In the third part of our solar and BESS blog series, Acoustic Consultant Mae’r Davis explores the role of acoustic barriers and screening in reducing noise impacts from solar and BESS developments — and how to use them effectively when separation distance and equipment selection aren’t enough.
Where Acoustic Barriers Fit In
The acoustic design hierarchy is a structured approach to minimising noise and managing impacts from noise emitting developments. Metrica works closely with clients to ensure good acoustic design is implemented throughout the development design process. In order of preference the acoustic design hierarchy is as follows:
- Maximising separation distance (see Noise Assessment and Acoustic Design for BESS and Solar Developments #1
- Controlling noise at source (see Noise Assessment and Acoustic Design for BESS and Solar Developments #2)
- Acoustic Barriers and screening
- Operational controls
This blog post focuses on acoustic barriers and screening.
Barriers shouldn’t be your first line of defence for reducing noise impacts — but when distance and equipment orientation can’t fully manage noise risk, barriers can be an effective way of reducing noise impact at receptors.
What Makes an Effective Acoustic Barrier?
Not all fences or walls will work as acoustic barriers. For an acoustic barrier to be effective, it must:
- Be solid and continuous, with no gaps or holes
- Be dense enough to reflect or absorb sound
- Fully break the line-of-sight between the noise source and the receptor
In practice, this usually means timber close-boarded fencing, concrete walls, purpose-built acoustic screening or landscape bunds. The actual materials used to construct an acoustic barrier will depend on the level of reduction required, and local planning implications (i.e. a timber barrier may be preferable to galvanised steel in terms of visual impact etc.). It is also possible to use a combination of barrier types, for example a smaller purpose-built acoustic screen located on top of a landscape bund.
We’ve provided images of typical acoustic barriers below using galvanised steel and timber.
Photo credit: GRAMM Barriers, [https://www.grammbarriers.com/our-products/acoustic-noise-barriers/metasoundblok/]
Where Should I Place My Acoustic Barrier?
The required height and location of any acoustic barrier will depend on the layout of the BESS development and the location of sensitive receptors.
An acoustic barrier should be located close to the noise source to effectively block or deflect sound. Locating a barrier close to the noise source will:
- Maximise the ‘shadow zone’ behind the acoustic barrier
- Sound travels in waves and bends (diffracts) around obstacles
- The closer the acoustic barrier is to the source, the smaller the angle through which sound can diffract over it
- This creates a larger ‘shadow zone’ (i.e. quiet area) on the other side of the acoustic barrier, reducing the amount of noise that reaches sensitive receptors
- Increase the ‘path difference’
- An acoustic barrier works by blocking the direct line of sight between source and receptor
- A longer ‘path difference’ (the extra distance the sound has to travel around the barrier) results in greater attenuation
- Increasing the barrier height increases this path difference
- Reduce the required acoustic barrier height
- An acoustic barrier close to the source can intercept sound before it is more widely radiated, reducing the angle of diffraction
- This means a shorter acoustic barrier can be as effective as a taller one placed further away
- This saves cost, materials and visual impact
- Help manage noise reflections and diffraction
- Placing an acoustic barrier close to the source helps absorb or reflect more of the sound before it spreads widely
- If placed too far away, more sound energy has already radiated in all directions and is harder to control.
Please don’t hesitate to get in to discuss the best location for an acoustic barrier.
An example of moving a barrier closer to the source to increase angle of diffraction and size of the shadow zone is shown below.
What About Landscape Buffers?
Landscaping is often proposed for visual screening — but it’s important to note that trees and shrubs do very little to reduce noise. For meaningful acoustic benefit, you need a physical structure that can block, absorb, or reflect sound energy.
That said, bunds (land mounds) can be effective when designed correctly. A low earth bund with an integrated fence on top can offer dual benefits — reducing noise while blending more naturally into the landscape.
Planning Considerations for Acoustic Barriers
Acoustic barriers can raise questions during planning — especially around visual impact. We can work closely with your landscape architects and planners to balance acoustic performance with design sensitivities. In some cases, we can consider:
- Stepped barrier designs to reduce visual massing
- Bund-and-barrier combinations for rural sites
- Natural-colour finishes or timber cladding to aid integration
Metrica Help Design Acoustic Barriers?
Yes!
We have helped design acoustic barriers on a large number of BESS and Solar developments. Our noise modelling software takes account of local topography, equipment dimensions and equipment location to determine the effectiveness of various acoustic barrier options. Once the noise model is set up, it is easy for us to change the location and height of the barrier to help design the most effective noise barrier for each specific site.
We have helped design acoustic barriers for:
- Cooling fans or HVAC systems on battery containers
- Inverters located close to boundaries
- Transformers or substations with tonal noise emissions
Expert Acoustic Design Advice from Day One
With over 100 successful BESS and solar projects supported to date, Metrica’s team of expert Acoustic Consultants understand how to deploy acoustic barriers effectively — and when to consider alternatives. Whatever stage you are at in the design, we can help you navigate noise risks confidently.
👉 Have questions about barrier design or acoustic screening?
Get in touch with our consultants today for tailored advice.