Could Japan’s waste-to-energy technology help countries address their waste and energy problem while tackling the climate crisis by reducing waste and generating clean energy?
Our waste problem is increasing. Plastic waste has become a severe environmental issue.
According to a Plastic Collective article, “The Plastic Waste Problem and its Solutions”, we produce 300 million tonnes of plastic, and 14 million tonnes of it end up in the oceans.
Plastic waste decomposes slowly and takes anywhere between twenty and five hundred years to do so. Our World in Data shows that 55% of these plastics end up in landfills, and 25% end up in incinerators. However, incinerating them also sends enormous amounts of GHG into the atmosphere – around 850 million tonnes per year.
Aside from plastic, we generate other types of waste, generally grouped as municipal solid waste (packaging, furniture, bottles, clothing, food scraps, appliances, etc), industrial waste (plastic, glass, etc.), agricultural waste (cattle waste, weed, husk, etc) and hazardous waste (pesticides, motor oil, car batteries, paint, and solvents, etc).
Japan’s big cities are densely packed and generate vast amounts of waste. Their cities also require a significant supply of energy. Some lack recycling facilities, and those that utilize incineration plants must dispose of their ash waste in landfills. It is challenging for some cities that lack the space to accommodate this.
Gasification or direct melting system (DMS) is a more environmentally friendly alternative to conventional incinerators for these cities.
Advantages of gasification
Nobuhiro Tanigaki, Senior Manager at Nippon Steel Engineering, the market leader in Japan, which has built more than 50 gasification plants, explains the benefits of using a direct melting system (DMS). According to an article, the “final landfill amount from grate in Japan is approximately 15%, while the final landfill from our Direct Melting System is only 3%. It contains only the Air Pollution Control residue, whereas the landfill from conventional grate technology contains bottom ash and APC residue.
The gap is the benefit as the landfill costs of bottom ash and APC residue are almost the same. In addition, DMS co-gasification of other difficult-to-treat waste, such as rejects from recycling centres and incombustible or reclamation waste, would help to minimize the final landfill as well (Waste to Energy, 2023).
When did the waste-to-energy start in Japan?
During the oil crisis, Japan developed energy recovery technology from waste in the 1970s. Interest increased in converting household waste into energy and recycling resources. Nippon Steel & Sumikin Engineering Co., Ltd. introduced the Direct Melting System (DMS), a gasification and melting technology, in 1979 in Kamaishi city. Since then, the technology has been used commercially for 40 years at more than 50 sites in Japan.
DMS capacities range from 10,000 to 230,000 tonnes of waste per year. DMS facilitates a zero-waste policy thanks to the almost 100% reusability of the end products. Additionally, due to the high temperatures of the DNS, the system can treat all types of waste, from household waste to bottom ash, particular waste to clinical waste and the gasification of sewage sludge. The energy produced from the plants is fed into the public grid.
Can technology benefit other countries that have issues similar to Japan’s?
According to the Waste Management World article, the main objections to gasification are its costs – it is too expensive, maintenance intensive, and inefficient compared to conventional incineration plants, which is why only gasification applications in high-income countries account for 2%. In contrast, in low-income countries, it is non-existent.
While incinerators are widely used in Japan, gasification and direct melt occurred when the government required that the ash from incinerators be melted to reduce the ash residues, leading them to develop a two-stage waste treatment process.
The United Nations Industrial Development Organization article explains how the two-compartment combustion system works. In this system, “gasification and combustion occur in two different compartments. The separated compartments contribute to the efficient combustion of waste (the combustion efficiency is almost 100%, and the loss on ignition is 3% or less.) into usable energy such as electricity, steam, hot water and hot wind. Stable combustion can be achieved in tightly sealed compartments and reduces fossil fuel use.”
In addition, “the resulting inorganic ash can be safely recycled. They are used as a material to compose cement and pavement.”
Japan’s waste-to-energy technology could benefit the rapidly growing amount of waste worldwide and the need to dispose of it sustainably and in a way that does not pollute the environment or add to global emissions. With continuous technological improvements, it can become a viable and feasible waste disposal and energy source for other countries in the near future.
DMS has been successfully implemented in Japan due to its extremely restrictive landfill policy, which stems from waste management system laws, which allowed it to overcome the technological challenges of building and applying gasification.
For example, municipalities must create a long-term waste management plan for at least the next ten years and treat and recycle their waste. Japan’s geography is also another contributing factor. It limits their use for landfills, which makes DMS a viable alternative.
Waste to energy: Lessons from Japan. (2023, May 10). Waste-Management World. Retrieved from https://waste-management-world.com/waste-to-energy/waste-to-energy-lessons-from-japan/
Waste Gasification Technology (Direct Melting System). (n.d.) Steinmüller Babcock Environment. Retrieved from https://www.hzi-steinmueller.com/wp-content/uploads/downloads/broschure-waste-gasification-en.pdf
Eco-Friendly Waste Gasification & Incineration System for Energy Generation. (n.d.). United Nations Industrial Development Organization. Retrieved from http://www.unido.or.jp/en/technology_db/1647/