OSAKA – Biocoke, a solid fuel made from plant waste, is gaining attention as a technology to help drive the shift to a low-carbon society. Developed in 2005 by Kindai University in Higashiosaka, Osaka Prefecture, it is a “dream solid fuel” that is said to emit virtually no carbon dioxide (CO2) when burning. is burned.

Japan’s catering sector and workshops in traditional industries are considering using biocoke as an alternative fuel, while research continues to reduce costs and move it to mass production.

In April, Oitomi, a traditional Nambu ironwork company in Oshu, Iwate Prefecture, tried to replace its usual coal coke with biocoke bricks made from apple lees and tree bark to melt the cast iron. Oitomi General Manager Akira Kikuchi evaluated the iron kettle, wind chime and paperweight produced in the experiment and concluded, “There were more sparks than with the coal coke alone, but there is no difference in quality.”

Oitomi typically consumes about 20 metric tons of coal coke per year. The workshop embarked on the biocoke experiment with Japan’s legal commitment to become carbon neutral – achieving zero net greenhouse gas emissions – by 2050 in mind. The CO2 emitted when vegetation is burned is not counted as an emission since it was originally extracted from the air by the plants. For this reason, it is said that biocoke emits practically no CO2 and should help to curb climate change.

Biocoke is made by shredding dried plant matter into particles a few millimeters in size and compressing it under immense pressure. The material is then heated to around 180 degrees Celsius and formed into cylinders. The combustion temperature of biocoke is over 1000 degrees Celsius, comparable to coal coke.

Kikuchi said the changing international situation has also prompted the traditional workshop to turn to biocoke. Japan depends on imports for most of its coal needs, with around 180 million tonnes of the product entering the country in 2021, according to preliminary figures. About 10% of that came from Russia. Since 2021, coal prices have surged and remained high. Then came the Russian invasion of Ukraine.

Prime Minister Fumio Kishida has announced that Japan will phase out imports of Russian coal, which could lead to further price hikes. Biocoke is less sensitive to international business flows than fossil fuels, and Oitomi plans to continue experimenting while keeping an eye on balancing costs.

The alternative fuel is even finding followers among major Japanese companies. Tokyo-based Mos Food Services Inc., which operates fast food chain Mos Burger, began selling drinks made from coffee beans roasted with biocoke at 48 Mos Burger & Cafe stores in March. The raw material used for the solid fuel is used coffee grounds.

A company representative explained: “As we considered renewing our range of coffees, we were inclined to adopt environmentally friendly products. We would like to consider expanding our use of biocoke.

In 2016 and 2017, Starbucks Coffee Japan Ltd. also collaborated with Kindai University and the Kobe municipal government on an experiment to produce biocoke from coffee grounds and other waste from its outlets.

The biggest obstacle to the success of biocoke is the cost of production. But Tamio Ida, director of Kindai University’s Biocoke Research Institute, pointed out that “technological innovation and soaring coal prices have brought biocoke (production cost) down to a reasonable level.” .

The most energy-consuming part of the production process is the pre-treatment of raw materials, including drying and grinding. According to Ida, costs can be reduced by selecting raw materials with low water content, such as buckwheat hulls and bran, and the outer skin of wheat, and those that do not need to be ground, such as used coffee grounds and tea leaves.

There are currently three companies producing biocoke. Since mass production is necessary to generalize it, the institute is researching ways to improve the performance of the fuel, such as increasing its energy value and developing production technology.

Ida commented, “We would also like to build a recycling-focused supply chain, where local waste is converted into biocoke and consumed locally.”

(Japanese original by Mai Suganuma, Osaka Science and Environmental News Department)