Our energy systems are undergoing a major transformation. Electricity demand is rising rapidly, driven in large part by the growth of data centres and pharmaceutical manufacturing. In Ireland, data centres alone accounted for 23% of the country’s total electricity consumption in 2023, up from a mere 5% in 2015 [1].

Projections indicate that by 2030, data centres could represent around 30% of national electricity demand [2]. This accelerating demand places significant pressure on the national grid and our energy infrastructure needs to keep up.

Figure 1: Data centre metered electricity consumption in Ireland from 2015 to 2023 [1].  

Renewable energy is playing an important role towards meeting the increased demand in a sustainable manner. The recently published Climate Action Plan 2025 outlines a commitment to deliver at least 5GW of additional offshore wind, 3GW of additional onshore wind and 3GW of additional solar energy in Ireland by 2030 [3].

Figure 2: Extract from the Ireland’s 2025 Climate Action Plan [3].

These are exciting developments, and it is encouraging to see Ireland’s continued investment in renewable energy. However, large quantities of renewable energy are not without their challenges.  Renewable energy is notoriously intermittent and when the weather changes, the grid needs to be able to react quickly. Hence the need for increased energy storage capacity and fast acting power stations.

Power generation that can ramp up or down quickly in response to changes in electricity supply and demand are commonly referred to as peaking plants. These facilities kick in within minutes of a reduction in supply from solar or wind power generation. This helps maintain stability within the electricity gird and prevents power interruptions.

Ireland already has some very sustainable fast acting power generation and storage facilities. With ESB’s Turlough Hill pumped hydro electric storage system (292MW) in Co Wicklow being the most well-known example of this, alongside our nine hydroelectric power stations, many of which date back to Ireland’s electrification in the early 20th century.

In recent years, we have seen the development of many new gas powered peaking plants and battery energy storage systems (BESS) to assist with the increased demand on the national grid.

Gas powered peaking plants can go from standby to full output in as little as 15 minutes, providing a fast response to grid fluctuations while BESS can instantaneously provide power to the grid. For example, BESS 2 at ESB Aghada in Co Cork which was officially opened in 2024 can provide 150MW of electricity to the national grid for up to two hours [3].  

This is only the beginning; Ireland’s Climate Action Plan [2], outlines a commitment to deliver at least 2GW of new flexible gas generation (gas powered peaking plants) between now and 2030, to support the national electricity grid. The two most common forms of flexible gas generation are:

  • Open cycle gas turbines (OCGT);
  • Reciprocating internal combustion engines (RICE).

As well as the need for fast-acting peaking plants to support the onboarding of additional renewable energy into the national grid, additional base load-generation is also required.

The rapid increase in energy consumption over the last decade has caused such a strain on the energy grid in Ireland that the Commission for Regulation of Utilities (CRU) has brought in new draft guidelines for the development of data centres in Ireland.

These guidelines outline that all new data centres connecting to the Irish electricity network will be required to provide generation and/or storage capacity to match the requested capacity for their facility [2].

Many data centres have already installed their own power generation, and as a result of these new guidelines this trend is due to continue and grow. Onsite power generation at data centres typically consists of a series of modular open cycle gas turbines that are very similar to the peaking plants mentioned above.

What are the acoustic implications of these changes?

The primary acoustic consideration from peaking plants, battery storage and data centres are as follows: 

Peaking plants

Open cycle gas turbines and reciprocating internal combustion engines are largely the same from a noise control standpoint. They contain large gas or diesel powered turbines or engines that turn a series of generators. Most of the noise is generated as breakout noise from the turbines/engines and the generator.

As such, it is essential to enclose these noise sources using an appropriately designed building. These buildings are often made from concrete which is durable and the heavy mass can provide a high level of sound insulation, particularly at low frequencies. However concrete buildings are expensive, and construction time can be long.

Modern methods of construction, such as specially designed acoustic buildings are rapidly replacing concrete buildings. Acoustic buildings are designed using lightweight materials (eg, acoustic sandwich panels) that provide a high level of sound insulation while also being a more cost effective and quicker solution to construct.

Twin skin variations can provide good sound insulation at low frequencies which is often of critical importance when designing noise control solutions for power stations. These buildings can be designed to include a sound absorbing inner face to further help control noise levels, by reducing the build-up of reflective noise within the engine / turbine cell.

Figure 3: Sound Transmission Loss data provided by EnergyLink International from their acoustic building range.

Once the building is in place, acoustic silencers and acoustic louvre systems are required on all inlets and outlets and all doors must be fitted with acoustic seals and automatic closers.

In addition to the building, the fresh air intake and exhaust systems for the engines/turbines need carefully designed silencers. There are also some ancillary equipment that needs to be addressed from a noise standpoint such as external cooling fans, compressors and transformers.

Clever use of noise barriers and enclosures can ensure that noise breakout from these items are appropriately controlled. This results in a low noise development that protects nearby noise sensitive locations and allows power stations to be sustainably built in a variety of urban landscapes.

Data centres

Noise from data centres primarily consists of noise from chillers and cooling equipment and also noise from ancillary power generation. Chillers and related cooling equipment can cause major headaches for data centres especially if it is located close to a noise sensitive location.

The large chillers that data centres use emit noise levels that are in excess of 100dB LwA and these units are typically located on the roof of the building, often with clear line of site to nearby noise sensitive locations.

The two primary noise sources on a chiller are the cooling fans and the compressors. While it is possible to treat each of these individually by enclosing the compressors and installing silencers on top of the cooling fans, the most common way to minimise noise breakout from chillers is good placement away from noise sensitive receptors and by the use of correctly designed sound absorbing noise barriers.

Noise from air handling equipment and ventilation fans for heating, ventilation and air conditioning (HVAC) can typically be controlled using appropriately specified silencers on all fresh and exhaust air ducts. In some cases, it is also required to control breakout from the air handling units and fans by locating them inside an acoustic casing.

Ancillary power generation for data centres tends to come in the form of modular open cycle gas turbines. These modules require the same noise control measures that were described above for peaking plants, albeit on a smaller scale.

Energy storage

ESB has more than 300MW in BESS in Ireland [4]. Battery storage systems are usually fairly quiet. However, they contain cooling fans, inverters and some ancillary equipment and these can create a low-level hum.

Depending on the number of cooling fans, inverters and the proximity to nearby noise sensitive locations there is a small risk of tonal noise transfer. However, this can be easily managed with good site placement and when required, using noise barriers.     

The graph below shows the 1/3rd octave frequency breakdown from a measurement taken inside a large BESS. The graph shows some elevated sound energy at 40Hz, 100Hz and 200Hz, likely due to an electrical hum from the inverters.

Figure 4:1/3rd Octave graph of a measurement taken by Allegro Acoustics in the middle of a large battery energy storage facility during discharge.

Noise limits

The noise sources discussed above can cause significant adverse effects to noise sensitive locations close to these facilities if not appropriately addressed through effective noise control.

High noise levels can result in sleep disturbance, annoyance and increased the risk cardiovascular disease, diabetes and stress [4]. Thankfully, noise emissions from these sites are regulated to protect nearby noise sensitive locations. New power stations and data centres in Ireland require an industrial emissions licence (IEL) and this licence includes noise the following noise limits that the facility must adhere to: 

  • Daytime (07:00–19:00): 55dB LAeq.
  • Evening (19:00–23:00): 50dB LAeq.
  • Night-time (23:00–07:00): 45dB LAeq

A +5 dB penalty is applied to the specific noise level from the facility if any tonal or impulsive characteristics are present during daytime or evening hours. At night-time, tonal or impulsive noise is not permitted. These limits apply at the nearest noise sensitive locations to the facility and are strictly monitored via an annual noise monitoring survey carried by a suitably qualified noise control engineer.

A noise sensitive location is defined as 'Any dwelling house, hotel or hostel, health building, educational establishment, place of worship or entertainment, or any other facility or other area of high amenity which for its proper enjoyment requires the absence of noise at nuisance levels'.

Figure 5: An engineer from Allegro Acoustics carrying out an annual noise monitoring survey for a CCGT power station.

The best way to meet these noise limits is to design the facility with acoustics and noise control in mind. Of course, it is also possible to retrofit noise control solutions, but this tends to be more expensive and has the potential to disrupt operations.

In order to design an energy or data centre project with noise control in mind, it is essential to employ the services of a competent noise control engineering team from the onset. A good noise control engineer will carry out the following assessment:

  • Review the proposed facility relative to the nearby noise sensitive locations.
  • Measure and record the existing baseline noise level.
  • Propose suitable noise criteria, typically based on the limits and guidance set out in Guidance Note for Noise (NG4) [6] and BS 4142 [7].  
  • Develop a 3D environmental noise model of the facility using SoundPLAN or a similar noise modelling software.
  • Apply the model to identify potential noise impacts and specify the appropriate noise control measures to be incorporated into the facility’s design.
  • Verify compliance by repeating the noise survey once the facility is operational, ensuring that project noise limits have been achieved.

This process ensures that the facility operates quietly and unobtrusively, supporting a stable electricity grid and continued energy development that responds to a changing landscape without causing noise nuisance. 

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Author: Stephen Kearney holds an honours degree in energy systems engineering from the University of Galway and a postgraduate diploma in acoustics and noise control from the Institute of Acoustics (IOA). He has spent more than a decade providing noise control engineering solutions to power stations, data centres and renewable energy installations throughout Ireland and the UK. He is the technical director at Allegro Acoustics and is leading the company towards becoming Europe’s No 1 provider for industrial noise control services. 

References

  1. Central Statistics Office, 'Data Centres Metered Electricity Consumption 2023', July 23, 2024. [Online]. Available: https://www.cso.ie/en/releasesandpublications/ep/p-dcmec/datacentresmeteredelectricityconsumption2023/.
  2. Government of Ireland, Climate Action Plan 2025.
  3. Electricity Supply Board, 'ESB officially opens its latest battery storage project in Co Cork as part of €300m investment' ,2024. [Online]. Available: https://esb.ie/media-centre-news/press-releases/article/2024/11/15/esb-officially-opens-its-latest-battery-storage-project-in-co-cork-as-part-of--300m-investment.
  4. Commission for Regulation of Utilities, Large Energy Users Connection Policy Proposed Decision Paper CRU/202504, February 18, 2025. [
  5. Electricity Supply Board, 'Battery Storage', Electricity Supply Board, 2025. [Online]. Available: https://esb.ie/what-we-do/generation-and-trading/battery-storage.
  6. World Health Organization , Environmental Noise Guidelines for the European Region, 2018.
  7. Environmenatal Protection Agency, Guidance Note for Noise (NG4), 2016.
  8. British Standards Institution , BS 4142 Methods for rating and assessing industrial and commercial sound, 2014+A1:2019.
  9. Sustainable Energy Authority of Ireland, National Energy Balance for 2023.