Solar energy is pivotal in the U.S. shift to renewable energy, providing a cleaner alternative to fossil fuels. Photovoltaic (PV) solar panels capture solar energy and convert it into electricity. The popularity of solar PV panels has surged in recent years. According to the U.S. Solar Market Insight 2023 Year in Review by the Solar Energy Industries Association (SEIA), solar accounted for 53% of all new electric generating capacity added to the grid in 2023. By the end of 2023, the U.S. solar industry had added a record-breaking 32.4 gigawatts (GW) of new solar PV capacity, a 37% increase from the previous record set in 2021, and a 51% increase from 2022. The installed capacity of solar PV systems in the U.S. exceeded 100 GW in 2022, with 75% of this capacity deployed within the previous five years. Now, U.S. solar capacity exceeds 200 GW, enough to power 56 million American homes.

In addition to traditional rooftop solar panels and ground-mounted arrays for powering buildings and storing energy, solar panels are used in other important applications. For instance, most of the U.S. Coast Guard’s (USCG) nearly 5,000 lighted buoys are PV solar-powered. The smaller PV panels used by Aids-to-Navigation teams for buoys, lanterns, and other equipment are some of the most commonly generated spent PV waste, which typically contain other hazardous components such as batteries and circuit boards that also need proper management and disposal.

As solar technology adoption accelerates, new challenges arise, particularly in managing the end-of-life phase of PV systems. The current lifespan of a solar PV system is estimated to be about 25-35 years. Despite advancements in technology and materials extending this lifespan, some PV modules are already reaching their end-of-life and entering the waste stream, with many more to follow in the coming decades. PV modules can prematurely reach end-of-life due to weather, physical damage, installation errors, manufacturing defects, and upgrades. By 2030, the cumulative end-of-life PV waste in the U.S. is projected to be between 0.17 and 1 million tons. By 2050, PV system waste could account for upwards of 12% of the annual municipal electronic waste (e-waste) in the U.S. If not managed properly, PV system waste could lead to environmental contamination and waste of valuable resources.

There are many different types of solar panels available, but the three most common types are:

Monocrystalline Solar Panels: Made from crystalline silicon cut from a single rounded ingot, these panels are easily recognizable by their dark appearance and the rounded edges of the individual cells.
Polycrystalline Solar Panels: Made from silicon melted and poured into square molds, these panels typically have a blue, speckled appearance.
Thin-Film Solar Panels: Manufactured by placing several thin layers of PV cells on top of each other to create the module. There are several different types of thin-film solar cells, which differ in the material used for the PV layers, including amorphous silicon, cadmium telluride, and copper indium gallium selenide.

At the end of their life cycles, solar PV systems present significant opportunities and risks. By mass, solar PV modules are made mostly of recyclable materials such as silver, aluminum, copper, glass, and silicon. PV module materials are 99% non-hazardous, and 95% of the materials are recyclable with current technologies. However, challenges in recycling solar PV modules include identifying hazardous materials/parts, recoverability of recyclables, and the cost of recycling. Panels classified as hazardous waste must adhere to strict disposal guidelines, which can include toxicity testing via the Toxicity Characteristic Leaching Procedure or other more stringent state requirements. Currently, the economics of end-of-life handling are unfavorable to recycling, with the cost to waste generators to recycle PV modules around $15-$45 per module, significantly higher than the landfill fee of $1-$5 per module. Therefore, federal and state policy will likely have a large impact on how waste is processed.

Efforts to address solar PV waste are gaining momentum at multiple levels. At the federal level, the Department of Energy Solar Energy Technologies Office (SETO) is working to reduce recycling costs and improve data tracking for solar waste. SETO’s goals include halving recycling costs by 2030 and encouraging the design of panels that are easier to recycle. Programs like the SEIA PV Recycling Partners Program also connect solar owners with certified recyclers across the country. SETO plans to address PV end-of-life issues through their 2022 SETO Photovoltaics End-of-Life Action Plan, stakeholder outreach activities, data gathering, research, and analysis.

In addition to federal actions, some U.S. states, like California, Hawaii, and Washington, have pioneered policies to regulate solar panel disposal. California and Hawaii have adopted federal Resource Conservation and Recovery Act policies, allowing certain panels to be managed as universal waste, streamlining their recycling and disposal. Washington has gone further by requiring manufacturers to provide free recycling for panels sold after 2017.

Managing solar PV waste requires collaboration across the public and private sectors. Recycling, refurbishment, and reuse are key strategies for minimizing environmental impacts. Organizations like the USCG have implemented detailed procedures for managing spent solar panels, emphasizing recycling and safe disposal practices. Key recommendations include:

Recycling whenever possible: Partnering with certified recyclers or refurbishment facilities.
Avoid improper handling: Avoiding crushing or breaking panels, which can release hazardous substances.
Following regulations: Ensuring compliance with state-specific hazardous waste regulations.

As solar installations continue to grow, addressing end-of-life management becomes increasingly urgent. By fostering collaboration between policymakers, manufacturers, and recyclers, the solar industry can transition toward sustainable end-of-life practices. Investments in research, policy harmonization, and public awareness will ensure that solar energy remains a cornerstone of sustainable development without leaving a detrimental environmental legacy.

PHE has been instrumental in helping clients successfully navigate solar PV projects through the current environmental regulatory climate, including the National Environmental Policy Act (NEPA). We ensure that NEPA documents incorporate measures to construct solar PV arrays in the least environmentally harmful ways, while also considering future decommissioning and disposal from the start. PHE's NEPA and environmental compliance experts stay on top of changing requirements, allowing us to efficiently and effectively assist clients in navigating the complex and ever-changing environmental regulatory landscape. We are ready to help clients with any needs related to both environmental clearance and compliance. For any questions or for more information, please reach out to Dawn Schilling, PE, AICP at dawn.schilling@phe.com.

This article was authored by Diego Santaella, an Environmental Scientist at PHE who serves a dual capacity with both NEPA and compliance projects.

News

Solar Energy: A Cornerstone of the U.S. Renewable Transition