Input–output efficiency model of urban green-energy development from the perspective of a low-carbon economy

With the acceleration of urbanization, cities are the main targets for carbon neutrality and urban energy is the terminal of energy consumption and the integration point of various energy systems. Therefore, there is a need to promote the development of urban green energy and achieve low input and high output to achieve a low-carbon economy in cities. Previous studies have not considered the input–output efficiency of urban green-energy development. This study fills this gap. Based on the economic–energy–environmental framework, an input–output efficiency-evaluation index system for urban green-energy development was constructed. Based on improved data-envelopment analysis, a comparative evaluation of the input–output efficiency of green-energy development was carried out in 30 provinces in China in 2019. Considering the differences in regions, the development of urban green energy in different provinces was classified. From the perspective of a low-carbon economy, economic growth factors and environmental constraint factors were set. Together with the generalized Divisia index approach, the input–output efficiency optimization directions of urban green-energy development were obtained. The results showed that the input–output efficiencies of urban green-energy development in Jiangsu, Zhejiang, Fujian, Inner Mongolia, Ningxia and other provinces and cities were relatively high. Provinces with faster economic development and higher environmental carrying capacity have advantages after optimization and will become pilot areas for the development of urban green energy. This research provides a reference for the development of urban green energy in various provinces from the input and output perspective.

Photosynthetic traits of Australian wild rice (Oryza australiensis) confer tolerance to extreme daytime temperatures

Key message A wild relative of rice from the Australian savannah was compared with cultivated rice, revealing thermotolerance in growth and photosynthetic processes and a more robust carbon economy in extreme heat. Abstract Above ~ 32 °C, impaired photosynthesis compromises the productivity of rice. We compared leaf tissues from heat-tolerant wild rice (Oryza australiensis) with temperate-adapted O. sativa after sustained exposure to heat, as well as diurnal heat shock. Leaf elongation and shoot biomass in O. australiensis were unimpaired at 45 °C, and soluble sugar concentrations trebled during 10 h of a 45 °C shock treatment. By contrast, 45 °C slowed growth strongly in O. sativa. Chloroplastic CO2 concentrations eliminated CO2 supply to chloroplasts as the basis of differential heat tolerance. This directed our attention to carboxylation and the abundance of the heat-sensitive chaperone Rubisco activase (Rca) in each species. Surprisingly, O. australiensis leaves at 45 °C had 50% less Rca per unit Rubisco, even though CO2 assimilation was faster than at 30 °C. By contrast, Rca per unit Rubisco doubled in O. sativa at 45 °C while CO2 assimilation was slower, reflecting its inferior Rca thermostability. Plants grown at 45 °C were simultaneously exposed to 700 ppm CO2 to enhance the CO2 supply to Rubisco. Growth at 45 °C responded to CO2 enrichment in O. australiensis but not O. sativa, reflecting more robust carboxylation capacity and thermal tolerance in the wild rice relative.

Thermodynamic Rarity Assessment of Mobile Phone PCBs: A Physical Criticality Indicator in Times of Shortage

Rising prices in energy, raw materials, and shortages of critical raw materials (CRMs) for renewable energies or electric vehicles are jeopardizing the transition to a low-carbon economy. Therefore, managing scarce resources must be a priority for governments. To that end, appropriate indicators that can identify the criticality of raw materials and products is key. Thermodynamic rarity (TR) is an exergy-based indicator that measures the scarcity of elements in the earth’s crust and the energy intensity to extract and refine them. This paper uses TR to study 70 Mobile Phone (MP) Printed Circuit Boards (PCBs) samples. Results show that an average MP PCB has a TR of 88 MJ per unit, indicating their intensive use of valuable materials. Every year the embedded TR increases by 36,250 GWh worldwide -similar to the electricity consumed by Denmark in 2019- due to annual production of MP. Pd, Ta and Au embedded in MP PCBs worldwide between 2007 and 2021 contribute to 90% of the overall TR, which account for 75, 600 and 250 tones, respectively, and increasing by 11% annually. This, coupled with the short lifespan of MP, makes PCBs an important potential source of secondary resources.

Influence of ambient temperature on the efficiency of underground spot cooling system

In mine air conditioning systems, the vapour compression refrigeration cycle seems to be currently the most widespread method of artificial cooling. In literature some other methods for cooling a mine are also presented, like using free-cooling in refrigeration systems. Mine workings in Jiu Valley are using the primary and secondary ventilation system for cooling the underground. Today the activities are focused mainly on mine closure as a part of transition to the low carbon economy, and this situation brings new challenges regarding the mine ventilation system, which was designed to meet the needs of a full-scale operation. As a result, locally ambient temperatures can rise, and spot cooling systems can be used, in order to cool the air. Such a system has been considered and calculations have been made to evaluate its thermal efficiency at different ambient temperatures.

Lanthanide metal–organic frameworks for the fixation of CO2 under aqueous-rich and mixed-gas conditions

The development of effective catalysts is one of the big challenges associated with a new circular carbon economy addressing climate change.

Environmental and Economic Prerequisites for Russiaʼs Transition to a Low-Carbon Economy

Introduction. Environmental and climatic problems of the Russian Federation have attracted considerable attention from scientists, politicians, as well as the general public. Human activities are a major cause of pollution and global warming, which necessitates the search for a new way of economic development reducing the adverse impact on the environment. The authors consider a low-carbon economy aimed at simultaneously solving economic, environmental, and climatic problems as such a guideline. Based on the research conducted the article identifies the constituent entities of the Russian Federation in which pilot projects for the transition of enterprises and cities to low-carbon development are most expedient to implement. The gained experience should be applied in other regions of the country in the future. Materials and Methods. Data from the Federal State Statistics Service and the Ministry of Natural Resources and Environment of the Russian Federation on 20 most populated constituent entities of the country were analyzed. In order to identify the regions with the largest volumes of various types of pollution, the data ranking method was applied. The authors have also carried out an analysis of relative indicators of natural resource intensity associated with emission into the atmosphere, discharges of polluted wastewater, and production of municipal solid waste. Results. The performed analysis has shown the heterogeneity of the environmental and economic development of the constituent entities of the Russian Federation. It has been concluded that among the regions considered, it is most expedient to implement pilot projects for low-carbon development in cities and in “polluting” industries located in the Kemerovo, Sverdlovsk, and Chelyabinsk Regions, as well as in the Krasnoyarsk Territory. Discussion and Conclusion. The results of the study can be used in the development of environmental programs, as well as in the development of directions for mitigating the environmental impact in the most polluted regions of the country and in industries with high natural resource intensity.