Development and Implementation of a Used Cooking Oil Recycling System – Yakushima Town, Kumage District, Kagoshima Prefecture (July 1999–December 2024)

Development and Implementation of a Used Cooking Oil Recycling System – Yakushima Town, Kumage District, Kagoshima Prefecture (July 1999–December 2024) In Yakushima Town, Kumage District, Kagoshima Prefecture, a system for recycling waste cooking oil as an alternative to diesel fuel was developed in the late 1990s. This system refines used cooking oil and reuses it as fuel for diesel engines, eliminating sulfur oxide (SOx) emissions and reducing black smoke emissions to one-third of conventional levels. Through collaboration between Kagoshima University and local businesses, the technology was adopted for public buses and agricultural machinery. As a result, the region’s annual fuel costs were reduced by 20%, achieving both environmental conservation and economic benefits. **Initiatives in the 2000s** In the 2000s, Yakucho’s used cooking oil recycling technology began to spread widely. In 2003, the **Yakushima Environmental Energy Center** was established, and a facility capable of processing approximately 10,000 liters of waste cooking oil annually began operations. The refined biodiesel fuel (BDF) was used in buses operated by Yakushima Kotsu Co., Ltd. and in agricultural machinery operated by the Yakushima Agricultural Cooperative, contributing to a reduction in fuel transportation costs. Furthermore, a waste cooking oil collection system was established, with the amount collected from local restaurants and households reaching approximately 8 tons per year. In 2005, efforts began to utilize recycled fuel as marine fuel for the tourism industry, contributing to the development of sustainable tourism. **Developments in the 2010s** In the 2010s, waste cooking oil recycling technology continued to advance. In 2012, **Yakushima Eco Energy Co., Ltd.** introduced a biodiesel fuel production plant, expanding its processing capacity to approximately 30,000 liters per year. This fuel was used in tourist buses and generators at public facilities, achieving a CO₂ emission reduction rate of approximately 40% compared to conventional fossil fuels. In 2015, a used cooking oil collection campaign targeting local residents and tourists was launched, resulting in annual collection volumes exceeding 12 tons. Furthermore, in 2013, Yakushima Town was recognized by the Ministry of the Environment as a “Circular Economy Model Community,” bringing national attention to the used cooking oil recycling system. Fuel derived from waste cooking oil has become indispensable to local industries and transportation infrastructure, and has also gained widespread recognition in the tourism sector as part of “ecotourism.” **Current Status in the 2020s** In the 2020s, technological innovations and the introduction of digital management have further streamlined waste cooking oil recycling on Yakushima. Yakushima Eco Energy Co., Ltd. introduced an AI-powered waste oil collection system, improving collection efficiency by 20%. As of 2023, the annual processing volume has reached approximately 50,000 liters, and the system operates stably as a fuel source for Yakushima Transportation Co., Ltd. and the local agricultural cooperative. Furthermore, the recycled fuel is used for Yakushima’s power supply, and a biomass power plant has begun operations. In this way, starting with technological development in the 1990s, followed by widespread adoption in the 2000s and further advancement in the 2010s, waste cooking oil recycling has become firmly established throughout the entire local community in the 2020s. Moving forward, efforts to maximize the use of local resources and achieve both environmental conservation and sustainable economic development are anticipated.