Font Size

HOME > No.27, Nov. 2021 > Making bio-gas power generation more accessible towards a carbon-free and recycling-oriented society

Making bio-gas power generation more accessible towards a carbon-free and recycling-oriented society

Yoichi Atsuta
Yoichi Atsuta

Renewable energy sources are increasingly being introduced as a means to achieve carbon neutrality. Among them, biomass energy sources are able to contribute to a carbon-free society and the effective use of waste, an issue that is attracting public attention. Toyohashi Biomass Solutions is involved in the bio-gas power generation-related business using waste biomass. They are working to ubiquitize bio-gas power generation through the development of ultra small plants, new technologies that improve the profitability of the power generation business, consulting with people about the introduction of biomass solutions, and other activities. We interviewed Yoichi Atsuta, the president of the company, about the key points of their technology and the society they aspire to establish.

Interviews and report by Akiko Seki

Harness the wind blowing toward bio-gas power generation

Biomass is used to refer to renewable biological organic materials that are not fossil resources. Biomass power generation is positioned as a renewable energy. It is generated by the direct combustion or gasification of wood biomass or by using bio-gas extracted from waste biomass such as livestock excrement, food waste, and sewage sludge through methane fermentation and other means. Dr. Atsuta established Toyohashi Biomass Solutions in May 2021 to operationalize bio-gas power generation plants, related technologies, and introduction consultations for bio-gas power generation methods. Dr. Atsuta told us that he decided to start the business because of changing social trends.

"Since around last year, the move toward carbon neutrality has been gaining momentum in Japan. This is a tailwind for bio-gas power generation, and I think now is the right time to introduce our unique plant to the world.

Dr. Atsuta is a visiting associate professor of Toyohashi University of Technology's Bio Research Center. The company, which was established on the premises of the university, is certified as a venture originating from Toyohashi University of Technology.

Methane fermentation (anaerobic digestion) is a collective name for the reaction processes in which methanogenic bacteria or other microbial communities decompose organic matter in anaerobic conditions to generate methane and CO2.

"Bio-gas power generation uses this process to extract bio-gasses including methane from livestock excrement, food waste, etc. to burn the gas in a gas engine. In addition to using waste as an energy source, it can also use the digested fluids after methane fermentation as liquid fertilizer because it contains a lot of nitrogen, potassium, and other nutrients. Returning it to agricultural land will lead to the creation of a resource-circulating society."

Because of these characteristics, bio-gas power generation has been widely adopted in Europe, where ecological awareness is high and there are active agriculture and livestock industries. However, it has not achieved great popularity in Japan because it requires a complicated system, expertise, and an initial investment. Plant facilities are mainly imported from Europe, and they are too big for agriculture and livestock operators in Japan, most of whom are running small operations. These problems must be resolved if bio-gas power generation is to become ubiquitous.

The development of new technology leading to ubiquitization

Dr. Atsuta has been very interested in environmental issues since he was a student. He began researching methane fermentation technologies after he took part in a bio-gas power generation demonstration experiment at a sewage treatment facility in Toyohashi-city when he was a researcher at Toyohashi University of Technology. When Dr. Atsuta was researching bio-gas power generation, he felt the need to resolve the problems in bio-gas power generation and launched a consortium with GENECH, etc., which he had become familiar with during the demonstration experiment. They jointly developed a small bio-gas power generation plant with a generation capacity of 20 to 30 kW, which is approximately one tenth that of conventional plants, and began selling it in 2016. The plants, which are called Toyohashi-model bio-gas power generation systems, have begun operating at six locations to date.

Dr. Atsuta has also worked on the development of new technologies. One such technology is an ammonia removal and collection system. During a reaction during methane fermentation, nitrogen and hydrogen bind together to generate ammonia. While ammonia is essential for methane fermentation, it inhibits fermentation when the raw materials contain a lot of nitrogen, which causes the ammonia concentration to be too high. Consequently, Dr. Atsuta developed a technology that volatilizes ammonia to remove and collect it and is now performing demonstration experiments. "Once this technology is put into practical use, it will be possible to use chicken droppings and other excrement that contains a lot of nitrogen to generate power, which means that the number of use-cases for bio-gas power generation will expand," Dr. Atsuta explained.

Another technology is the practical application of plants that are even smaller than the Toyohashi model. "The Toyohashi model is small, but it is still capable of processing 10 tons of biomass per day and includes a reinforced concrete fermenter. Many food factories and other facilities generate only approximately 1 to 2 tons of waste per day, so it is difficult for them to introduce the system unless the fermenter is made smaller. Because the fermenter is made of reinforced concrete, which requires construction, there is a loss of profitability as the size decreases, so together with Lemming Corp., we employed a general-purpose tank made of FRP as a fermenter and developed a plant that can be installed at a low cost"

Toyohashi Biomass Solutions provides these ultra-small plants to its customers. When customers require larger plants, they provide services in cooperation with the companies in the consortium.

Supporting the power generation gusiness using university-originated technologies and consultation

Toyohashi Biomass Solutions also developed an auxiliary agent for methane fermentation, as well as a quality control method for it, jointly with Komasuya Ltd. The auxiliary agent is generated through the lactate fermentation of food waste. Inputting an appropriate amount of the agent into a methane fermenter cab lowers pH, reduces the amount of ammonia that is generated, and increases the amount of bio-gas that is generated.

"Because bio-gas power generation is included in the FIT (feed-in tariff) targets, an increased volume of gas generated will increase the amount of power generated and purchased, which leads to the improvement of profitability"

One reason why bio-gas power generation has not caught on is that an advanced evaluation of its profitability is difficult because the volume of gas generated varies depending on the type of waste used as the raw material and other conditions. Dr. Atsuta performed fermentation tests with actually used raw materials and helps customers plan their business based on the bio-gas generation volume forecasts and consultations regarding compliance with laws and other regulations.

The lifecycle of a power generation business is calculated in units of 10 or 20 years. Dr. Atsuta also explained that he was operating his business from a long-term perspective.
"By accumulating best practices through the support of both hardware and software, including university-originated technologies based on scientific knowledge and consultations, I want to increase the accessibility of bio-gas power generation. I will develop a cycle for regional resource recirculation in cooperation with people in an array of industries, with the goal of achieving a society that produces less waste"


Dr. Atsuta's message to people who wish to start their own business

The important thing is to build connections with people. I would suggest that you connect with a wide range of people in government, industry, and academia. I have worked for a long time with a view toward starting my own business. However, I noticed that there were a lot of things I did not see because I was focused on getting it up and running. It was a long time before I started to feel that I was able to handle my business. However, because of that, I started my business at the best time. Even if you are ultimately unable to start your own business, I believe the experience will help you in the future.


熱田 洋一









一方、新しい技術の開発にも取り組んできた。一つは、アンモニアの除去・回収システムである。メタン発酵では反応の過程で窒素と水素が結合し、アンモニアが発生する。アンモニアはメタン発酵に欠かせないが、原料中の窒素が多いと濃度が高くなりすぎ、発酵を阻害してしまう。そこで熱田さんはアンモニアを揮発させて除去・回収する技術を開発し、実証実験を進めている。「この技術が実用化できれば、窒素含有量の多い鶏糞などもバイオガス発電に利用できるようになり、適用範囲が広がります」 と熱田さんは展望を語る。








(取材・文=関 亜希子)



Share this story

Researcher Profile

Yoichi Atsuta
Name Yoichi Atsuta
Affiliation Toyohashi University of Technology (TUT) and
Toyohashi Biomass Solutions, Co. Ltd.
Title Visiting associate professor of TUT
CEO of Toyohashi Biomass Solutions
Field of Business Material Cycles and Waste Management/ Environmental Science/ Anaerobic Digestion

Reporter Profile

Madoka Tainaka

Akiko Seki is a freelance writer. She graduated from Department of Applied Biological Science, Faculty of Agriculture at Tokyo University of Agriculture and Technology. She has worked on technical journals for major companies and has served reporting and writing in the field of science and technology.