Towards inclusive green growth: does digital economy matter?

In this decade, China has been pursuing an inclusive green growth strategy. Concurrently, the digital economy, which relies on the Internet of Things, big data, and artificial intelligence, has experienced explosive growth in China. The digital economy's capacity to optimize resource allocation and reduce energy consumption potentially makes it a conducive channel towards sustainability. Using the panel data of 281 cities in China from 2011 to 2020, we theoretically and empirically explore the impact of the digital economy on inclusive green growth. Firstly, we theoretically analyze the potential impact of the digital economy on inclusive green growth using two hypotheses: accelerating green innovation and promoting the industrial upgrading effect. Subsequently, we measure the digital economy and inclusive green growth of Chinese cities using Entropy-TOPSIS and DEA approaches, respectively. Then, we apply traditional econometric estimation models and machine learning algorithms to our empirical analysis. The results show that China's high-powered digital economy significantly promotes inclusive green growth. Moreover, we analyze the internal mechanisms behind this impact. We find that innovation and industrial upgrading are two plausible channels that explain this effect. Additionally, we document a nonlinear feature of diminishing marginal effects between the digital economy and inclusive green growth. The heterogeneity analysis shows that the contribution weight of the digital economy to inclusive green growth is more remarkable in eastern region cities, large and medium-sized cities, and cities with high marketization. Overall, these findings shed more light on the digital economy-inclusive green growth nexus and provide new insights into understanding the real effects of the digital economy on sustainable development.

Impact of technological innovation and industrial-structure upgrades on ecological efficiency in China in terms of spatial spillover and the threshold effect.

In the past 40 years, China's rapid industrialization has resulted in remarkable social progress and regional economic prosperity but also has caused problems, such as excessive resource consumption and environmental pollution. Ecological efficiency is an important indicator of whether economic efficiency and environmental efficiency are balanced. Exploring ecological efficiency is vital for achieving sustainable development, as technological innovation, industrial structure upgrading, and ecological efficiency are probably related. However, there has been little research on the relationships among them. In this study, we used the super-efficiency slacks-based model (SBM) involving undesirable output to calculate the ecological efficiency of 30 provinces in China from 2008 to 2017. We found that China's ecological efficiency has risen, fallen, then fluctuated, and that there were significant spatial differences. Then, we used 3 spatial econometric models for comparative analysis, which revealed that the independent effects of technological innovation on ecological efficiency was significant and negative; however, technological innovation demonstrated a strong positive effect in tandem with industrial structure upgrading, and industrial structure always had a positive effect on ecological efficiency. On this basis, we added the cross-item of technological innovation, and industrial-structure upgrades had a significant and positive impact on ecological efficiency, which was significantly greater than the independent effect of technological innovation and industrial-structure upgrades. To explore the mechanism of industrial-structure upgrading and technological innovation on regional ecological efficiency, we set the first 2 as threshold variables. We found that there is in fact a threshold effect of technological innovation and industrial-structure upgrading on ecological efficiency due to the mismatch of periods. These results provide a theoretical rationale for China to formulate strategies to improve ecological efficiency. Integr Environ Assess Manag 2021;17:852-865. © 2020 SETAC.

Waste-to-biofuel integrated system and its comprehensive techno-economic assessment in wastewater treatment plants.

Combining wastewater treatment and biofuel production is considered the cost-effective way for better waste remediation and lowering the environmental impact for biofuel production. In this study, an innovative integrated system incorporating sludge, scum and centrate treatment and biofuel production was developed. A comprehensive techno-economic analysis was conducted to evaluate the technology and economic feasibility of the integrated system with the consideration of biofuel production, wastewater treatment improvement, tax credits, carbon credit, and coproducts utilization. Benefited from the integrated system that the intermediate byproducts can be used in between the sub-systems, such as the glycerol generated from the scum-to-biodiesel production can be used as an organic carbon for the centrate-to-algae production, the estimated breakeven selling price of the bio-oil ($1.85/gallon) is very close to the 5-year averaged crude oil price. The assessment result showed the payback period and the IRRs of the integrated system are superior in comparison with others.

Comprehensive techno-economic analysis of wastewater-based algal biofuel production: A case study.

Combining algae cultivation and wastewater treatment for biofuel production is considered the feasible way for resource utilization. An updated comprehensive techno-economic analysis method that integrates resources availability into techno-economic analysis was employed to evaluate the wastewater-based algal biofuel production with the consideration of wastewater treatment improvement, greenhouse gases emissions, biofuel production costs, and coproduct utilization. An innovative approach consisting of microalgae cultivation on centrate wastewater, microalgae harvest through flocculation, solar drying of biomass, pyrolysis of biomass to bio-oil, and utilization of co-products, was analyzed and shown to yield profound positive results in comparison with others. The estimated break even selling price of biofuel ($2.23/gallon) is very close to the acceptable level. The approach would have better overall benefits and the internal rate of return would increase up to 18.7% if three critical components, namely cultivation, harvest, and downstream conversion could achieve breakthroughs.