The deepening of China’s regional economic integration has posed potential impacts on climate change mitigation. This paper evaluates the impact of Changsha-Zhuzhou-Xiangtan economic integration policy on carbon emissions based on the total industrial output value, analyzes the correlation between carbon emission and total industrial output value of Changsha-Zhuzhou-Xiangtan urban agglomeration from 2000 to 2014, and calculates the carbon dioxide emission per unit of industrial added value. The results show that under the influence of economic integration, the carbon dioxide emission per unit industrial added value of Changsha-Zhuzhou-Xiangtan urban agglomeration decreases significantly, and low-carbon industry gradually occupies a dominant position. The results are helpful for the design of carbon emission reduction path and the formulation of carbon neutralization long-term policy of Changsha-Zhuzhou-Xiangtan urban agglomeration.
With high population density and intensive energy consumption, Beijing has long been facing the huge challenge of ecological security in context of coordinated development of environment and economy. Combining statistical and grid data, this paper analyzed the ecological security status in Beijing from three scales, i.e., city, sub-city and grid, based on an emergetic ecological footprint model. The emergetic ecological footprint (EEF), emergetic ecological carrying capacity (EEC), emergetic ecological deficit (EED) and emergetic ecological pressure index (EEPI) were used to evaluate the ecological security status of Beijing from different scales. Results show that Beijing has been in the state of ecological deficit from 2005 to 2017, and the multi-year average value of ecological pressure is 9.18 with great differences in the spatial distribution of ecological security. Concrete measures are then suggested to promote the ecological security of Beijing.
The enormous interfacial thermal resistance between adjacent CNT leads to a significant weakening of the overall thermal conductivity of the CNT-assembled materials. In this study, based on the parallel CNT interfaces of natural van der Waals interaction, a unique scheme was proposed to enhance the interfacial thermal transport properties. The initial arrangement of polyethylene (PE) chains with linear configuration was oriental controlled and loaded to both sides of parallel CNT interfaces. The results show that the arrangement angle between PE and CNT axis has a key influence on the interfacial thermal conductance, which is conducive to the increase of effective heat transfer area between parallel CNT interfaces, and an abundant low-frequency phonon vibration mode is excited at the interfaces, so as to achieve the significant improvement of the thermal transport properties between parallel CNT interfaces (up to 120%).
In this study, we construct a new climate change policy uncertainty based on the newspaper data for four major countries (China, India, USA and UK). We show some common features of the CPU index. The CPU index of the four countries are highly correlated. And the CPU may fluctuate with economic policy uncertainty and have counter-cyclical characteristics. Our findings can provide some insights for understanding climate policy.
Environmental regulation is a critical instrument for achieving sustainable economic and social development. The iron and steel industry is highly polluting and energy-consuming, posing a significant threat to China’s environmental sustainability. Based on the panel of Chinese provincial-level data from 2000 to 2017, this paper empirically examines how environmental regulation affects the iron and steel industry’s green development. The findings show that there is a U-shaped relationship between environmental regulation and energy-environmental performance. Low environmental regulation intensity inhibits the improvement of energy-environmental performance. But as the regulation intensity increases, it contributes to the advancement of energy-environmental performance. Environmental regulation affects the industrial energy-environment performance through technological innovation, and the relationship between environmental regulation and technological innovation presents a U-shaped relationship. There are noticeable regional differences in the impact of environmental regulation on energy-environmental performance. The findings provide new evidence to confirm the Porter Hypothesis. Finally, this paper provides policy suggestions for further energy-environmental performance improvements in China’s iron and steel industry.
Photovoltaic thermal collectors (PVT) can generate electricity and heat from one module. In a typical aerothermal PVT system, the air flow behind the PV modules is created using air channels, and the heated air is ducted to the point of usage. The central aim of this paper is to simulate a system where the recovered heat from a PV installation is utilized in the energy system of a multifamily building cluster in Sweden. The paper tends to establish if the additional cost of “heat recovery system” components justify the savings obtained due to recovered heat from PV. To achieve this, a simulation model is built in TRNSYS for a multi-family building cluster in Sweden. Specifically, two energy system configurations are simulated.
1) Recovered heat from PV collectors is used for pre-heating of domestic hot water.
2) Heat from PV collectors is used at the evaporator of an air source heat pump to increase its performance. The heat pump is further used to generate domestic hot water.
Results show that the advantage of PVT integration is more pronounced when recovered heat is used directly for pre-heating of DHW. The savings are lower when PVT is coupled with heat pump.
This study develops simulation models and novel energy management strategies of hybrid renewable energy systems integrated with energy storage of pumped hydro and hydrogen taxis for a net-zero energy commercial building sector in Hong Kong. A new time-of-use system management strategy considering the future high penetration of renewable energy installations is proposed based on the estimated local solar photovoltaic and offshore wind power potentials. The research results indicate that it is feasible to develop local hybrid renewable energy systems integrated with pumped hydro and hydrogen vehicle storages for achieving net-zero energy commercial building sectors in high-density regions. The time-of-use operations on the hybrid renewable energy and storage systems significantly reduce the annual electricity bill and equivalent carbon emissions of the net-zero energy commercial building sector. And the future time-of-use management considering renewable energy generations in determining on-peak and off-peak periods improves the renewable energy self-consumption, on-site load coverage and annual electricity bill of the net-zero energy commercial building sector compared with the current time-of-use operation. This study exploring the technical, economic and environmental feasibilities of developing hybrid renewable energy and storage systems for a net-zero energy commercial building sector provides significant guidance for policy makers to develop renewable energy for achieving carbon neutrality in commercial building sectors in urban regions.
It is an effective way to expand the scale of renewable energy utilization by combining energy storage technology with renewable energy. In this paper, a novel energy storage technology based on liquid carbon dioxide storage, low pressure storage and latent cold energy storage is proposed. The main work of this paper is to establish the thermodynamic model of the system, and investigate the influence of key parameters on the performance of the system through parameter analysis. The analysis results show that in a certain range, there are optimal R4419, R129, R2118 and R3836 respectively to make round trip efficiency reach the maximum value. Increasing R129 and R2118 can improve the energy density of the system.
The rapid growth of energy consumption in commercial building operations hinders the pace of carbon emission reduction in China’s building sector, thus bringing great challenges to the successful realization of low-carbon development in China. This study uses historical data on carbon emissions from China’s commercial building operation to establish the STIRPAT model. The model parameters are estimated by LASSO regression, and the Grey Wolf Optimizer (GWO) is used to optimize the nonlinear coefficients of the LASSO regression model. The proposed model is used to evaluate historical carbon emission reduction levels and estimate the peak value of future carbon emissions in China. Findings show that: (1) The main driver forces of carbon dioxide emissions from the commercial building sector in China are population size, GDP per capita, and energy intensity of carbon emissions, and their elastic coefficients are 0.5097, 0.2870, and 0.2006, respectively. (2) The peak emissions of the commercial building sector are 1269.42 MtCO2, and the peak year is estimated to be 2029. Overall, this study analyzes the historical emission reduction levels and prospective peaks of carbon emissions in China’s commercial building sector from a new perspective. The research results can help governments and decision-makers formulate effective emission reduction policies and can also provide references for the low-carbon development of other countries and cities.
Building sector plays an important role in carbon neutral transition, and commercial buildings become key starting point in the building decarbonization. Taking China and the United States (US) as cases, this study is the first to assess carbon-dioxide (CO2) mitigation in commercial building operations at different emission scales and investigate the carbon mitigation efficiency of the two countries in the past decades. The results show that: (1) Economic efficiency and energy intensity are key to reduce CO2 emission intensity in commercial buildings in China and the US, respectively; (2) CO2 mitigation efficiency in China was around 1.5 times that in the US, though CO2 mitigation in China and the US was close; (3) the paths for energy efficiency improvement in commercial buildings in China and the US were mapped to explore the strategy that best decarbonizes buildings operation in the future. Overall, the evaluation model of CO2 mitigation proposed in this study is able to be a guidance for other economies or regions to measure the effect of historical carbon mitigation in building operation.