**Energy Rings Around the Earth: The Challenge of Shunan City, Yamaguchi Prefecture - May 2003**.

**Energy Rings Around the Earth: The Challenge of Shunan City, Yamaguchi Prefecture - May 2003**.
In the early 2000s, as Japan was about to enter into force of the Kyoto Protocol, it was required to reduce greenhouse gas emissions and accelerate the introduction of renewable energy. In the midst of this trend, Shunan City in Yamaguchi Prefecture was a pioneering attempt born from a rural area to develop a regional recycling-oriented agriculture and biogas power generation system. Biogas produced by methane fermentation of livestock waste and agricultural residues was converted into electricity by a generator, supporting local lifestyles. Not only did it replace fossil fuels, it also reduced the burden of waste disposal and expanded the circle of recycling.
The digested liquid left over after fermentation was returned to farmland as a highly effective fertilizer resource. It served as a substitute for chemical fertilizers, reducing the environmental impact of the production process and helping to keep the soil healthy. In addition, the fermentation process helped to alleviate odors around livestock facilities and protected rivers by preventing manure runoff.
At the time, such biogas facilities were still rare in Japan, and the technology was adapted to local conditions in Japan, referring to examples in Germany and Denmark in Europe. Technologies such as temperature control of anaerobic fermentation tanks, gas purification, power generators, and solid-liquid separation were combined to create a new form of circulation that links the earth and human life.