Lentis/Solar Panel Recycling in the United States

Introduction
Over the last several decades, solar photovoltaic modules have grown in popularity as a choice for clean energy generation. Increased use has led to the challenge of dealing with the large volume of waste produced by end-of-life (EOL) solar panels; the cumulative mass of EOL panels is projected to reach 80 million tons by 2050. A sustainable solution to this problem is required for solar panels to maintain their reputation as a clean energy source, one of the technology's main appeal. With no current federal regulations mandating a sustainable solution in the U.S., state legislations have begun to approach the challenge with diverse strategies.

This chapter describes current and proposed solutions to solar panel recycling in the United States.

Technical Obstacles
Solar panel photovoltaics require different processing depending on panel composition and manufacturing procedures. Two main processes exist for the different types of solar technology: crystalline silicon (c-Si) and thin-film panels. For c-Si panels, the aluminum and glass is first disassembled with 95-100% recovery. Thermal processing, physical separation and chemical etching is used to separate modules and silicon with 80-95% recovery. This process occurs at high temperatures requiring high energy inputs. Thin-film panels are shredded, physically separated with vibration and rinsing, and chemically separated using strong acids. This is also an energy intensive process that results in 90-95% recovery of glass and semiconductor material.

The biggest technical challenges with recycling photovoltaic cells are high energy input, use and disposal of harmful chemicals, and lack of homogeneity in panel composition and construction. As more research is being done in photovoltaics, panel composition could change, making established recycling facilities obsolete. Panel construction can change to be more recyclable, but current technology requires recycling infrastructure that can handle difficult disassembly.

Economic Obstacles
Solar panel recycling is not currently economically favorable. The National Renewable Energy Laboratory reports that the cost to recycle one photovoltaic module ranges from 15 to 45 USD, whereas disposal in a non-hazardous or hazardous landfill can cost less than 1 or 5 USD, respectively. Solar panel waste contains many valuable components that could make recycling economically viable, but there are no current methods to extract them cheaply and on a large scale. Such an economic obstacle requires technical advancement over the long term and policy changes for immediate effect.

Washington
In 2017, Washington State legislature passed a renewable energy bill that included the Photovoltaic Module Stewardship and Takeback Program. The bill mandates the establishment of a "convenient, safe, and environmentally sound system," financed by the manufacturers, to recycle all solar panels sold in the state after July 1, 2017. Washington is the first state to implement a takeback program.

The takeback program hopes to implement solar panel recycling as the norm for EOL modules by asserting that the modules are destined for recycling. The program also protects the consumer incentive for solar panels by placing the financial responsibility on the manufacturer. This strategy makes solar panel recycling easy and accessible for owners, but it could discourage solar panel sales in Washington since it is the only U.S. state to have these restrictions.

California
California classified solar panels as universal waste in 2020. Universal waste includes products containing non negligible amounts of hazardous materials like pesticides or batteries. Universal waste is more regulated than e-waste, the label for most household electronics despite generally containing more hazardous material. Regulations for universal waste make it difficult to implement recycling processes as they are not allowed to use water, chemicals or heat.

Alternatives to recycling include disposal in a landfill or transportation to another state. To be disposed in landfills, the panels must be verified to contain no hazardous materials using the record of manufacturing materials or a laboratory test costing the consumer around $1,500. Exporting panels to states with less regulation dissuades consumers from coordinating end-of-life procedures since it cannot be done locally.

California is making progress by passing legislation targeting panel classification, but the decision for universal waste is criticized as it discourages consumers from electing sustainable options such as recycling due to complicating processing options.

Rhode Island
Rhode Island proposed a bill, H5524, in February, 2021 requiring solar panel manufactures to recycle their equipment at end-of-life. This bill was supported by environmentalist groups and based on legislation for hard-to-dispose-of-products like mattresses, paint cans and light bulbs. The bill was openly opposed by local solar groups like Green Development LLC and Northeast Clean Energy Council. They stated it would discourage photovoltaic manufactures from participating in the RI market unless neighboring states passed similar legislation, which would create economic hardship for established RI-based companies. The bill failed in June, 2021 after a study by the House Environment and Natural Resources Committee suggested vetting solar panel recycling before making new proposals.

North Carolina & New Jersey
North Carolina House Bill 479 tasks the North Carolina Environmental Review Commission to investigate matters related to the decommissioning of utility-scale solar projects, which are defined to be ground-mounted solar power projects directly connected to the electrical transmission grid for sale. This includes many types of solar panels, solar arrays, buildings, facilities, and any other infrastructure involved in the project. The Environmental Review Commission reported the findings and recommendations of the study to the General Assembly, and the data will be taken into account for any future laws or regulations regarding solar panel end-of-life management within the state.

Similarly, the New Jersey Legislative also created a bill calling for the creation of a solar panel recycling commission to investigate options for recycling and other end-of-life management for solar panels and solar energy generation structures. Although these investigations provide useful estimates for things like the necessary infrastructure to support recycling, which can inform future programs, they do not mandate any new regulations which makes their impact unclear.

Hawaii
In the 1990s, the federal government became more involved in the research and development of solar energy. Grants and tax incentives were given out to homeowners to encourage the installation and use of solar systems. Solar panels installed in the 1990s are nearing the end of their thirty years life span and will start requiring disposal. In 2008, the legislature passed Act 204, Session Laws of Hawaii, commonly referred to as the "solar water heater mandate", that requires new homes to utilize solar water heating.

A bill was proposed to require the Hawaii State Energy Office and the Department of Health to conduct a comprehensive study, to determine the best practices for the disposal and recycling of solar panels and other appliances dependent on solar energy. The study will address (1) the number of aging solar panels in Hawaii that will need to be disposed of or recycled, (2) the type and chemical composition of those solar panels, (3) the best practices for the collection, disposal, and recycling of photovoltaic waste for adoption across local, national, and international communities, (4) whether a fee should be charged for the disposal or recycling of solar panels, and (5) any other issues that the state office of energy and the department of health consider appropriate for photovoltaic waste disposal and recycling.

The bill passed in the House of Representatives in February, 2022 and has been transmitted to the Senate where it is currently awaiting approval before being introduced to the governor.

Solar Energy Industries Association
The Solar Energy Industries Association (SEIA) is the national non-profit trade association of the solar-energy industry in the United States. SEIA has taken the lead for the responsible disposal of solar panels by establishing takeback and recycling programs nationally. SEIA works with regulators to develop implementable legislation and manageable processes for compliance. SEIA's PV Recycling Working Group partners with major solar manufacturers and installer-developers such as First Solar, SunPower, Flex, JinkoSolar, Panasonic, SolarCity, and Trina Solar in order to establish a network of cost-effective recyclers that can responsibly manage PV waste and end-of-life disposal of PV panels.

Tom Kimbis, SEIA's interim president, claimed that he wants "to make the entire solar industry landfill-free by establishing a national network of collection points, recycling facilities and an easy-to-use consumer web portal, this proactive program will help drive down the cost of recycling for all parties involved. This means the environment wins and so do our solar consumers and companies."

SEIA's photovoltaic recycling program consists of three major steps. First, the SEIA member gathers information on the equipment that will be recycled. Then, the SEIA member choose a recycling partner from the many companies that SEIA can connect them with. Finally, they prepare documentation and arrange for the collection, transportation, and drop-off of the equipment to the recycling partner. Finally, the equipment is recycled according to the chosen recycling partner's policies.

Conclusions
Solar panel recycling is a social, technical and economic issue. The United States' decision to allow states to elect their own EOL legislature for photovoltaics has resulted in varied progress across the country. The SEIA and takeback programs by local solar companies have started to manage the growing volume of retiring panels despite the lack of direction from legislature. For lasting and equivalent options to be available to PV consumers across the U.S., more funding for standardized takeback programs and research into recycling processes must be demanded by consumers to their state governments. The future of solar panel recycling can help maintain solar energy's green characteristics, but progress must be made in all aspects of EOL programs and processing.