Biogasification of food waste contributes to waste reduction and decarbonization
Biogas is generated by fermenting food waste and used as a renewable energy source. Mitsui's methane fermentation biogas power generation business is promoting the introduction of such biogas facilities, mainly in food factories. Food waste has rarely been recycled as biogas until now, but we spoke with a person in charge about the possibilities and challenges of methane fermentation biogas power generation, which offers a new option.
Mitsui's Chubu Branch is working on a methane fermentation biogas power generation project as one of its decarbonization solutions. Although this project has been under full-scale study for only about a year, we are able to propose biogas facilities with a high return on investment by collaborating with multiple vendors of biogas facilities, selecting the most suitable vendor, and designing the plant. In addition to its economic rationality, the biogas power generation business is attracting a great deal of interest, especially from food companies, because of its significant environmental benefits, such as reduction of food waste and CO2 emissions.
--What is the story behind your focus on the methane fermentation biogas power generation business and how did you start working on it?
Baba: The Business Promotion Office of the Chubu Branch has been providing decarbonization solutions such as solar power generation and renewable energy sales through PPA across the Mitsui & Co. group for some time. Among the various consultations we received from customers regarding decarbonization, we were also asked about food waste and biogas. We began researching from scratch, and through visits to various biogas facilities, we identified and selected vendors and were able to introduce biogas facilities that meet the challenges and needs of our customers.
Takanori Baba, General Manager, Business Development Office, Chubu Branch Office and Business Development Office, Kansai Branch Office, joined Mitsui & Co. Since joining Mitsui & Co., he has worked in trading of fertilizer raw materials, launching of AdBlue® sales business to reduce NO He is currently focusing on developing new business with local companies and municipalities under the regional strategy of "proposing carbon-neutral composite solutions" in the Chubu region, which is a center of manufacturing.
Reduction of food waste and processing costs through the use of biogas / Reduction of energy costs through the use of renewable energy / Reduction of CO2 emissions
--What are the main users of biogas and why did you introduce it?
Nonaka: Currently, the system is being used mainly by food companies that are facing challenges with food waste. By generating biogas from food waste from their own factories and using it, food waste can be reduced and disposal costs can be cut at the same time. In addition, the biogas generated can be used as a renewable energy source for in-house power generation and other purposes, leading to reduced energy costs and CO2 emissions.
Toshinari Nonaka, Business Promotion Office, Operations Department, Chubu Branch Office, Mitsui & Co. After joining the company, he worked in the ICT Business Division, importing and exporting computer hardware and software, investing in IT-related ventures, and was transferred to Mitsui Knowledge Industry before being transferred to the Chubu Branch Office in 2020. He has been promoting sales activities to respond to the issues of food waste reduction, CO2 emission reduction, and resource recycling in the corporate sector.
--What is the current situation in the recycling of food waste?
Mori: There are about 16 million tons of commercial food waste annually, but about 60% is recycled as feedstuff or fertilizer, and only about 3% is used as biogas. I believe that recycling as biogas is still not widely recognized.
Yasuyo Mori, Business Promotion Office, Administration Department, Chubu Branch Office, Mitsui & Co. After joining the company, she experienced domestic logistics operations and import/export operations in the Chemicals (PM Division) Department. After a five-and-a-half-year secondment to Mitsui & Co. Plastics Ltd., she was transferred to the Operations Office of the Operations Department in November 2016, where she was in charge of secretarial duties for the Branch Manager and General Manager. From February 2022, she was transferred to the Business Promotion Office, where she is in charge of developing new businesses related to biogas and hydrogen.
--What are the advantages of biogas conversion?
Nonaka: There are four major advantages of biogas conversion. Since food waste is processed in a biogas facility, the final amount of waste is reduced, enabling a "reduction in waste disposal costs. In addition, the fermentation residue that remains after gas generation may be used as compost or animal feed, so a "resource recycling" model can be established for this part of the process. Furthermore, the biogas generated can be used as "renewable energy" for power generation and other purposes, enabling "reduction of CO2 emissions. The reduction of CO2 emissions from waste disposal and the use of renewable energy in place of fossil fuels can greatly reduce overall CO2 emissions.
Converting 5 tons/day of food waste to biogas can reduce about 200 t-CO2/year
--How much CO2 emission reduction will be possible?
Nonaka: The CO2 reduction target for food factories is generally on the order of 1,000 to 2,000 t-CO2(*1) per year, but if 5 tons/day of food waste is converted to biogas, the annual reduction will be about 200 t-CO2. This means that about 10-20% of a food factory's CO2 emissions can be reduced through biogasification.
This is comparable to the annual reduction effect of 150 t-CO2 per 3,000 m2 roof area of roof-mounted photovoltaic power generation, which is often used as a CO2 emission reduction measure in factories. This is also an effective solution for factories that are unable to install more solar power generation.
(*1) t-CO2: A unit for one ton of carbon dioxide in greenhouse gas em issions.
--What is the payback period for the investment?
Nonaka: We propose a payback period of 5 to 7 years for the installation of a facility to ferment food waste to generate biogas in the plant. The vendors we work with have the technology to efficiently generate the gas, and we can propose facilities that are economically rational. In fact, in many cases, we have been able to achieve a return on investment in a relatively short period of time through in-house power generation using biogas and reduced waste disposal costs. In addition, we support our clients in obtaining government and municipal subsidies, as well as leasing in cooperation with our group companies, making it possible to reduce the initial cost of introduction.
The amount of gas generated depends on the type of food waste used as raw material.
--It is fascinating from all points of view. What would you check to see if you are considering implementing this program?
Mori: First, we check the type and amount of food waste generated by the factory. This is because the amount of biogas generated and its stability (i.e., whether the amount of gas generated is stable or fluctuating) depends on the type and amount of food waste handled at the factory. For example, mixed food wastes such as prepared foods and boxed lunches tend to generate gas stably, while cookies, rice crackers, and other snacks generate a large amount of gas per volume, but depending on the raw material, gas generation may be difficult or pre-processing may be costly to make gas generation easier.
--With companies making efforts to reduce food waste, the amount of waste may be decreasing.
Nonaka: As you mentioned, companies are making efforts to reduce waste, so the amount of food waste is decreasing. Therefore, more and more smaller facilities are being introduced for food factories to match the amount of waste.
Biogas facility on a limited site Flexible design
--What are some of the challenges you faced when introducing the system?
Mori: You will need to secure a space for the installation of a biogas facility. Ideally, a small plant would require an installation site of about 10 m x 17 m near the waste discharge point or wastewater treatment facility, which would need to be secured within the existing plant site. However, the biogas facilities handled by our office can be flexibly arranged and designed, including some degree of shape modification.
--Once again, how does biogas power generation work?
Nonaka: First, water is added to the food waste as raw material to raise the moisture content to over 90%. Heat is then added, and the mixture is stirred to ferment. The biogas generated by this process is stored in a tank and used as fuel for an attached power generator in many cases. Of course, it can also be used as heat in boilers or as gas by increasing the methane concentration.
--What is the reuse of fermentation residues?
Nonaka: The residue after fermentation can be recycled as a resource in the form of liquid fertilizer or solidified by removing water and used as fertilizer.
A team capable of solving any customer issue
--What are Mitsui's strengths in the methane fermentation biogas power generation business?
Baba: Mitsui & Co. provides comprehensive support for decarbonization, not only in the methane fermentation biogas power generation business, but also in the visualization of CO2 emissions, the introduction of renewable energy sources such as solar power, and carbon offsetting initiatives using forest credits and other resources. Our office in the Chubu Branch is a small organization of 12 people, but we are a group of members with various business backgrounds who work with the Mitsui & Co. group and can each speak about decarbonization solutions in their own words. This is our strength and allows us to support decarbonization not by selling what we want to sell, but by solving our clients' business challenges and taking a stance of being close to them.
Nonaka: Against this backdrop, it is common for customers to calculate their own CO2 emissions, research decarbonization solutions, and select vendors themselves, but Mitsui can take care of all of these tasks through cross-divisional and group collaboration. In addition to providing sales support to biogas facility vendors by introducing biogas facilities to Mitsui & Co. group clients, we can also provide multifaceted support, including coordination of technical requirements and specifications for facility introduction and support for introduction of government subsidies.
Small to medium sized biogas facility fits Japan
--What is the current status of biogas facilities and what is the situation overseas?
Nonaka: Biomass energy overseas, especially in Europe and the United States, is based on the concept of producing grains for energy (inedible grains) on a large scale and using them as raw materials, and commercial use of small- and medium-scale biogas facilities is limited. In Japan, the idea is to obtain biomass energy from waste as a raw material, and although the scale is smaller than in Europe and the U.S., we believe that this is an important initiative to increase environmental value from the perspective of waste reduction. In the future, we are considering applying Japanese resource recycling technology to large-scale projects overseas.
Mori: The number of biogas facilities in Japan is still small, but with the development of small and medium-sized facilities with high economic rationality and growing environmental awareness, many companies, especially food companies, are taking an interest.
--Are there any new services you would like to work on in the future?
Nonaka: When biogas is generated, CO2 is emitted at the same time as methane, and technologies to convert this CO2 into methane (methanation) are emerging. We would like to actively incorporate such new technologies to achieve more efficient resource conversion. In terms of resource recycling of fermentation residues, we would like to expand the scope of our activities from the perspective of resource recycling by incorporating new technologies such as carbonization, in addition to conversion to feed and fertilizer.
--Lastly, please tell us about the future you hope to achieve through this project.
Baba: Business-related food waste in Japan alone amounts to 16 million tons per year. In response to this situation, we hope to reduce food waste and promote resource recycling through our methane fermentation biogas power generation business, as well as provide multifaceted support for the decarbonization of each company by leveraging the comprehensive strengths of the Mitsui & Co. group. Through such activities, we hope to encourage the resolution of social issues facing Japan and the world.
--Thank you very much for your time today.
We provide comprehensive support for decarbonization, including biogas. Please feel free to contact us for more information!
