Physical Impacts of Grid-Scale Solar Development

Since 2022, Pennsylvania has experienced a significant increase in grid-scale solar development (GSSD), particularly in the southcentral and northwest regions of the state. Much of this activity involves large net-metering and merchant generation projects, typically 3 megawatts (MW) or less.

Over the past decade, solar technology has become substantially more affordable and efficient, making grid-scale solar one of the least expensive and fastest new power-generation options available. As Pennsylvania seeks additional power capacity to meet growing in-state demand and export needs, solar energy is frequently viewed as a "speed-to-power" solution.

Despite this growth, most municipalities in Pennsylvania lack clear zoning regulations for grid-scale solar. Research conducted by Penn State Law indicates that only about 5% of municipal zoning ordinances explicitly allow solar as a principal use, while 87% provide no guidance at all—even for rooftop systems. As more developers approach municipalities with solar proposals, the absence of clear standards can lead to delays, increased costs, and administrative strain.

Establishing clear zoning provisions in advance allows municipalities to manage development more efficiently while placing the responsibility on developers to demonstrate that their projects will not impose undue burdens. This publication outlines the primary physical impacts of GSSD and offers planning strategies to address common concerns.

General Operational Characteristics

Once constructed, grid-scale solar facilities operate quietly and generate minimal traffic. They typically require little water, produce no wastewater, and do not increase school enrollment. Solar development may increase property tax revenue without placing additional demands on public services.

Traffic Impacts

Construction Phase

Construction can generate temporary traffic impacts, including increased truck traffic and on-site workers—sometimes numbering in the hundreds during peak installation phases for larger projects. Construction may last several months to a year and requires advance planning to manage traffic flow and parking.

Planning Recommendations

• Require identification of roads to be used during construction
• Require project construction-phase traffic counts
• Reserve the right to request a traffic impact study
• Require notice of off-site right-of-way or utility work
• Require notification of new or upgraded roads
• Require surety bonding of roads to be used, if impacts are a concern

Operational Phase

Ongoing traffic during operation is minimal and limited to occasional maintenance visits.

Noise

Operating solar facilities typically generate noise that is indistinguishable from background levels beyond the site boundary. The primary sources of sound include inverters, transformers, and tracking motors—generally averaging around 55 decibels. Noise typically fades to ambient levels within 50–150 feet. Proper setbacks can mitigate the potential issue of increased sound from solar development.

Battery energy storage systems (BESS), increasingly co-located with solar arrays, can generate additional noise from cooling equipment and may require expanded setbacks.

Planning Recommendations

• Encourage central placement of inverters and storage equipment, including BESS equipment
• Reserve space for future energy storage additions
• Consider requiring a noise study, with associated costs to be covered by the developer
• Establish protocols for noise measurement and enforcement
• Consider property line boundaries for noise level (dBs) determination

Performance Standards vs. Prescriptive Requirements

Performance standards establish outcomes that developers must achieve while allowing flexibility in how those outcomes are met. In contrast, prescriptive requirements dictate specific solutions and often result in variance requests.

Clear performance-based standards tend to reduce costs, delays, and administrative burdens while allowing developers to design site-specific solutions. These standards should reflect the long-term intentions of the municipality, and the community’s residents, when incorporated into zoning code used for permitting decision-making.

Glare

Solar panels are designed to absorb light, not reflect it, and are generally less reflective than glass. Most glare concerns are effectively addressed through glare studies, which assess potential impacts on roads, residences, and aviation facilities.

Studies typically show minimal glare risk. When issues are identified, adjustments to panel orientation or placement usually resolve them.

Planning Recommendation

• Consider requiring a glare study, and project modifications, if impacts exceed acceptable thresholds.  All costs associated with glare studies should be covered by the solar developer. As glare study results can be complex to evaluate, municipalities will likely need to hire this specific type of engineering skill to review and comment on requested glare study.

Viewshed and Visual Impacts

Visibility of solar facilities is commonly the most significant issue concerning nearby residents when large-scale solar facilities are proposed. Municipalities can require viewshed analyses and visual mitigation measures such as vegetative buffers, berms, fencing, or increased setbacks as a mitigation strategies to reduce these concerns.

Planning Recommendations

• Require a GIS-based viewshed analysis
• Allow zoning officials discretion in determining appropriate buffering/screening

Screening

Screening reduces visual impacts and is commonly required along roads and residential areas. Flexible requirements that allow developers to propose site-appropriate screening plans are often more effective than rigid specifications.

Pollinator-friendly ground cover vegetation is common and encouraged as part of many screening plans.

Planning Recommendations

• Require a comprehensive screening plan tailored to site conditions
• Allow adaptations based on proximity to roads and neighboring land uses

A common screening option used by many municipalities, is a double staggered row of evergreens, 5 to 7 feet high at planting, 15 feet on center, with the expectation of reaching 8 feet tall in three years.  Municipalities might also want to consider a vegetation management plan for any of the trees which die, by requiring the solar developer to replace them within six months, over the life of the project. Deciduous trees can be considered if the intention of the screening to look more like to local background landscape.  If used, deciduous vegetation should be in addition to the main evergreen screening as a supplement.

Fencing

Because solar facilities function as power plants, perimeter fencing is typically required for safety. Fence design should accommodate maintenance access, emergency response, and site-specific needs such as livestock grazing or wildlife movement.

Planning Recommendation

• Require perimeter fencing with adequate setbacks for maintenance and emergency access
• Allow turning radius between interior of the perimeter fence and first row of panels large enough to turn around a large piece of emergency response equipment, such as a firetruck
• Recommended fencing height should be 7 to 8 feet
• Chain-link fence is common but other fencing types can be suitable depending on location
• Consider signage notifying the public of high voltage danger as a reason not to enter the site.  Have signage clearly visible on many perimeter fencing locations
• All gates through fence should be secured with a lock. The primary gate from the road should have a Knox box allowing access through the gate by authorized and trained individuals in an emergency

Setbacks

Setbacks vary widely and may follow underlying zoning standards or establish solar-specific distances from property lines, residences, or roads. Adequate spacing is essential for safety, emergency access, and compatibility with adjacent land uses.

Planning Recommendations

• Require compliance with underlying zoning setbacks
• Consider additional setbacks from residential structures or districts
• Common setbacks for solar in Pennsylvania range from 125 to 225 feet, measured from first row of panels to the property line. Some townships require the setback to be measured from the first row of panels to the first inhabited structure which is not participating in the solar development
• Unique setbacks from historical structures on the National Register or from wetlands are also a consideration

Height Requirements

Ground-mounted solar arrays typically range from 10–20 feet in height. Maximum height standards should reflect topography and community concerns.

Planning Recommendation

• Establish a clear maximum height for ground-mounted panels
• Consider that viewshed is a significant concern of community residents when solar is proposed. Fencing to hide taller panel installations is only a partial solution. Vegetative screening is the most feasible mitigation strategy but is slow to reduce the visual impacts of solar. The taller the panels, the longer until the screening blocks the view. If panels are raised by design to allow for agricultural production (agrivoltaics) underneath them, this is a tradeoff against viewshed issues.

Lot and Parcel Size

Many grid-scale solar projects commonly exceed 100 acres, with larger facilities offering economies of scale for the solar developer. The exception would be large net metering projects, with capacity limitations of 3 MW, which is approximately 15 to 20 acres in size once installed. The larger the project, the greater the land use implications. And the more significant the viewshed impacts. Lastly, large solar projects are predominately being built on open agricultural ground, which along with visual concerns, are top issues of stakeholders in the communities making decisions on siting and permitting.  Dual use of the land, combining solar production with agricultural production is now considered a viable option to reduce the overall impacts to agriculture.

Planning Recommendation

• Ensure lot size and acreage limits comply with the Pennsylvania Municipalities Planning Code
• Consider solar siting in zoning districts near where there is transmission or substation infrastructure in place
• Often on agricultural ground, normally USDA NRCS-designated Class I, II, and III, consider dual use agrivoltaics, as a means to limit the loss of agricultural production.  Many municipalities allow a greater percentage of agland to transition to solar if it retains agricultural production under the panels at the same time.  This could include solar grazing, hay production, various horticultural cropping systems, and others.  In PA, there are numerous municipalities limiting an agricultural parcel to 50% of the land transiting to solar, with exceptions made allowing 75% or greater, if agricultural production will be maintained for the life of the project through the use of agrivoltaics.

Lighting

Solar facilities generally require limited lighting, primarily around transformers. Motion-activated, downward-facing lighting minimizes light pollution and protects dark skies.

Planning Recommendation

• Require dark-sky-compliant, motion-activated lighting
• Request a light at the primary gate for quicker emergency access at night

Fire Safety and First Responder Considerations

Solar panels are largely non-flammable and unlikely to ignite during grass or brush fires. Firefighters require training to safely de-energize systems. National codes and training resources are available to support emergency response. If a solar project is going to proceed in a municipality, after permitting and prior to the start of construction, the solar developer should offer the municipality an emergency response plan uniquely designed for that community.  This should be reviewed and approved by the local, and possibly county, EMS officials. Training should then be coordinated by the developer prior to any site work or construction, particularly if the site will be built in phases. Ongoing training offered as a refresher should be offered every other year, or as determined to be necessary by the EMS officials in coordination with the solar developer. 

If BESS will be built as part of a solar facility, or in proximity, specialized plans and training should be offered as well.  This may also necessitate the need for unique equipment to detect fumes, approach enclosed structures, and suppress fire danger.  Often with BESS equipment, a specialized contractor will be required onsite by the BESS operator to control and contain the emergency.  All BESS facilities should be built to NFPA 855 codes and specifications.

All emergency response planning and training should be initiated and paid for by the solar developer, initially and ongoing.

Conclusion

Clearly defined GSSD standards reduce administrative burdens on municipalities during permitting decisions, and provide site feasibility/predictability for developers. It also allows host community members at large, to offer a clearer voice in how and where, they see energy development, in this case solar, to have a place in their area.

Broad experience, both in PA and nationally, shows that overly prescriptive regulations often lead to increased variance requests and administrative challenges. Performance-based standards which reflect the local community, and meet industry best management practices, are often a viable solution for municipalities to implement. Adopting flexible, performance-based standards, place responsibility on developers to propose effective, site-specific solutions.

For More Information

Comments for Joint Hearing of the Agriculture and Rural Affairs & Local Government Committees on "Utility Scale Solar Development & Local Government Ordinances." Prof. M. Badissy, Penn State Dickinson Law. 2021.

Federal Aviation Administration (FAA) Policy: Review of Solar Energy System Projects on Federally-Obligated Airports. 2021.

National Electrical Code. National Fire Protection Association. 2020.

New York Solar Guidebook for Local Governments. NYSERDA. 2020.

An Overview of Sound from Commercial Photovoltaic Facilities. INTER-NOISE and NOISE-CON Congress and Conference Proceedings, NoiseCon20,  2020.

PA Solar Ordinances: Local Regulation and National Trends. Penn State Solar Law Symposium. 2021.

Top Five Large-Scale Solar Myths. National Renewable Energy Laboratory. 2016.

Utility-Scale Solar Development. Penn State Extension webinar. June 2020.

Utility-Scale Solar and Siting Considerations: Stormwater, Vegetation, Fencing, and Ag Use. Penn State Extension webinar. April 27, 2021.

Notes

"Penn State researchers recently analyzed all the 2,500+ zoning ordinances in Pennsylvania" (in Introduction)

Source: Comments for Joint Hearing of the Agriculture and Rural Affairs & Local Government Committees on "Utility Scale Solar Development & Local Government Ordinances." Prof. M. Badissy, Dickinson Law, Penn State University. 2021.

Inverters are the noisiest equipment. (in Noise)

Source: Top Five Large-Scale Solar Myths. National Renewable Energy Laboratory, 2016.