TOKYO -- Solar panels have sprung up across Japan in the past few years, after the government introduced a "feed-in tariff" in July 2012 that guarantees prices for electricity generated from renewable energy. When these panels reach the end of their working lives in 20-30 years, they will create a mountain of waste.
By 2020, Japan's Environment Ministry forecasts the country's solar-panel waste will exceed 10,000 tons. After that, the pile really starts growing: reaching 100,000 tons in 2031 and topping 300,000 tons in 2033, the 20th anniversary of the feed-in tariff. Between 2034 and 2040 the amount of waste produced is expected to hover around 700,000-800,000 tons annually. The projected peak of 810,000 tons is equivalent to 40.5 million panels. To dispose of that amount in a year would mean getting rid of 110,000 panels per day.