Darren Lafon-Anthony, Director of Acoustics at Enzygo Ltd looks at noise generated by BESS facilities, the potential impact on the environment and mitigation measures available to reduce noise impacts and target noise levels at receptors.
As the National Grid evolves to meet the changing requirements placed on it, elements such as the introduction of renewables, the rise in electric vehicles and a move away from fossil fuels, have the potential to result in a greater mismatch between energy generation and use than ever before. In this context, Battery Energy Storage Systems (BESS) are more commonly being adopted across the network to regulate the demand on the National Grid.
Depending on the size of the site, a BESS will contain several noise-generating items of equipment, including:
- Battery container;
- Power Conversion System (PCS);
- Localised Transformers; and,
Noise emissions from these items of equipment varies widely depending on size, operating capacity, outdoor temperature, and equipment supplier.
Battery containers generally make little noise during normal operation when external ambient air temperatures are in the 5°C to 25°C range. Outside this range, greater demand is placed on heating/cooling and ventilation equipment to ensure no loss of storage capacity (below 5°C) and no damage due to overheating (above 25°C). It is this heating and ventilation provision that generates noise from battery containers.
Power Conversion System
Usually, the noisiest piece of equipment within a BESS, the PCS is a device for bidirectional conversion of electrical energy between the battery system and the National Grid, i.e., AC to DC and DC to AC conversion. The PCS charges the batteries from the grid during low demand and feeds power from the batteries back to the grid during peak demand. PCS systems are either standalone units or built as a unit containing the PCS and a local transformer.
Typically, quiet in nature, these small transformers tend to emit quite low levels of noise which are generally inaudible beyond the BESS compound.
Depending on the capacity of the BESS, a substation contains a variety of noise generating elements the main one of which will be the transformer with fan assisted cooling with other elements contributing lower noise levels.
NOISE FROM BESS
Given the variability of the noise sources as discussed above, it is difficult to predict their potential impact upon the environment, or develop a suitable mitigation strategy, without comprehensive site-specific data. This includes not only equipment specific noise data and operational modes, but also site layout information including the finished ground levels within the site, the height and elevation of each item of equipment, the height of any plinths the equipment is mounted on and the topography of the surrounding area.
Therefore, it is very important that this information is provided at the outset of the project so that accurate predictions can be made, and appropriate mitigation advised.
POTENTIAL MITIGATION MEASURES AVAILABLE
As with all noise assessments the potential mitigation measures available depend on site-specific circumstances and can include attenuation of the source, acoustic enclosures, acoustic fencing/barriers, earth bunds, etc.
TARGET NOISE LEVELS AT RECEPTORS
Deriving target noise levels at receptors again depends on various factors including specific requirements of the Local Authority, as each authority may have their own take on what they consider is an acceptable level of noise.
Noise from BESS, or any new noise generating development from solar farms (yes, they generate noise too) to energy from waste facilities and/or large-scale industrial developments, should be minimised wherever possible with targets being as close to the pre-development background noise level as possible.
Enzygo provide specialist consultancy services with respect to noise and vibration, providing technical support for residential, industrial and commercial developments energy supply infrastructure (BESS, Solar and EfW) minerals development and waste management sites.