Fukushima Turns Solar Panel Glass Into Insulation as Japan Prepares for a Wave of Waste

From Retired Solar Panels to Home Insulation

Three companies in Fukushima Prefecture are turning glass from discarded solar panels into insulation for homes, testing a way to handle a waste problem that Japan expects to grow to between 500,000 and 800,000 tons a year by the late 2030s.

Takaryo Corp., Toshima Glass and Paramount Glass Mfg. Co. are crushing protective panel glass, mixing it with other discarded glass and melting it into material that can be spun into insulating fibers. Their tests have shown that adding one ton of solar panel glass to 100 tons of insulation does not compromise the finished product's quality.

The gap between a successful test and a commercially viable operation remains large. The companies currently use one ton of panel glass a month in test production. Paramount Glass estimates that commercial production would require at least 100 tons a month, or 100 times the current amount.

Fukushima's prefectural government has begun subsidizing transport costs to support the work. Heavy glass is expensive to move from solar power plants to recycling facilities, while the recovered material itself sells for very little.

As of June 17, 2025, the initiative sits alongside a wider Japanese effort to develop recycling equipment, find buyers for recovered materials and prepare mandatory recycling rules. Fukushima, which expanded renewable energy after the 2011 nuclear disaster and has Japan's highest annual solar power generation output, is confronting what happens when those installations eventually wear out.

The immediate task is practical: turn a large, difficult waste stream into something manufacturers can use, at a cost that allows recycling to compete with disposal.

Why Japan Faces a Surge in Discarded Panels

Japan's solar expansion accelerated after the 2011 Fukushima nuclear disaster. In 2012, the government introduced a feed-in tariff, or FIT, which guaranteed fixed prices for renewable electricity. That assurance helped encourage a nationwide wave of solar installations.

By 2022, Japan's installed solar capacity had reached 85 million kilowatts, making it the world's third largest. Installed capacity describes how much electricity the equipment can produce at a given moment, rather than the total electricity it generates over a year.

Solar panels typically last 20 to 30 years. The large number installed in the early 2010s is now moving toward the period when replacement and disposal will become increasingly common. Hundreds of thousands of tons of annual waste are expected from the mid-2030s, with the Environment Ministry estimating between 500,000 and 800,000 tons annually from the late 2030s.

The sequence shows why the recycling industry needs to prepare before the largest volumes arrive:

• 2011: The Fukushima nuclear disaster was followed by a major push to expand renewable energy.
• 2012: Japan introduced guaranteed fixed prices for renewable electricity through its FIT system.
• 2022: Installed solar capacity reached 85 million kilowatts, the third largest total worldwide.
• Mid-2030s: Annual discarded panel volumes are expected to reach hundreds of thousands of tons.
• Late 2030s: The Environment Ministry estimates annual disposal needs of between 500,000 and 800,000 tons.

Why Landfill Disposal Creates Problems

Most discarded solar panels currently go to landfills. The expected increase in waste could overwhelm existing industrial waste facilities and landfill sites, making continued reliance on burial difficult to sustain.

Panel waste also requires careful handling because panels can contain hazardous substances, including lead and, in some cases, cadmium. If these materials are not properly managed, they can leach into soil and water. Recycling is therefore about managing potentially harmful components as well as recovering usable glass and metals.

Japan's limited landfill space adds urgency. Every quantity of glass recovered for manufacturing is material that no longer needs to occupy a disposal site. The challenge is to build enough processing capacity and reliable demand for the recovered material before waste volumes rise sharply.

What Makes Panel Glass Difficult to Recover?

A solar panel is a tightly bonded stack of materials. Its surface facing the sun is made from tempered glass of high purity. Below that are ethylene-vinyl acetate resin, commonly called EVA, photovoltaic cells that are usually made from silicon, another EVA layer and a backing sheet.

The photovoltaic cells convert sunlight into electricity. The surrounding resin holds the layers together, but that strong bond makes dismantling the panel difficult. Recovering the glass means separating it from resin, cells and embedded metals.

Specialized equipment and processes are needed for that separation. A recycler must produce materials suitable for another use while also handling the remaining panel components responsibly. The cost and complexity of doing so help explain why finding a useful destination for the glass is only one part of the job.

Solar panel glass also contains different substances from ordinary bottle glass. Manufacturers using both must adjust their mixtures, a process that takes time and adds expense. A furnace needs a suitable blend if it is to produce insulation of consistent quality.

How Fukushima Makes Insulation From Glass

Takaryo, Toshima Glass and Paramount Glass have joined forces around a manufacturing route that combines recovered panel glass with other waste glass, including bottles. Their process turns the mixed material into fibers used to insulate homes.

The production steps are straightforward to describe, even though controlling the mixture is technically demanding:

• Crush the protective glass from used solar panels into small pieces.
• Mix those pieces with other discarded glass, including bottle glass.
• Melt the mixture in a furnace.
• Spin the molten glass into fibers for home insulation.

The tests involving one ton of solar panel glass in 100 tons of insulation show that the recovered glass can enter this production process without reducing the final product's quality. The approach gives the construction industry a usable material while diverting glass from landfill.

For Fukushima, that connection between recycling and manufacturing is central to the project. Collecting glass addresses disposal, while turning it into insulation creates a product that can be sold and used in buildings.

The Commercial Gap Is Still Large

Paramount Glass's estimate of at least 100 tons of protective glass a month for commercial production sets a demanding scale target. At the current test rate of one ton a month, the partners are using just one hundredth of that amount.

Recycling also costs more than simply disposing of the glass. Time spent adjusting the mixture, specialized separation processes and transport charges all contribute to the expense. The prefectural government's transport subsidies address one of those costs by helping move heavy material to recycling facilities.

Recovered glass has a low selling price. Scrap glass sells for about 0.5 to 1 yen per kilogram, leaving little income from the material itself to pay for collection, separation and processing. Companies are therefore looking for products with greater value and ways to reduce operating costs.

The insulation project brings those issues together. It needs a steady supply large enough for commercial production, an acceptable glass mixture and a financial arrangement that makes recycling workable. Subsidies can support the effort, while improvements in processing and a market for the finished insulation are also part of the solution.

Soma Combines Panel Reuse With Material Recovery

TAKEEI Corporation has launched a solar panel recycling facility in Soma City, Fukushima, using a device called the PV Recycling Hammer to crush panels and separate their glass. The plant can process about nine tons of panels a day, with plans to expand capacity.

The facility also checks whether panels can continue to be used. Panels that pass inspection are resold. Others are dismantled so that materials such as aluminum and glass can be recycled or responsibly disposed of.

Reuse gives a functioning panel another period of service before its materials need to be recovered. Promoting that option, especially in regions with less stringent performance requirements, is among the steps identified for managing the growing stream of retired equipment.

Fukushima's wider efforts include Soma Circular Park and the launch of web platforms for solar panel reuse and recycling. Together with the glass project, these initiatives reflect a growing effort to connect owners of retired panels with businesses that can reuse equipment or recover its materials.

Other Companies Are Testing Different Recovery Methods

AGC Inc. has succeeded in recycling solar panel cover glass into float glass, a product with greater value that is used in construction. Using recovered glass conserves raw materials and reduces greenhouse gas emissions because recycled glass requires less energy to process than virgin materials.

Mitsubishi Chemical Group has developed a different approach, using high temperatures to turn the panel sealant into gas. Removing that bonding material makes it easier to recover glass, silver, copper and aluminum.

The Mitsubishi Chemical process reduces recycling costs by 20 to 30 percent and allows about 99 percent of panel materials to be reused. Those figures address two central concerns for recyclers: how much material can be recovered and how much recovery costs.

NPC and Toshiba Environmental Solutions have developed mechanical approaches to separating glass from cells. These include the hot knife technique and grinding with steel brushes. Their work aims to make recycling operations more efficient and profitable.

The different technologies tackle different stages of the same problem. Separating tightly bonded layers produces recoverable materials; finding uses such as float glass or insulation gives manufacturers a reason to buy them. Both are needed when the value of ordinary scrap glass is so low.

Japan Is Preparing Mandatory Recycling Rules

The Ministry of Economy, Trade and Industry and the Environment Ministry plan to introduce legislation requiring companies to recycle solar panels, with penalties for failing to comply. Recycling is not currently mandatory, and most panels end up in landfills.

An expert panel is being convened to develop specific recycling methods and support measures, including financial assistance. The planned policy seeks to use resources more effectively, reduce environmental harm and bring Japan into line with international standards. No date for the legislation's introduction or implementation was given.

The European Union has required solar panel recycling since 2012. Similar regulations are being adopted in parts of the United States and considered in China. Japan's proposed requirements would place a legal obligation behind an activity that domestic businesses are already trying to make commercially viable.

The government is also promoting perovskite solar cells, or PSCs, a newer type of solar technology that is lighter and more versatile but has a shorter lifespan. Subsidies are being considered to cover recycling costs for these panels as well.

That work brings newer solar equipment into the disposal discussion while Japan is still preparing for the retirement of earlier installations. Recycling arrangements will need to account for the materials and useful lives of the technologies entering service.

What Fukushima's Effort Means for Japan

Recycling can reduce the volume sent to Japan's limited landfill sites, help prevent pollution from hazardous substances and recover glass, aluminum and silicon for further use. Replacing new raw materials with recovered ones also lowers energy consumption and can reduce greenhouse gas emissions.

The economic challenge remains substantial. Low material prices sit alongside high processing and transport costs. Government subsidies, new separation technologies and products with greater value are all being used to address that gap.

Fukushima's experience could provide a model for other regions because it combines renewable energy development with recycling infrastructure, cooperation between companies and prefectural support. Its position as Japan's leading prefecture for annual solar power generation makes the eventual handling of retired equipment a concrete local concern.

Japan's next tasks include expanding recycling capacity to handle hundreds of thousands of tons annually, improving processing technology, implementing and enforcing mandatory rules, developing valuable uses for recovered materials and encouraging reuse where possible.

Government, industry and research institutions will need to continue working together, alongside public support for sustainable energy practices. The Fukushima insulation trial shows one possible destination for panel glass. Its immediate test is whether a process using one ton a month can grow into an operation able to take at least 100 tons.

Key Points

• The Environment Ministry expects Japan to need to dispose of between 500,000 and 800,000 tons of solar panels annually from the late 2030s.
• Takaryo, Toshima Glass and Paramount Glass are testing the use of recovered panel glass in home insulation.
• Test production uses one ton of panel glass a month; Paramount Glass estimates commercial production needs at least 100 tons a month.
• Fukushima is subsidizing transport costs, while companies across Japan develop reuse, separation and glass manufacturing processes.
• Low scrap prices, processing costs and the difficulty of separating bonded panel layers remain major obstacles.
• Japan plans mandatory recycling legislation with penalties, while financial support and specific recycling methods are being developed.