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Energy and resource consumption has been expanding quickly with the rapid growth of Asian cities, which has resulted in increased greenhouse gas emission and waste generation. The promotion of low-carbon industries is an urgent global issue that extends to Asia as well. To reduce carbon dioxide emission substantially, industries must not only introduce energy-saving technologies but also use low-carbon raw materials and fuel, such as recyclable wastes and carbon-neutral biomass. This paper presents the concept of a “hybrid industry,” that is, an industry whose processes utilize not only fossil resources but also recycled and renewable resources as much as possible. This study examines the feasibility of hybrid industries through the promotion of urban symbiosis in cities in three Asian countries with different circumstances: Kawasaki in Japan, Ulsan in Korea, and Shenyang in China. Asian cities are in the midst of shifting from dumping wastes to incineration. However, in view of the carbon reduction effect of recycling as well as the cost for recycling and appropriate treatment of wastes, the potential of hybrid industries that use combustible municipal wastes as input should be considered. In this study, the potential for carbon dioxide reduction as well as the costs of promoting hybrid industries are evaluated. The results highlight that promoting hybrid industries generates significant environmental benefits for the three cities, and there are important factors that affect the cost-effectiveness of hybrid industries, including the spatial density of waste generation, composition of wastes, relative labor cost for collection and pre-treatment of wastes compared with construction cost of an incinerator and avoided costs through product and fossil resource substitution, and the willingness of citizens to separate wastes. Finally, key drivers for promoting hybrid industries through urban symbiosis in Asian cities are discussed. [ABSTRACT FROM AUTHOR]

The spatial distribution of biomass resources is not uniform. At present, the zoning of biomass energy development suitability is primarily based on resource potential, whereas energy demand is ignored as an important factor affecting the degree of local energy self-sufficiency. Under the constraints of high transportation costs, solar energy with low geographical constraints can be a supplementary energy source for biomass despite its instability. Based on the energy utilization potential of solar energy and biomass resources, this paper evaluates the energy surplus factor (ratio of renewable resource potential to energy demand) of each city in the study area, takes meeting the specific energy surplus factor as the construction prerequisites of biomass combined heat and power (CHP) plants, calculates the biomass resource utilization rate and energy surplus factor in the study area under different conditions, and provides zoning suggestions and data reference for the unified planning of biomass CHP plants. The minimum energy surplus factor that is suitable for the development of biomass energy is set as the construction threshold of biomass CHP plants (The construction threshold is the minimum condition for the construction of biomass CHP plants. Only areas where the energy surplus factor reaches the preset construction threshold are allowed to build biomass CHP plants). The results show that the construction threshold is negatively correlated with the utilization rate of biomass resources. When the construction threshold is less than 1.4, the utilization rate of biomass resources decreases rapidly with the increase of the construction threshold; when the construction threshold is greater than 1.4, the utilization rate of biomass resources decreases slowly and tends to be flat. It is suggested that biomass resources should be developed in different regions and in stages, and priority should be given to developing areas with an energy surplus factor greater than 1.4. Areas with an energy surplus factor of 0.3–1.4 are considered secondary development areas, and areas with an energy surplus factor of less than 0.3 are not recommended for development; these can meet 31% and 59% of the total energy demand and reduce 50319380 tons and 180524400 tons carbon emissions so that the limited construction cost can meet higher energy demand and biomass resource utilization. • Priority development areas are identified based on solar and biomass potential. • Energy surplus factor is calculated to determine the development suitability. • Strategies for zoning and phased planning of biomass resources are proposed. [ABSTRACT FROM AUTHOR]

The accumulation of waste biomass and plastic and the inefficient combustion of low-quality coal is a major cause of energy loss and air pollution in rural China. This paper reports for the first time an experimental and multi-perspective analysis on an industrial scale co-pyrolysis of waste biomass and plastic. The results show that the resulting biochar product had a low calorific value of ≥21.0 MJ/kg, which meets the national standard for commercial solid fuel (GB/T 31862–2015). The calorific value of the produced gas was over 10 MJ/m3 and met the requirements of the national standard for residential heating and cooking (GB/T 13612–2006). The products of the co-pyrolysis can replace 1100 t of standard coal per annum, and reduce carbon dioxide emissions, sulfur dioxide emissions, smoke, and other contaminants at the rate of 1720 t, 5–6 t, and 320 kg, respectively, as well as reducing smoke pollution. In addition, through the recycling of 750 t of plastic waste per annum for use in the co-pyrolysis, this method can reduce the white pollution of 50–66.7 km2 of farmland in the local area. The present study can guide the optimization of such systems and lead to adequate flexibility in the co-pyrolysis of different wastes to generate economic and socioenvironmental benefits. Image 1 • Industrial co-pyrolysis of biomass, waste agricultural film, and low-quality coal. • Systematic analysis of energy flow and economic and socioenvironmental benefits. • Biochar and fuel gas calorific values reached 21.0 MJ/kg and 10 MJ/m3, respectively. • The project annually reduces 1100 t of coal combustion and 1720 t of CO 2 emissions. • Recycling agricultural film reduces white pollution on 50–66.7 km2 land annually. [ABSTRACT FROM AUTHOR]