TOKYO — The Japanese government is rushing to expand solar power generation to drastically cut the country’s greenhouse gas emissions, but the plants already in operation are aging. As there is limited room to build new large-scale solar plants, businesses keeping generating efficiency high and existing facilities online long term are booming.
About 18,000 solar panels blanket a vast field in the town of Shibayama, Chiba Prefecture, about 5 kilometers southeast of Narita Airport. If you look closely, you can see white dots here and there on the panels.
“They’re bird droppings. If not cleaned up, the stuff will accumulate and cause hot spots,” said Masafumi Oshiro, general manager of the investment management department of SBS Asset Management Co., a logistics facility development company based in Tokyo’s Sumida Ward that operates this mega-solar plant.
“Hot spots” here refers to when bird droppings, fallen leaves and other factors cause increased electrical resistance in solar panels, resulting in heat. Not only does this reduce power generation efficiency, but it can also lead to panel failure and fires.
Bird droppings dot some of the solar panels in Shibayama, Chiba Prefecture, on July 15, 2021. If not cleaned off, the droppings can lead to decreased power generation efficiency and panel failure. (Mainichi/Ei Okada)
This power plant went online in 2013, and according to Oshiro, hot spots, rust and dirt became noticeable from around the fifth year of operation. An examination of the plant’s output found that its power generation efficiency — the amount of electricity generated per quantity of solar radiation — had dropped about 10% by 2019, the plant’s seventh year. That amounted to more than 10 million yen (about $89,920) in lost electricity sales revenue per year.
The company operates 14 solar power plants across Japan, and power generation efficiency had been declining at an average rate of 1.6% per year as of the end of 2018. Washing the panels with water at nine locations, including a facility in Shibayama, improved the power generation efficiency at eight of them.
The government’s goal is to reduce greenhouse gas emissions by 46% by fiscal 2030 compared to fiscal 2013 levels. The Ministry of the Environment has announced a proposal to add 20 million kilowatts to the current target of 64 million kilowatts of solar generating capacity in fiscal 2030.
With the introduction of the feed-in tariff (FIT) system in 2012, the construction of mega-solar power plants took off in many areas, but the pace has stalled since. The number of suitable sites for …….