Investigating potential wind farm sites

Author: Craig Memery

Contributor: Alicia Webb

This article describes how you can look more closely at the regions you've identified. The aim is to narrow down your regions of interest into a few discreet sites which look promising. The methods outlined in this article are a guide only, to help you assess sites in a time and cost-efficient way.

Show-stoppers

No wind farm site is perfect. To find the most suitable location, you have to consider several financial, technical, environmental, logistical and social factors. The main priority at this stage is to identify what's known as 'show-stoppers', so you don't waste time investigating unsuitable sites.

There are many barriers to development. A 'show-stopper' could include:

• insufficient wind speed
• lack of suitable electrical grid connection options
• insufficient space for turbines
• unwilling landowners or neighbours, or other objectors
• steep terrain or poor road surfaces, which will restrict access for construction vehicles
• unsuitable geological characteristics, such as underground caves, swampy ground or poor strength soils
• nearby airports or flight paths
• aboriginal cultural heritage or other land restrictions
• endangered or rare flora and/or fauna in the area
• designated 'no go' areas for wind farms
• telecommunication microwave links crossing the site
• buried infrastructure such as fibre-optic cables or water pipelines.

For every wind farm built, dozens of potential sites are assessed but never developed. At any stage during the development period, a site may be deemed unsuitable due to a single significant constraint, so it's best to identify these as soon as possible.

You can rule out some sites simply by researching them. For other sites, you'll need to visit the site to find out more.

For each site, your desktop study should identify:

• likely energy resource – the indicative wind resource in the region
• capacity — potential land area and wind farm size
• non-technical constraints — planning, cultural or environmental issues
• grid connection — availability of nearby electricity network.

Site visits should help you to further confirm:

• the willingness of the landowner to participate in a wind farm project
• site access and construction issues.

Technical constraints

Likely energy resource

It's essential to have a fair idea of the likely wind speed at the site. You can do this by looking at wind maps, or by comparing the elevation and other features of the site in question, with some measured data on nearby sites. Embark can help with this process. Generally speaking, the highest site is the windiest, but of course there are other issues to consider.

The Bureau of Meteorology's wind data

The Bureau of Meteorology has automated weather stations all over the country, which measure temperature, rainfall, wind speed and direction. You can look at a map of all the weather stations on the bureau's website, and buy data for sites you're interested in.

The only problem with this wind data is it’s often measured at only 10 metres above ground level, which means the data is a lot more susceptible to local turbulence than data measured higher up. Also, there are sometimes obstacles near the weather stations.

Bureau data is a great place to start and is useful data and daily or seasonal wind speed variation. But it won't give you an accurate understanding of the wind speed at 70 or 80 metres above ground level, which is what you need to assess the viability of a wind farm.

Capacity

It's up to the community to decide how big it wants its wind farm to be. However, each site you consider will have its own space constraints. It's a good idea at this early stage to calculate how many turbines a site could support. A rule of thumb is that turbines need to be around 500 metres from each other, and at least 150 metres back from any roads, fences, or other infrastructure, and ideally one kilometre from any houses. Drawing an area with these exclusion zones will help you to estimate the installation capacity of the site.

Grid connection

It's important to find out the voltage of the closest electrical grid line, and how far away it is from each site you're considering. Generally, community wind farms of between 2 MW and 10 MW will connect to low voltage distribution lines rather than high voltage transmission lines. Look for lines with a voltage of 22 kV. Unfortunately, the equipment required to connect a small wind farm into a high voltage transmission line is too expensive to make the project financially viable.

The best sites are those closest to the electricity distribution line and not too far from a town, which will use the power generated by the wind farm. The closer the power 'load' (the town) is to the generation source, the less power is lost in moving it around.

The best way to investigate grid access at this early stage is to phone the electrical distribution business that operates in your area.

Site access and construction

You need to investigate whether the sites you've identified are suitable for construction. The two main questions to ask are:

• Will wind farm construction vehicles be able to access and negotiate the site? Particularly steep ridges or hills can make it difficult to transport large turbine components.
• Is the landowner or another local person aware of any restrictive geological characteristics, such as caves, swampy ground, or poor strength soils?

Existing infrastructure

Some infrastructures tend to conflict with wind farm construction. These include:

• telecommunication microwave links
• nearby airports or aerodromes
• buried infrastructure (gas pipes, fibreoptic cables, water pipes)
• forestry (which may adversely affect wind resource).

You can start investigating infrastructure by speaking with local people and the council. It's also a good idea to speak with private infrastructure providers like gas and telecommunications firms.

Noise

At the pre-feasibility stage of a community scale wind farm, noise constraints can be very roughly based on 'setbacks', or distance to residences, to see if the location and size of turbines may be affected.

Setback distance	Recommendation
More than 2.0 km	Noise is highly unlikely to be an issue
1.5-2.0 km	Assume that wind turbine noise requires no further investigation at the pre-feasibility stage
1.0-1.5 km	Consult noise standards for your state alongside information regarding wind turbine sound level specifications for a range of wind turbine models. This may indicate whether turbine sound levels and local planning requirements are likely to impact the wind farm design. If the mean sound intensity is limited to to 35dBA in your area, this requires further investigation and possibly noise modelling.
0.5-1.0 km	Noise is likely to be a design constraint at this site, and it is recommended to bring forward a noise modelling study.
Less than 0.5 km	Noise is highly likely to be a significant constraint for this project. If you wish to consider this site you must bring forward a noise modelling study.

Non-technical constraints

It doesn't matter how many turbines your site can accommodate or how fast the wind is if the site's not right for social or environmental reasons. It's worth looking into these issues too.

Land owners and land use

The landowner's attitude towards wind farms and more specifically the idea of having one on their own land is a high priority consideration. Given that the development is a community project rather than a traditional commercial project, the process of approaching landowners of potential sites will vary widely.

An initial approach in order to gauge the attitude and interest of the landowner is a sensitive issue and should be considered carefully. Local networks are probably the best way to find out who the landowner is and the best way to make contact. Some suggested strategies are:

• Find out if the landowner is a friend or contact of someone in the community group behind the project, and then approach them with the common friend.
• If you can find the landowner's phone number, try calling them to politely inquire about their thoughts on wind farms.
• Use your site visit as an opportunity to find more information such as the street address that may help you find the landowner's phone number.
• Use your site visit as an opportunity to visit the landowner.

If the community group has absolutely no information on the landowner, sometimes title information is available from the relevant planning body in your state or territory. In Victoria, a handy resource is the Vicmap website. Using the ‘interactive map’ and ‘free property report’ functions, you can gather property boundary details at no cost.

Planning

It's a good idea to contact the local council, to gauge their general attitude towards wind farms. They might have local rules or policies that support the development of wind farms.

On the other hand, they might have local planning rules or policies that don't allow wind farms, or they might have refused planning permission for wind farms before. If there are other wind farms in the area, talking to the council could offer a useful insight into how straightforward or difficult the development was.

Environment and cultural heritage

Your maps should show areas of national and state parks, which are generally out of bounds for wind developments. Some maps might also show other information, such as the location of wetlands. Some internet searching may help you locate areas of significant biodiversity, which will limit your ability to develop a wind farm. The Environmental Protection and Biodiversity Conservation (EPBC) website is a good place to do some searches for endangered or protected species in your area.

In addition, you need to know about areas of important cultural heritage near your site. Speaking to the local aboriginal community is invaluable. Your state representative body for aboriginal culture will have a register of important sites. If there are a lot of important sites near your site that could flag a problem.

Look out for:

• state and national parks
• protected coastline
• wetlands
• known habitat for threatened species
• large trees or significant areas of native vegetation
• known cultural heritage sites.

Also ask:

• if there are any local flora and fauna species treasured by the local community, for example wedge-tailed eagles or brolgas
• if any areas within the site are subject to flooding or waterways
• if there are any other significant local environmental characteristics. For example, geological characteristics like caves or volcanoes, or environmental tourism sites
• who the local aboriginal groups are.

Preparing for a site visit

Using either your paper maps, or Google Earth if you are handy with drawing polygons in the program, it's time to map your potential sites in more detail.

Record all potential residences within two kilometres of your site

Until confirmed otherwise, assume that all buildings on your map are residences. It's important to be aware that:

• not all buildings that appear on the maps will be residences — often fewer than half of them will be — and you may not be able to confirm the status of some buildings until you visit the site
• residences may have been built since your map was printed
• usually, small clusters of buildings, and buildings with names, indicate homes
• satellite imaging and aerial photography may help. You can sometimes recognise houses by their driveways, roof types, gardens, and if the maps have sufficient resolution, the presence of 'domestic' outdoor areas.

Run a title search

You can do a title search and purchase title, land owner and address data for a small fee from your state government.

As an example, the Victorian Government land services website has an interactive map which allows you to zoom into your site, measure a distance from the site, and click on properties, adding them to a list. You can then view the addresses for all of these properties.

Other governments have similar services; just search 'land title search' and your state or territory.

Draw setbacks from nearby residences for noise

Wind farm noise continues to be the subject of controversy. However, at the site assessment stage you can treat it the same as any other potential turbine siting constraint.

The most straight forward method is to draw:

• an exclusion zone of a 500-metre radius around all buildings
• a 'danger' zone of 1,000 metres around all buildings.

Don't forget, some of these will not be residences and will not need this exclusion zone.

Draw other setbacks

• Draw a 100-metre exclusion zone around any fences, roads, property boundaries and other visible infrastructure.
• Make sure you go through the list above and rule out any 'show-stoppers' like parkland, wetland, steep cliffs, etc.

Decide where to visit

Hopefully, you'll identify some areas which satisfy all the constraints above and you can go ahead with site visits. Look at road maps to figure out how best to access your areas of interest. Then, get ready to do some walking.

Checklist

• Shortlist potential wind farm sites
• Complete a desktop study for each potential site
• Map each potential wind farm site.