About 770,000 tons worth of solar panels will end up in the garbage in Japan in fiscal 2040 after the end of their useful life, according to an Environment Ministry estimate.
Most old solar panels are now disposed of in landfill due to a lack of a framework for recycling or reusability, the ministry said, adding it plans to establish guidelines by next March on their disposal.
Some panels contain harmful materials such as lead and selenium and may pollute the environment, ministry officials said.
Since 2012, when utilities were obliged under the feed-in tariff system to buy all electricity generated from renewable sources at fixed rates, solar panels, whose average life is about 25 years, have been increasingly installed in houses and newly built power plants across Japan.
The amount of used solar panels is "expected to increase at an accelerated pace in line with the growing popularity" of solar power generation, the ministry warned.
The ministry estimates that around 2,400 tons of used solar panels will be generated as waste in the current fiscal year through next March, and the amount will surge to 28,000 tons in fiscal 2030. In fiscal 2040, such waste is expected to account for some 6 percent of all garbage dumped in Japan.
The European Union, which is advanced in the recycling of solar panels, obliges manufacturers to collect and recycle the panels under a 2014 law, according to the ministry.