Solar and Battery Storage Noise Mitigation Best Management Practices

Although these types of developments are generally not major noise concerns, steps can be taken to address concerns that adjacent property owners might have.

Regulatory Framework

In Pennsylvania, noise is addressed by municipalities or counties, usually in zoning ordinances. Most ordinances set a flat rate of around 45 to 60 decibels (A) measured at the property line. Other zoning ordinances may simply require that the developments meet the noise limits of the underlying zoning district. If the system is causing issues for neighbors, they have the right to report it to the zoning officer, who can then measure noise levels to determine whether the array is in compliance. Generally, decibels for this type of development are measured in A-weighted decibels (dBA), the standard set by the American National Standards Institute (ANSI). This measurement is useful because it prioritizes frequencies to which human hearing is most sensitive. (Sygrove 2024)

Balancing priorities

While many are familiar with large-scale solar development, an emerging trend is Battery energy storage (BESS) development. BESS are systems designed to absorb electricity from a nearby solar or wind site or from the grid, store it, and then use it at times when the grid needs more electricity. With a significant portion of the sound coming from active cooling to maintain safe operation of a BESS, it creates a tradeoff. While steps can be taken to reduce the noise of cooling systems, care must be taken to ensure these measures don't compromise their primary function. This trade-off will also be discussed further, including how fire and electrical code regulations might affect other mitigation measures aimed at reducing the noise impacts of BESS.

Noise-producing equipment on-site

Electrical equipment

Every Solar and BESS has basic electrical equipment that will produce a hum when operating. This comes in the form of inverters and transformers, as well as a dedicated substation used in large-scale systems.

Cooling equipment

Maintaining an appropriate operating temperature for BESS is essential for efficient and, more importantly, safe operation. Cooling fans, while performing this crucial role, can contribute significantly to a site's noise profile during operation. It should be noted that cooling requirements can vary with battery usage, increasing during charging or discharging. The environment can also play a role, with hotter, sunnier days often requiring more effort from cooling fans to maintain proper operating temperatures. (Eriksson, 2023)

Emergency alarms

While other BESS components produce fairly steady background noise, alarms are reserved strictly for emergencies. These will only alert if there is a significant issue with the battery or during required testing by fire codes. Testing times should be planned so as to not create any unnecessary nuisance during nighttime hours.

Overall noise

Solar arrays are generally quiet, aside from the electrical equipment and potential substation. With proper siting, most arrays will usually blend into the background noise at distances of 50 to 150 feet. (Murphy, 2021)

For BESS, noise impacts can vary with project size and the locations of different components, but the cooling fans that come with BESS will generally make the overall noise impact louder than that of a standalone solar system. The Pacific Northwest National Laboratory found, in a few case studies using setbacks of about 400 ft at a specific site, that noise at the property line was reduced from 101 dB(A) to 59 dB (A), the equivalent of a conversation. Another case study with a 125-foot setback, an 8-foot perimeter fence, and natural screening, including trees, reduced its noise level to 55 decibels at the property line. (Twitchell, Powell & Paiss, 2023)

Mitigation Practices

Placement

Usually, the best mitigation strategy for reducing noise impacts is distance. With central inverters and transformers, developers can place them at the center of the array or at a distance that is feasible from sensitive receptors such as residential properties, parks, or historical sites. Sound can also be dissipated by natural barriers, such as trees and hills. Potential natural barriers should be included in any decisions about where to place electrical equipment such as inverters, transformers, or a substation. For standalone BESS, this may be harder to accomplish with the more limited space they have to work with compared to a solar array or a solar + storage system. In cases with more limited space, other measures may be needed. (Eriksson, 2023)

Sound-dampening measures

When physical setback distance alone is insufficient, developers can mitigate BESS noise by addressing the cooling systems. Solutions include installing sound-dampening equipment around cooling units and using variable-speed fans. Variable-speed fans automatically adjust to thermal demand, operating much more quietly when the battery is idle or during cooler nighttime hours. (Eriksson, 2023)

Another option is to create physical barriers around the noise for outdoor systems, which is preferred for system safety. This may take the form of walls or chain-link fences fitted with vinyl to serve as barriers. Generally, barriers are most effective when they are higher than the noise- producing elements they are trying to block. (Storm & Leech, 2022) When trying to block sensitive receptors, breaking the line of sight between an on-site noise emitter and the sensitive receptor is more effective at blocking the generated noise. For battery storage, the now-standard container unit is about 8 feet tall. Also, the general practice is to simply put up a barrier around the site's perimeter. While this works, a more effective barrier strategy is to place barriers between systems and along the perimeter. This does come with considerations about how it may affect compliance with fire codes, which may require certain clearances between structures and potentially require a site to expand its land use and wiring to accommodate. While in most cases a perimeter barrier can be effective with proper height and soundproofing coating, individual barriers may be considered if a system can't avoid being too close to sensitive receptors. (Eriksson, 2023)

Considerations for Zoning Ordinances

First, consider the zoning district the project will be in. It may make more sense to align noise requirements with those applied to all other uses in the zoning district. A municipality could also set specific sound standards for each or select groups of zoning districts based on the types of uses they may host.

Ordinances may also want to set standards for how sound is measured to help legitimize any measurements taken that show a violation. Standards might require that a decibel meter meet or exceed ANSI SI.4-2014 standards. (Ordinance 2026-04: Amending the SALDO regarding BESS , 2026)

Township may also consider measuring the 1-hour Equivalent Continuous Sound Level (Leq), which averages the noise level over an hour, providing a better indication of the facility's actual continuous noise. (NC Clean Energy Technology Center, 2026)

For standalone solar arrays, general standards should be sufficient to mitigate potential noise impacts. For BESS with larger sound profiles, municipalities may consider requiring a sound study conducted by a professional acoustical engineer to demonstrate that the site will not produce sound exceeding a given level.

Noise can be a difficult topic to address, but proper standards can help energy developers meet reasonable expectations without burdening residents.

Sources

Sygrove, C. (2024). Decibel chart: Common sound levels. 

Eriksson, L. (2023). Battery energy storage systems - Their environmental noise emissions and possible mitigation pathways. Proceedings of Meetings on Acoustics, 52(1), Article 040014. doi.org/10.1121/2.0001951

Murphy, T. (2021). Municipal Officials' Guide to Grid-Scale Solar Development in Pennsylvania. Penn State Extension.

Twitchell, J. B., Powell, D. W., & Paiss, M. D. (2023). Energy storage in local zoning ordinances (Report No. PNNL-34462). Pacific Northwest National Laboratory. 

Storm, M., &Leech, J. (2022). Battery energy storage system facility implementation, noise control, and sound abatement considerations. INTER-NOISE and NOISE-CON Congress and Conference Proceedings, 264(1),764-774. 

Ordinance 2026-04: Amending the Subdivision and Land Development Ordinance (SALDO) regarding battery energy storage systems (BESS). (2026).

NC Clean Energy Technology Center. (2026). NC utility-scale solar and storage model ordinance (Version 1). Carolinas Development Assistance and Siting Hub.