SOLAR OVERVIEW
Information and answers to frequently asked questions about solar and solar projects.
HOW PHOTOVOLTAIC (PV) SOLAR WORKS
Solar panels comprise many smaller units called photovoltaic cells. These photovoltaic cells are made of glass and a semiconductor material, such as silicon. Photons from sunlight pass through the glass, strike the semiconductor material and knock loose electrons, which then flow through a circuit to create electricity.
BENEFITS OF SOLAR
Solar energy is a clean, renewable power source that helps us reduce our reliance on fossil fuels. As the Illinois electrical grid fills up with more solar from various projects, the demand for fossil fuels will decrease. Furthermore, solar energy projects provide tangible benefits to communities such as local economic growth, electricity savings, and increased energy independence[i].
According to the Illinois Solar Energy Association, a typical solar project will generate 30 years of steady tax revenue to fund schools and other community services while helping keep taxes low for homeowners. In addition to tax revenue, solar projects create local construction and operations job opportunities for local residents and increase business for local services[ii]. Property value studies in Illinois and Indiana have concluded that solar projects do not adversely affect adjacent property values in either the short or long term[iii].
The cost of solar has decreased in the past decade by more than 60 percent[iv], making solar one of the lowest-cost ways to generate electricity. Unlike the fluctuating costs of fossil fuels, solar provides stable, lower-cost electricity[v]. Community solar projects allow residents, businesses, and other entities to subscribe to a local solar array for their power needs in return for solar bill credits, lowering electricity bills.
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[i] Vote Solar. (no date). Why Solar. https://votesolar.org/why-solar/
[ii] Shaver, L. (2019). 4 Ways Local Solar Projects can Benefit Cities. https://www.wri.org/insights/4-ways-local-solar-projects-can-benefit-cities
[iii] SEIA. (2019). Solar and Property Value. https://www.seia.org/research-resources/solar-property-value
[iv] SEIA. (2023). Solar Industry Research Data. https://www.seia.org/solar-industry-research-data
[v] Energy.gov. (n.d.). How Does Solar Work. https://www.energy.gov/eere/solar/how-does-solar-work
SOLAR, HEALTH, AND DURABILITY
According to the Illinois Solar Energy Association[i]:
“Solar panels are safe to touch, attach to your home or install in your neighborhood. Panels are primarily made of glass, aluminum, copper and other common materials. Solar farms also utilize steel racks to position panels, electrical cable and a small number of inverters and electric transformers to deliver power to the grid. All of this equipment is safe and contains the same materials that are found in household appliances. There are trace amounts of chemicals in solar panels that enable them to produce electricity. These compounds are completely sealed within the glass and coatings of the panels. After their useful life, solar panels and equipment are easy to disassemble and recycle. Solar facilities are constantly monitored, and the owners have a business interest in keeping them well-maintained and operating properly. Solar plants are designed to withstand severe weather, and panels are built to last for up to 40 years [of useful life]. If solar panels are damaged, they can be quickly replaced with new ones.“
PV panels are manufactured with ethylene vinyl acetate (EVA) layers, which encapsulate and seal the panels. This allows a panel to remain intact if damaged or cracked – the same way a car windshield remains intact when cracked. The long-term durability and performance demonstrated over decades, as well as the results of accelerated lifetime testing, helped lead to an industry-standard 25-year power production warranty for PV panels[ii].
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[i] ISEA. (n.d.). FAQS – UTILITY, COMMUNITY, AND LARGE-SCALE SOLAR. https://www.illinoissolar.org/FAQ-utility-community-large-scale-solar
[ii] Cleveland, T. (2017). Health and Impacts of Solar Photovoltaics. https://nccleantech.ncsu.edu/wp-content/uploads/2019/10/Health-and-Safety-Impacts-of-Solar-Photovoltaics-PV.pdf
COMPONENTS OF A SOLAR FARM
Primary components of a solar farm include solar panels & racking, inverters, and transformers. Solar panels are mounted on either a fixed-tilt system where the panels are stationary at a set angle or a single-axis tracker system, where the solar panels are placed on a controller that follows the sun throughout the day or. Single-axis tracker systems require additional motors to move the panels.
Inverters convert the direct current electricity (DC) generated by the solar panels into alternating current (AC) used by household appliances. Lastly, transformers are used to boost the voltage for delivery to the electrical grid.
As with other infrastructure development, solar developers cooperate with local fire departments to review project site plans and develop emergency response plans as necessary for the construction, operation, maintenance, and decommissioning of the solar systems. Solar projects are required to be enclosed by a fence with access through a locked gate, and owners will provide gate access (e.g., Knox Boxes) to the local fire department and other emergency service providers.
SOLAR AND FIRE SAFETY
Most components in a solar array are not flammable – the small portion of materials that may be flammable cannot self-support a significant fire. Additionally, there are built-in mitigation protections against extreme weather and fire within the technology itself. For instance, the inverters contain Type I Surge Arresters and are rated as Lightning Protection Level III[i]. The solar array system has built-in wireless communication technology to all the panel rows, meaning that the system can be monitored remotely[ii]. Lastly, PV modules are commonly used on the roofs of people’s homes. Because of this, the UL requires them to comply with combustible materials testing and demonstrate low-flame-spread characteristics.
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[i] SMA. (n.d.). Sunny Central Inverter. https://www.sma.de/en/products/solarinverters/sunny-central-2200-2475
[ii] NexTracker. (2023). NX Horizon. https://www.nextracker.com/nx-horizon-solar-tracker
SOLAR AND INCLEMENT WEATHER
The racking systems that support the panels are built to be configurable up to approximately 140 mph windsx, designed for the American Society of Civil Engineers (ASCE) wind speeds and local code. Tracker panel systems can stow horizontally during inclement weather without needing external power from the grid to move. The panels will be able to achieve these optimal angles even during heavy storms or power outages.
PV systems have been confirmed to withstand hurricanes force winds, such as in Hurricane Sandy in 2012 and during Hurricane Matthew in 2016. During Hurricane Sandy, many large-scale solar facilities in New Jersey and New York suffered only minor damage. During Hurricane Matthew, one leading solar tracker manufacturer reported that their numerous systems in the impacted area received zero damage from wind or flooding[i].
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[i] Cleveland, T. (2017). Health and Impacts of Solar Photovoltaics. https://nccleantech.ncsu.edu/wp-content/uploads/2019/10/Health-and-Safety-Impacts-of-Solar-Photovoltaics-PV.pdf
COMMUNITY SOLAR
Community solar projects allow residents, businesses, and other electricity users to subscribe to a local solar array for their power needs in return for solar bill credits[i]. Rather than traditional solar panel installations on an individual’s or business’s roof, community solar utilizes the energy production from a solar project nearby to power multiple subscribers[ii].
Community solar creates local jobs, generates clean, locally produced energy, and provides savings on subscribers’ electricity bills all without requiring rooftop installation or upfront costs from the subscriber.
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[i] Illinois Shines. (n.d.). Solar Information. https://illinoisshines.com/solar-info/
[ii] Energy.gov. (n.d.). Community Solar Basics. https://www.energy.gov/eere/solar/community-solar-basics
UTILITY-SCALE SOLAR
In Illinois, a utility-scale solar project is generally any solar project with a capacity of over 5 MW[i]. Utility-scale solar projects provide the benefit of fixed-priced electricity during peak demand periods when electricity from fossil fuels is the most expensive[ii]. Utility-scale solar has been generating reliable, clean electricity with a stable fuel price for decades.
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[i] 20 ILCS 3855/1-10
[ii] SEIA. (2023). Utility-Scale Solar. https://www.seia.org/initiatives/utility-scale-solar-power
SOLAR AND NOISE
Solar panels themselves do not produce any noise in operation. During the daytime when the array is generating electricity, the ground-mounted solar inverters and transformers produce a low humming noise. For comparison, this quiet hum is similar to the sound level of a normal, everyday conversation, reaching roughly 60 dB[i]. At 50 to 150 feet from the boundary of the inverter, any sound produced is inaudible[ii].
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[i] CDC. (2022). What Noises Cause Hearing Loss? https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html
[ii] Cleveland, T. (2017). Health and Impacts of Solar Photovoltaics. https://nccleantech.ncsu.edu/wp-content/uploads/2019/10/Health-and-Safety-Impacts-of-Solar-Photovoltaics-PV.pdf
SOLAR IN THE WINTER
Solar systems are designed to handle the weight of Midwest snowfall, being able to withstand .75lbs per square inch[i]. The racking and modules are engineered and selected for the required snow loading according to local code. Additionally, panel modules on a tracking system, move throughout the day with the sun, shedding snow accumulation. Designed for winter, the racking system has a small computer at every row of modules that tracks the sun based on its direction calculated from astronomical tables. It is not necessary for the sun to be shining for the system to track its location in the sky.
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[i] CanadianSolar. (n.d.). Bifacial High Power Dual Cell PERC Module. https://www.csisolar.com/bihiku/
SOLAR AND DRAINAGE
According to the Illinois Solar Education Association, solar farms do not increase runoff and will improve soil and water quality. The land on a solar farm remains vegetated underneath (ie. not paved) so it absorbs rain and helps recharge groundwater. Solar projects are typically accompanied by vegetation plans that identify native, pollinator-friendly grasses that assist in preventing erosion and improving soil quality[i].
Prior to constructing solar projects, owners must prepare stormwater management plans. Professional engineers develop these plans using information from drain tile surveys, topographical maps, and wetlands delineation. Using this process ensures that the final plan for drainage is best suited to the land and ensures that new construction will not contribute to erosion or flooding.
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[i] SEIA. (2019). Solar & Agricultural Land Use. https://www.seia.org/research-resources/solar-agricultural-land-use
SOLAR AND AGRICULTURE
Agricultural land is commonly used for solar projects. However, even as installations continue to expand, solar is not a threat to agricultural activity and does not pose a significant risk to the loss of agricultural land[i].
Solar can provide land with an opportunity to recover – giving soil rest can maintain soil quality[ii] and contribute to the biodiversity of agricultural land[iii]. Additionally, farmers can utilize solar as a steady revenue stream to help smooth out the impact of market volatility[iv].
Land can be reverted back to agricultural uses at the end of the operational life for solar installations[v]. A standard Agricultural Impact Mitigation Agreement (AIMA) is entered into between the owner of a solar project and the Illinois Department of Agriculture typically prior to construction to proactively ensure agricultural land used for a solar farm is restored to its pre-construction condition[vi].
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[i] SEIA. (2019). Solar & Agricultural Use. https://www.seia.org/research-resources/solar-agricultural-land-use
[ii] BRE. (2014). Planning guidance for the development of large scale ground mounted solar PV systems. https://www.bre.co.uk/filelibrary/nsc/Documents%20Library/NSC%20Publications/NSC-publication-planning-guidance.pdf
[iii] BRE. (2014). BRE National Solar Centre Biodiversity Guidance for Solar Developments. https://www.bre.co.uk/filelibrary/nsc/Documents%20Library/NSC%20Publications/National-Solar-Centre—Biodiversity-Guidance-for-Solar-Developments–2014-.pdf
[iv] Energy.gov. (n.d.). Farmers Guide to Going Solar. https://www.energy.gov/eere/solar/farmers-guide-going-solar
[v] Energy.gov. (n.d.). Farmers Guide to Going Solar. https://www.energy.gov/eere/solar/farmers-guide-going-solar
[vi] Illinois Department of Agriculture. (2023). Agricultural Impact Mitigation Agreements. https://www2.illinois.gov/sites/agr/Resources/AIMA/Pages/default.aspx
SOLAR AND WILDLIFE
In the beginning stages of development, a natural resource review consultation with the Illinois Department of Natural Resources (IDNR) is initiated. The IDNR’s Ecological Compliance Assessment Tool (ECOcat) program reviews the solar project’s potential impacts on the environment, such as endangered species habitats and wetlands. A solar project must comply with all applicable requirements resulting from the IDNR consultation to avoid any potential adverse impacts.
According to the Audubon Society, the greatest threat to aviary species is climate change. The Audubon Society supports properly sited renewable energy sites, since “adopting renewable energy is critical to reducing pollution, lowering global temperatures, and preserving the places that birds need to survive”[i].
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[i] Audubon. (n.d.). Solar Power and Birds. https://www.audubon.org/news/solar-power-and-birds
SOLAR AND GLARE
Solar panels are designed to absorb sunlight, rather than reflect it, and most utilize anti-reflective glare front surfaces. These two factors are so effective at reducing glare that many projects throughout the US and the world have been installed near airports with no impact on flight operations. In fact, the United Kingdom and U.S. aircraft accident databases contain no cases of accidents in which glare caused by a solar energy facility was cited as a factor. The Indianapolis International Airport, shown right, has installed solar panels on 183 acres of its property[i].
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[i] IndSolarFarm.com. (n.d.). FAQs. https://indsolarfarm.com/faqs/
SOLAR AND BATTERIES
Some larger-scale grid systems, residential, and other solar power installations include a Battery Energy Storage System (BESS). A BESS is a type of energy storage system that uses batteries to store and distribute energy in the form of electricity[i]. A BESS consists of one or more batteries to store energy for later use and provides benefits of greater efficiency and lower costs overall as compared to other energy storage systems. Most solar projects do not have battery storage.
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[i] Stein, Z. (2022). Battery Energy Storage Systems (BESS). https://www.carboncollective.co/sustainable-investing/battery-energy-storage-systems-bess
