locally.

• Power purchase agreements: Where no Feed-‐in Tariff is available for wind turbines,

or for turbines that exceed the maximum capacity eligible for a FiT, a Power Purchase Agreement will be required. A PPA is a contract that provides the owner of the renewable energy generator with wholesale value for any electricity that is put back on to the grid. This will usually be much less than the value of the retail cost of energy.

The assessor should note which utility is servicing the site, and who the customer’s current retailer is. b. The Small Scale Renewable Energy Scheme and Solar Credits Scheme. The Renewable Energy Target (RET) scheme was established to encourage additional generation of electricity from renewable energy sources to meet the Government’s commitment to achieving a 20% share of renewables in Australia’s electricity supply in 2020. As of 1 January 2011, the Renewable Energy Target was split into two parts, the Large-‐scale Renewable Energy Target (LRET) and the Small-‐scale Renewable Energy Scheme (SRES). Each Small scale Technology Certificate created from an eligible energy source can be sold for to liable parties (energy retailers) via a clearing house.


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One STC is defined as: 1 MWh of renewable electricity deemed to be generated by small generation units. The owner of a small wind system is an eligible party to create, and sell STCs . Support to households, businesses and community groups that install solar panels, wind and hydro electricity systems is boosted by Solar Credits Scheme. Solar Credits work by multiplying (by three) the number of STCs created by these systems for the first 1.5 kilowatts (kW) of capacity installed for systems connected to a main electricity grid and up to the first 20 kW of capacity for off-‐grid systems.


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9. Costs The installed cost for a wind system includes the all the materials, labour and related costs for installing a “turnkey” wind system. This includes all the costs that go into having the foundation for the tower and the guy wire anchors poured tower assembly, crane rental for raising the tower and attaching the turbine (if required), trenching, installing the balance of plant (BOP -‐ inverter, switching, etc) components, and all wiring. You may be able to save on some of these costs by doing some of the work (e.g. tower assembly, trenching and excavation), where you have the tools and skills to do this yourself. These options should be discussed and/or arranged with your installer. Note, however, that some incentive programs may not allow owner installation, and this should be researched as well. The installed cost for a wind system can vary widely because of the many factors that must be accounted for depending on the site. These factors include, but are not limited to:

• Soil Type – affects the size and type of foundation • Tower type and height • Distance from the installer’s place of business • Wire run length • Excavation and trenching difficulties • Accessibility issues – open or cluttered, flat or hilly, wooded, fences, crane

difficulties, hilly areas, wet soils, etc. • Choice of make, model and system type

For this reason the costs in assessment reports are ballpark cost estimates and should not be considered as any sort of bid. Contact installers in your area for actual quotes. Other Financial Considerations:

• Maintenance: In addition to installation costs, the owner of a wind system should expect to set aside funds for ongoing maintenance. This amount may not be required every year, but down the road replacement parts may be needed, e.g. new blades or electronic components, and even the most robust wind turbine will typically need at least one overhaul during the course of its 20+ year design life. Your installer should be able to advise you on an approximate cost for annual maintenance, but a good estimate is normally about 1-‐3% of the installed cost per year. Some maintenance can be performed by the system owner. The installer may offer a service contract, which may also be linked to the warranty.

• Insurance: You will need to check if your insurer covers damage caused to (or by) the wind turbine in the event of a storm or accident.

• Loan interest: It is common for turbine manufacturers and/or hence installers, to ask for a down-‐payment to begin turbine and tower manufacturing processes. The delivery times for turbines may vary from weeks to months from the time of down payment. Most incentives can only be received after the project is complete; therefore, if a turbine owner takes advantage of a loan to finance their project, there may be interest payments from the time of down-‐payment until project completion. One option for protection against extra interest charges due to late delivery is for the installer to confirm a delivery date and request that if that date is not met, compensation will be made for additional interest costs or other out of pocket costs incurred.


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10. Other Considerations a. Soil Type The type of soil at a site will determine the level of difficulty of installing the tower foundation and/or anchors. If a site has shallow bedrock or very sandy or marshy soil, the foundation cost will be affected. For this reason the installer may request a soil test. b. Aircraft Small wind turbines should be located to avoid flight pathway obstruction. The relevance of this issue will depend on the proposed height of a small wind turbine, and its proximity to an airport. It may also be a consideration where a small wind turbine is installed in areas where aerial agricultural spraying is undertaken. The Civil Aviation Safety Authority is responsible for aircraft safety and your site assessor will advise of any considerations that need to be made for a small wind turbine at your site. c. Electrical Supply and BOP In order to connect a wind energy system to the grid, the power produced by the system must be meet the strict safety and power quality requirements of the distribution business.. Electronic and electrical components, including the inverter, the wiring, disconnect switches, circuit breakers, etc, are called the Balance of Plant (BOP) components and usually reside next to an existing switch board in the house or garage. Components are often located inside a building. Your assessor will examine your main switch board or to determine the capacity of your supply and the availability of circuit breaker/fuse spaces for connecting the wind system. The installer, or the installer’s electrician, will need this information and may recommend a service upgrade if necessary to meet the various electrical standards and regulations. d. Zoning Because wind systems are a relatively new issue for planning authorities, some municipalities have no zoning ordinance for wind systems while others may have old, overly restrictive ordinances. Common, acceptable restrictions include a setback distance equal to the extended height of the wind system from roads and property lines. The site assessor will often try to site the wind system to meet this common setback restriction. In NSW there are state-‐wide planning provisions for small wind, in the State Environmental Planning Policy (Infrastructure) 2007, and can be found (and is also included in Section 1.13 below): www.legislation.nsw.gov.au/maintop/view/inforce/epi+641+2007+cd+0+N


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11. Educational Opportunities Alternative Technology Association offers independent guidance and support to members relating to small wind systems and other renewable energy systems. TAFE offers courses in Renewable Energy Technology and workshops on wind system installation and maintenance. Helpful Websites:

• Clean Energy Council (www.cleanenergycouncil.org.au) • Alternative Technology Association (www.ata.org.au) • NSW Renewable Energy Precincts

(http://www.environment.nsw.gov.au/climatechange/renewableprecincts.htm) • American Wind Energy Association (www.awea.org) • Danish Wind Industry Association (www.windpower.org) • Midwest Renewable Energy Association (www.the-‐mrea.org): Hands-‐on workshops

in Wind, PV, Solar Hot water, and more. • RENEW Wisconsin (www.renewwisconsin.org): Fact sheets covering all issues with

small wind (in toolbox mentioned above). • Focus on Energy (www.focusonenergy.org): Great for lots of information on

Renewable Energy. • Home Power Magazine/Website (www.homepower.com): Case studies and stories

of renewable energy installations around the country.


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12. Questions for Potential Installers When selecting turbines and installers, it is important to conduct background research. You will be entering a long-‐term relationship with this manufacturer and installer and should conduct your research upfront with these important questions: 1

• How long has your company been in business?

• How long is the warranty period for the turbine? What does the warranty cover? What is excluded? Is an extended warranty available?

• What rate of warranty work has this turbine required? What problems in the field have been identified? How has the company dealt with them? Who does the work to remedy the problem? Who pays for the work?

• Are there any local installers who can install this?

• How long has this turbine been offered as a production model, available for sale to ordinary consumers, e.g. not in the prototype or beta-‐testing stage? How long was the prototype tested? Who did this testing? How many beta versions were sent to the field for feedback?

• How many production models have been sold to ordinary consumers? How many of the turbines sold are still running?

• What design changes or updates has this turbine seen, and when? If the model has never been updated, why not?

• Does the wind turbine comply with any endorsed international safety and performance standards?

• What is the annual energy output for the turbine in average wind speeds of 4-‐7 m/s? How was this information developed? Has this ever been verified by an independent testing or reviewing agency from real-‐life installations?

• Is there a performance guarantee for turbine output?

• How does one shut down the turbine in the event of high winds, when leaving on vacation for a week or so, or to perform maintenance? Is the shutdown mechanism reliable at any speed? What are the guidelines for shutting down the turbine in high winds?

• What maximum wind speed is the turbine designed for? What about the tower? Has this been certified by a professional engineer?

• Has the turbine ever gone through a reliability test? By whom? What were the results?

• What is the sound profile for the wind turbine at various wind speeds and distances form the tower? Who performed acoustic tests?

1 Sagrillo, M, Woofenden, I. 2009. “How to Buy a Wind Generator.” Home Power.


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13. NSW small wind planning provisions Extract from State Environmental Planning Policy (Infrastructure) 2007

From http://www.legislation.nsw.gov.au/maintop/view/inforce/epi+641+2007+cd+0+N

Current version for 2 March 2011 to date (accessed 31 May 2011 at 10:21)

Part 3 Division 4

Division 4 Electricity generating works or solar energy systems

33 Definitions

In this Division:

electricity generating works has the same meaning as it has in the Standard Instrument.

Note.

The term electricity generating works is defined by the Standard Instrument as follows:

electricity generating works means a building or place used for the purpose of making or generating electricity.

small wind turbine means a wind turbine that has a generating capacity of no more than 100kW.

small wind turbine system means a system comprising one or more small wind turbines each of which feed into the same grid or battery bank.

prescribed residential zone means any of the following land use zones or a land use zone that is equivalent to any of those zones:

a) Zone R1 General Residential, b) Zone R2 Low Density Residential, c) Zone R3 Medium Density Residential, d) Zone R4 High Density Residential, e) Zone R5 Large Lot Residential, f) Zone RU5 Village.

prescribed rural zone means any of the following land use zones or a land use zone that is equivalent to any of those zones:

a) Zone RU1 Primary Production, b) Zone RU2 Rural Landscape, c) Zone RU3 Forestry, d) Zone RU4 Rural Small Holdings.

prescribed rural, industrial or special use zone means any of the following land use zones or a land use zone that is equivalent to any of those zones:

a) RU1 Primary Production, b) RU2 Rural Landscape, c) RU3 Forestry, d) RU4 Rural Small Holdings, e) IN1 General Industrial, f) IN2 Light Industrial, g) IN3 Heavy Industrial,


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h) IN4 Working Waterfront, i) SP1 Special Activities, j) SP2 Infrastructure.

34 Development permitted with consent

1) Development for the purpose of electricity generating works may be carried out by any person with consent on any land in a prescribed rural, industrial or special use zone.

(5) Without limiting subclause (1), development for the purpose of a small wind turbine system may be carried out by any person with consent on any land.

(6) However, subclause (5) only applies in relation to land in a prescribed residential zone if: a) the small wind turbine system has the capacity to generate no more than 10kW, and b) the height of any ground-‐mounted small wind turbine in the system from ground level

(existing) to the topmost point of the wind turbine is no more than 18m.

37 Complying development

(1) Small wind turbine systems Development for the purpose of a small wind turbine system is complying development on any land if:

a) the development complies with clause 20B, and b) the land is not in a heritage conservation area, and c) the system is installed no less than:

i) 25 metres—in the case of a system that has a source sound power level of 0–70 dB(A), or

ii) 40 metres—in the case of a system that has a source sound power level of 71–80 dB(A), or

iii) 126 metres—in the case of a system that has a source sound power level of 81–90 dB(A), or

iv) 200 metres—in the case of a system that has a source sound power level of more than 91 dB(A), or

v) 200 metres—in the case of a system that has an unknown source sound power level,

from any dwelling that is not owned or occupied by the owner of the system, and d) the system is located clear of any works, including power lines, of any relevant network

operator (within the meaning of the Electricity Supply Act 1995) and complies with any requirements of the network operator that relate to clearance from those works, and

e) the system is installed in accordance with the manufacturer’s specifications or by a person who is endorsed for the design and installation of small wind turbine systems under the Clean Energy Council’s wind endorsement scheme, and

f) in the case of any ground-‐mounted small wind turbine in the system—the turbine does not penetrate any obstacle limitation surface shown on any relevant Obstacle Limitation Surface Plan that has been prepared by the operator of an aerodrome or airport operating within 2 kilometres of the proposed development and reported to the Civil Aviation Safety Authority, and

g) in the case of land in a prescribed residential zone: i) the system has the capacity to generate no more than 10kW, and ii) if the system is ground-‐mounted:


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(A) the development will result in no more than one small wind turbine being situated on the lot concerned, and

(B) the small wind turbine has a height of not more than 18m above ground level (existing), and

(C) the small wind turbine is not installed forward of any existing building line on the lot concerned that faces a primary road, and

iii) if the system is not ground-‐mounted: (A) the development will result in no more than 2 small wind turbines being

situated on the lot concerned, and (B) each small wind turbine does not protrude more than 3m above any building to

which it is attached (as measured from the point of attachment), and (C) each small wind turbine is not attached to a wall or roof facing a primary road,

and h) in the case of land in a prescribed rural, industrial or special use zone:

i) the system has the capacity to generate no more than 100kW, and ii) if the system is ground-‐mounted:

(A) the development will result in no more than 3 small wind turbines being situated on the lot concerned, and

(B) each small wind turbine has a height of not more than 35m above ground level (existing), and



which it is attached (as measured from the point of attachment), and i) in the case of land in any land use zone other than a land use zone referred to in

paragraph (g) or (h): i) the system has the capacity to generate no more than 100kW, and ii) if the system is ground-‐mounted:

(A) the development will result in no more than 2 small wind turbines being situated on the lot concerned, and

(B) each small wind turbine has a height of not more than 26m above ground level (existing), and



which it is attached (as measured from the point of attachment).

39 Exempt development

(1) Small wind turbine systems Development for the purpose of a small wind turbine system is exempt development on land in a prescribed rural zone if:

a) it complies with clause 20 (other than clause 20 (2) (f)), and b) the system is ground-‐mounted, and c) each small wind turbine has a height of not more than 35m from ground level (existing),

and


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d) each small wind turbine is installed no less than 200m from any dwelling that is not owned or occupied by the owner of the system, and

e) the development will result in no more than 2 small wind turbines being situated on the lot concerned, and

f) each small wind turbine is located clear of any works, including power lines, of any relevant network operator (within the meaning of the Electricity Supply Act 1995) and complies with any requirements of the network operator that relate to clearance from those works, and

g) each small wind turbine does not penetrate any obstacle limitation surface shown on any relevant Obstacle Limitation Surface Plan that has been prepared by the operator of an aerodrome or airport operating within 2 kilometres of the proposed development and reported to the Civil Aviation Safety Authority, and

h) the system is installed in accordance with the manufacturer’s specifications or by a person who is endorsed for the design and installation of small wind systems under the Clean Energy Council’s wind endorsement scheme, and

i) if the land contains a State or local heritage item or is in a heritage conservation area—the system is not visible from any road at the point where the road adjoins the property boundary concerned.

(1A) Wind monitoring towers The installation of a wind monitoring tower used in connection with investigating or determining the feasibility of a small wind turbine system that has a generating capacity of no more than 1 MW is exempt development on any land if:

a) it complies with clause 20 (other than clause 20 (2) (f)), and b) the tower is located clear of any works, including power lines, of any relevant network

operator (within the meaning of the Electricity Supply Act 1995) and complies with any requirements of the network operator that relate to clearance from those works, and

c) the tower does not penetrate any obstacle limitation surface shown on any relevant Obstacle Limitation Surface Plan that has been prepared by the operator of an aerodrome or airport operating within 2 kilometres of the proposed development and reported to the Civil Aviation Safety Authority, and

d) the tower is installed in accordance with the manufacturer’s specifications or by a person who is endorsed for the design and installation of small wind turbine systems under the Clean Energy Council’s wind endorsement scheme, and

e) if the land contains a State or local heritage item or is in a heritage conservation area—the tower is not visible from any road at the point where the road adjoins the property boundary concerned, and

f) in the case of land in a prescribed residential zone: i) there is no other wind monitoring tower installed on the lot concerned, and ii) the height of the tower from ground level (existing) to the topmost point of the

tower is no more than 18m, and iii) the tower is installed no less than 18m from any dwelling that is not owned or

occupied by the owner of the tower, and g) in the case of land in a prescribed rural, industrial or special use zone:

i) there are no more than 2 other wind monitoring towers installed on the lot concerned, and

ii) the height of the tower from ground level (existing) to the topmost point of the tower is no more than 35m, and

iii) the tower is installed no less than 35m from any dwelling that is not owned or occupied by the owner of the tower, and


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h) in the case of land in any land use zone (other than a land use zone referred to in paragraph (f) or (g)): i) there is no more than one other wind monitoring tower installed on the lot

concerned, and ii) the height of the tower from ground level (existing) to the topmost point of the

tower is no more than 26m, and iii) the tower is installed no less than 26m from any dwelling that is not owned or

occupied by the owner of the tower, and i) the tower is demolished within 30 months after the construction or installation is

completed.

(2) Development for the purpose of a wind monitoring tower used in connection with the investigation or determination of the feasibility of a wind farm that has a generating capacity of more than 1 MW is exempt development if:

a) it complies with clause 20, and b) the tower:

i) is erected in accordance with the manufacturer’s specifications, and ii) has a height of not more than 110m, and iii) is removed within 30 months after its erection is completed, and

c) the site of the tower: i) is enclosed by a fence that prevents unauthorised entry to the site, and ii) is not within 100m of any public road, and iii) is not within 1km of any other wind monitoring tower or a school, and iv) is not within 1km of any dwelling except with the prior written permission of the

owner of the dwelling, and v) is not within 500m of any State heritage item, and vi) does not affect a significant view to or from any such item that is identified in a

conservation management plan (as defined by clause 3 of the Heritage Regulation 2005) for the item, and

d) before the tower is erected, the Civil Aviation Safety Authority (established under the Civil Aviation Act 1988 of the Commonwealth) is notified in writing of: i) the tower’s “as constructed” longitude and latitude co-‐ordinates, and ii) the ground level elevation at the base of the tower, referenced to the Australian

Height Datum, and iii) the height from ground level (existing) to the topmost point of the tower (including

all attachments), and iv) the elevation to the top of the tower (including all attachments), referenced to the

Australian Height Datum, and v) the date on which it is proposed to remove the tower.

Documents

Small%Wind%Site%Assessment%Supplement Abriefexplanation … · 2012. 3. 15. · Developed!as!part!of!the!OEHfunded!Pilot!“Small!wind!siteassessment”Course.! August!2011! Basedonthe!Midwest!Renewable!Energy!AssociationSmall!WindSupplement