Introduction
Materials and methods
Definition of GHG emissions in the material cycles and waste management sector
Sector | Categories | GHG emission sources |
---|---|---|
Waste | GHG emissions from solid waste | Solid waste disposal (CH4), biological treatment of solid waste (CH4, N2O), incineration and open burning of waste (CO2, CH4, N2O) |
Energy | GHG emissions from waste incineration with energy recovery and waste utilization as raw material or fuel | Waste incineration with energy recovery (CO2, CH4, N2O), direct use of waste for energy (CO2, CH4, N2O), waste derived fuel (CO2, CH4, N2O) |
Energy | CO2 emissions from the use of energy required for waste treatment | Electricitya and other energy consumption during waste collection, intermediate treatment, and final disposal of solid waste (CO2) |
Equation for GHG emission estimation and future GHG estimation methods
Municipal waste
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Future municipal waste generation was calculated by multiplying the future population shown in the “National Institute of Population and Social Security Research, Estimated Future Population of Japan (2017 Estimates)” [16] by the unit municipal waste generation per person per day.
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Future municipal waste generation by waste composition was estimated by multiplying future municipal waste generation by future municipal waste composition.
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Future municipal waste generation by waste composition and treatment methods were estimated by multiplying the fractions of future waste treatment methods by waste composition and future municipal waste generation by waste composition.
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Future GHG emissions from municipal waste were estimated by multiplying future municipal waste generation by waste composition and treatment methods and future GHG emission factors.
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The amount of treated municipal waste and human waste [by waste treatment technologies, size of facilities, and facility installation (new/existing)] were estimated based on future municipal waste generation by waste composition and treatment methods, shown in the above procedure.
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Future CO2 emissions from energy use in municipal waste treatment were estimated by multiplying the amount of treated municipal waste and human waste and future unit energy consumption by facility types with future CO2 emission factor.
Industrial waste
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Future industrial waste generation by waste type was estimated by multiplying future industrial waste generation by waste type in each industrial sector and future activity drivers (e.g., future material production) [17].
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Future industrial waste treatment by waste type and treatment methods were estimated by multiplying future industrial waste generation by waste types and fractions of future industrial waste treatment methods (landfill, composting, and incineration).
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Future GHG emissions from industrial waste were estimated by multiplying future industrial waste treatment by waste type and treatment methods and future GHG emission factors by waste type.
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Future energy consumption in industrial waste treatment (by waste type and treatment methods) was estimated on the basis of future industrial waste treatment by waste type and treatment methods and future unit energy consumption in industrial waste treatment.
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Future CO2 emissions from energy use in industrial waste treatment was estimated by multiplying future energy consumption in industrial waste treatment (by waste type and treatment methods) and future CO2 emission factors.
Methods of reducing GHG emission
Medium- to long-term scenario
Name | Description |
---|---|
BAU (business-as-usual) Scenario | • Assumes current measures (as of around FY2019) will remain unchanged until 2050 • Estimated GHG emissions in the following scenarios are in comparison with the BAU scenario |
Planning Scenario | • Assumes the implementation of existing government plans/regulatory frameworks and industry efforts for GHG emission reductions and material cycles (Japan’s National Climate Action, Resource Circulation Strategy for Plastics, Roadmap for Bioplastics, Act on Promotion of Resource Circulation for Plastics, industry targets, etc.) |
Expanded Planning Scenario | • Assumes that in addition to the Planning Scenario, additional measures are taken to reduce energy-related CO2 emissions from waste treatment emissions from waste treatment facilities, waste collection/transport vehicles, etc. |
Innovation Scenario | • Building upon the Expanded Planning Scenario, assumes further GHG emission reductions through technical innovations in each priority area, gauged realistically considering current innovation trends, etc. |
Advanced Innovation Scenario | • Building upon the Innovation Scenario, assumes further progress, gauged more optimistically based on current innovation trends |
Net Zero Emissions Scenario | • Building upon the Advanced Innovation Scenario, assumes waste treatment facilities will adopt CCUS (actually, CCS for this scenario)a to completely offset GHG emissions from the material cycles and waste management sector |
Maximum Actions Scenario | • Building upon the Net Zero Emissions Scenario, assumes waste treatment facilities will use CCUSa to the maximum possible |
Emission quantification parameters
Decarbonization of the entire life cycle of each material through material cycles
Type of measures | Specific measures to be taken |
---|---|
Promotion of reducing, reusing, and separate collection | Charging for plastic shopping bags under Cabinet Order on the Containers and Packaging Recycling Act Reduction of designated plastic products ((14 items such as forks and straws) under the Plastic Waste Recycling Promotion Act The generalization of these efforts for reducing plastics |
Further promotion of material recycling | Promotion of environmentally friendly design of plastic products and promotion of separate collection of waste plastics in accordance with the Plastic Resource Circulation Act Upgrading of sorting technology and systems to promote the use of recycled products |
Promotion of circular chemical recycling | Promotion of circular chemical recycling Improvement of yield ratio in the chemical recycling process The development of a system to increase the recycling value of plastic products, and efforts to increase waste plastics for circular chemical recycling |
Further promotion of biobased plastics | The Innovation scenario assumes the introduction of approximately 2.5 million tonnes of biobased plastics in 2050 (assuming 2.5 million tonnes of biomass content) In the transitional period before full-scale introduction of biobased plastics, the use of polypropylene, polyethylene and other materials with the mass balance approach is expected |
Developing a waste management system that contributes to regional decarbonization
Decarbonization of waste treatment facilities and vehicles
Results and discussion
Estimated GHG emission by scenario by 2050
Key measures for waste plastics and the projected decreasing courses by 2050
Key measures for waste oil
Key measures for municipal solid waste treatment and disposal
Potential reduction by more material cycles and resource efficiency
(ktCO2) | Scenarios | |||||
---|---|---|---|---|---|---|
BAU | Expanded planning | Innovation | Advanced innovation | Net zero emissions | Maximum actions | |
GHG reduction actions | ||||||
Waste plastics | 0 | 7983 | 12,406 | 13,690 | 13,690 | 13,690 |
Waste oil | 0 | 408 | 4777 | 5838 | 5838 | 5838 |
Waste paper | 0 | 0 | 638 | 865 | 865 | 865 |
Disposable diapers | 0 | 0 | 820 | 820 | 820 | 820 |
Synthetic fiber scraps | 0 | 0 | 458 | 601 | 601 | 601 |
Scrap tires | 0 | 0 | 403 | 504 | 504 | 504 |
Other actions | 0 | 941 | 1068 | 1119 | 1119 | 1119 |
Actions for energy-related CO2 | 0 | 2456 | 2898 | 4367 | 4367 | 4367 |
CCUS | 0 | 0 | 0 | 0 | 6164 | 16,138 |
Total | 0 | 11,788 | 23,469 | 27,805 | 33,968 | 43,943 |