According to a recent report by The Asahi Shimbun, Agile Energy X, a subsidiary of Tokyo Electric Power Company Holdings, has started exploring Bitcoin mining with the help of surplus green energy. 

The company has already set up mining equipment in Tochigi and Gunma prefectures. It focuses on the locations where it is possible to utilize excess renewable energy. 

Kyushu, the southwesternmost of the country's main islands, frequently has to deal with untapped electricity that gets generated from untapped energy sources. According to a 2021 report by The Mainichi, the equivalent of several nuclear reactors worth of generating capacity could be wasted within a day. 

Output controls require generating firms to stop producing additional output during periods of waning demand. This means that they have to discard surplus electricity. 

Kyushu started dealing with such measures back in October 2018. This was time time when Kenji Tateiwa, CEO at Agile Energy X, came up with the idea of using surplus energy for Bitcoin mining. The following year, the region had 74 days of output controls. 

Other Japanese regions, such as Shikoku and Hokkaido, have also faced similar problems. 

Last year, a whopping 1,920 gigawatt-hours of power were affected by output controls, according to The Asahi Shimbun.

For now, coal remains a key part of Japan's energy mix. However, with its gradual transition to renewable energy, the amount of wasted power is expected to increase. 

It could be possible to mine up to $2.5 billion worth of Bitcoin per year by utilizing 10% of the wasted power.