In the second instalment of our solar and BESS blog series, Senior Acoustic Consultant Emily Tilbury explains how equipment selection, orientation and use of acoustic attenuators can significantly reduce noise impacts on nearby receptors.
Good Acoustic Design Starts Early
In our first post, we explained how siting noisy equipment away from noise-sensitive receptors is the foundation of effective acoustic design. That principle sits at the top of the acoustic design hierarchy we apply to every project:
Acoustic Design Hierarchy
- Maximise the separation distance between noise sources and receptors (see Blog post 1: Noise Assessment and Acoustic Design for BESS and Solar Developments)
- Noise control at source
- Acoustic barriers and screening
- Operational controls
By applying the principals of this hierarchy, Metrica will help reduce planning risks, avoid redesigns, and help ensure your site gets planning consent.
This blog focuses on noise control at source — including:
- Selecting quieter plant and equipment
- Strategic equipment orientation
- Use of acoustic silencers, enclosures, and attenuators
Selecting Low-Noise Equipment
Before thinking about barriers or layout, let’s start with the equipment itself. Since noise impact is a key planning requirement for solar and BESS developments, careful consideration of the batteries and inverters noise emissions during the initial design is essential.
There is an increasingly wide variety of battery and inverter manufacturers available as more suppliers come to market, with each system emitting different noise levels. For example, liquid-cooled systems generally operate more quietly than traditional air-cooled units. Both rely on fans — but fan noise can vary significantly by manufacturer and fan duty cycle.
We understand that at the early stages of the design, the batteries and inverters which will be ultimately installed in practice may not be known. In this instance, we would often undertake noise modelling of the clients preferred supplier, as well as an alternative option. The benefit of this approach is it allows for a comparative assessment of potential noise impacts, ensuring that the site design remains robust and compliant with noise limits regardless of the final equipment selection.
Most product datasheets provide sound levels based on 100% fan speed, often tested in warmer climates. That means real-world noise emissions in the UK are often lower, with fans having to work less hard to maintain suitable operating temperatures. As such, it’s worth confirming with the manufacturer what the typical operational fan speeds will be at your site. Having this data available during early-stage noise modelling can streamline the process and demonstrate that your preferred supplier will be acceptable in terms of noise.
At Metrica, we’ve built extensive knowledge of available battery and inverter systems, as well as and their acoustic profiles. If you’re unsure where to start, we can provide guidance on equipment selection to reduce noise risk from day one.
Orientation Matters
Once you’ve selected your equipment and maximised separation distances, it’s time to think about orientation.
Both battery containers and inverter units will typically emit some noise from all sides. However, sides with cooling fans typically emit more noise than sides without, due to the mechanical operation of the fans and the movement of air through ventilation grilles or louvres, which can create broadband and tonal noise components. Wherever possible, orient the noisiest side away from nearby receptors.
It is important to note that although string inverters are quieter individually, their cumulative impact across a large site can still be significant and should be modelled to ensure adverse impacts are avoided.
Attenuators, Silencers, and Enclosures
Another way to control noise at source is through attenuators, silencers and enclosures.
Acoustic attenuators and silencers can be added to air intake or outlet vents to reduce noise. However, these need to be carefully designed such that they avoid reducing airflow.
There is no one-size-fits-all solution. Some manufacturers offer bespoke attenuation packages, while others use “off the shelf” components. That makes acoustic compatibility an important factor in equipment selection.
Acoustic enclosures offer another effective solution. These structures encase noise-generating equipment to create a layer of sound insulation between the unit and its surroundings. A well-designed enclosure balances noise attenuation with proper ventilation, often using acoustic louvres to maintain airflow while minimising emissions.
It is always worth asking equipment suppliers if they offer acoustic attenuators or enclosures early in the process to identify potential mitigation options, manage noise risks proactively, and avoid costly retrofits or design changes later in the project.
Design It Right from the Start
By embedding good acoustic design into your layout and procurement processes, you not only reduce planning risk but also demonstrate environmental responsibility to local stakeholders. Incorporating these acoustic design principles early can help you:
- Simplify the planning and approval process
- Avoid costly redesigns
- Reduce the risk of long-term operational noise complaints
At Metrica, we’ve delivered over 100 successful noise assessments for solar and BESS projects, partnering with some of the UK’s biggest names in power generation. Whether you need early-stage noise modelling or final noise impact assessments for planning, we’re here to guide you through every stage.
Let’s Talk Noise Risk
Planning a solar or BESS development?
Talk to one of our experienced acoustic consultants today for practical advice specific to your project. We’ll help you identify and mitigate noise risks — before they become planning delays.
👉 Get in touch with our team today.
