• Energy Research
• 7. Clean energy close
• 1. No poverty close
• Chinese Academy of Sciences close

Abstract Methane is responsible for 20% of the global warming resulting from greenhouse gas emissions. Municipal solid waste (MSW) landfills are the third largest anthropogenic source of methane and are thus important to estimating the global methane budget and evaluating its contribution to global greenhouse gas emissions. Based on the greenhouse gas inventory guidelines from the Intergovernmental Panel on Climate Change (IPCC) and the first-order decay method used to estimate emissions from MSW landfills – and in line with MSW management in various regions – we calculated methane emissions from MSW landfills in various Chinese provinces from 2003 to 2013. During this period, methane emissions from MSW landfills increased from 1141.10 Gg to 1858.98 Gg, representing a mean annual increase of 71.79 Gg. MSW emissions tended to increase more in the northern and western provinces than in the southern and eastern provinces, as methane emissions strongly and positively correlated with population and socioeconomic demographics. MSW decontamination is growing rapidly in China, and landfills predominate in all MSW treatments; moreover, incineration has also dramatically increased in recent years.

The demand for sustainable functional materials with an eco-friendly preparation process is on the rise. Lignocellulosics has been attributed as the most sustainable bioresource on earth which can meet the stringent requirements of functionalization. However, cellulose nanomaterials obtained from lignocellulosics which has reached advanced stages as a sustainable functional material is challenged by its preparation procedures. These procedures can not best be described as sustainable and eco-friendly owning to lots of energy and chemicals spent in the pre-treatment and purification processes. These processes are intended to aid fractionation into the major components in order to remove lignin and hemicellulose for the production of cellulose nanomaterials. This work is thus centred on reviewing the progress achieved in introducing a new cellulose nanomaterial containing lignin. The preparation processes, properties and applications of this new lignin-containing cellulose nanomaterial will be discussed in order to chart a sustainable preparation route for cellulose nanomaterials.

AbstractA ternary Pt/Au/TiO2 nanoparticle (NP) decorated plasmonic wood carbon has been successfully fabricated by a simple two‐step calcination method. The as‐prepared Pt/Au/TiO2 NP‐decorated wood carbon showed an interfacial solar steam generation efficiency up to 90.4 %. Furthermore, the floating system exhibits an excellent photodegradation of tetracycline (TC; 40 mg L−1). Up to 94 % degradation was achieved after 80 min of continuous light irradiation (λ>420 nm) with the assistance of solar steam process. The photocatalysis is promoted by the introduction of Pt/Au nanocomponents, which suppress the recombination of electron–hole pairs generated on TiO2 and facilitate electron transfer. High‐performance liquid chromatography mass spectrometry was employed to identify the reaction products of the photocatalytic system and a mechanistic insight was also provided. The as‐prepared three‐dimensional plasmonic wood carbon has a high photocatalytic performance. Such wood carbon‐based system is recyclable and scalable for practical and versatile solar‐driven clean water generation.

With concerns of energy shortages, China, like the United States, European Union, and other countries, is promoting the development of biofuels. However, China also faces high future demand for food and feed, and so its bioenergy program must try to strike a balance between food and fuel. The goals of this paper are to provide an overview of China's current bioethanol program, identify the potential for using marginal lands for feedstock production, and measure the likely impacts of China's bioethanol development on the nation's future food self-sufficiency. Our results indicate that the potential to use marginal land for bioethanol feedstock production is limited. Applying a modeling approach based on highly disaggregated data by region, our analysis shows that the target of 10 million t of bioethanol by 2020 seems to be a prudent target, causing no major disturbances in China's food security. But the expansion of bioethanol may increase environmental pressures due to the higher levels of fertilizer use. This study shows also that if China were able to cultivate 45% of its required bioethanol feedstock on new marginal land, it would further limit negative effects of the bioethanol program on the domestic and international economy, but at the expense of having to apply another 750 thousand t of fertilizer.

Abstract The mechanism of precipitation for substances produced by the reductive decomposition of a nonaqueous electrolyte solution (NES) at a graphite electrode (GE) was investigated with the help of classical thermodynamics in this paper. It was found that the substances tend to precipitate from a supersaturated NES by overcoming a Gibbs free energy barrier. This requires the atoms or molecules of the substances to initially aggregate into a stable solid nucleus, which will grow continuously into a macroscopic solid particle subsequently. When the Gibbs free energy barrier is reduced to zero under a certain condition, the substances will precipitate from the supersaturated NES as a two-dimensional (2D) solid layer on the GE surface in a nucleationless manner. Moreover, when the sum of the substance–NES interaction and the substance–GE interaction is stronger than the GE–NES interaction, the substances will even precipitate from an unsaturated NES as a 2D solid layer on the GE surface, provided the unsaturation potential is not too high.

A small-scale combined cooling and power (CCP) system usually serves district air conditioning apart from power generation purposes. The typical system consists of a gas turbine and an exhaust gas-fired absorption refrigerator. The surplus heat of the gas turbine is recovered to generate cooling energy. In this way, the CCP system has a high overall efficiency at the design point. However, the CCP system usually runs under off-design conditions because the users’ demand varies frequently. The operating strategy of the gas turbine will affect the thermodynamic performance of itself and the entire CCP system. The operating strategies for gas turbines include the reducing turbine inlet temperature (TIT) and the compressor inlet air throttling (IAT). A CCP system, consisting of an OPRA gas turbine and a double effects absorption refrigerator, is investigated to identify the effects of different operating strategies. The CCP system is simulated based on the partial-load model of gas turbine and absorption refrigerator. The off-design performance of the CCP system is compared under different operating strategies. The results show that the IAT strategy is the better one. At 50% rated power output of the gas turbine, the IAT operating strategy can increase overall system efficiency by 10% compared with the TIT strategy. In general, the IAT operating strategy is suited for other gas turbines. However, the benefits of IAT should be investigated in the future, when different gas turbine is adopted. This study may provide a new operating strategy of small scale gas turbine to improve the off-design performance of CCP system.

In this analysis, the Aqua/MODIS aerosol optical thickness (AOD), Aura/OMI tropospheric NO2 and SO2 column concentration from 2006 to 2015 were used to statistically analyze the spatial distribution characteristics and variation trends of three polluted parameters from three temporal scales of monthly, seasonal and annual average. The results showed that the minimum values of NO2 and SO2 column concentrations both appeared in July and August, and the maximum values appeared in December and January, which was contrary to the variations in AOD. The highly polluted levels were mainly distributed in Shijiazhuang, Xingtai, and Yancheng cities of Hebei Province, and gradually transported to Zhengzhou, Henan Province, north and southwest of Shandong Province, and Tianjin, along the main line of Taiyuan-Linyi, Shanxi Province. AOD and NO2 had significant differences on the seasonal average scale, whereas SO2 had little changes. These pollutants had declined year by year since 2011, in the 10-year period, AOD and SO2 respectively decreased by 17.14% and 10.57%, and only NO2 rose from 8.69 × 1015 molecules/cm2 in 2006 to 9.10 × 1015 molecules/cm2 in 2015 with the increase rate of 4.79%. Integrated with MODIS-released fire products and the Multi-resolution Emission Inventory for China (MEIC), high AOD values in summer were usually accompanied by frequent biomass burning, and heavy heating demand of coal burning led to largest NO2 and SO2 levels in winter. Both inter-annual variations of MEIC NOx and OMI-observed NO2 responded to emission reductions of vehicle exhaustions positively, but vehicle population in Henan and Shandong provinces need to be further controlled. The significant decline of SO2 is mainly attributed to the enforcement of de-sulfurization devices in power plants. Our study found that in the treatment of complex atmospheric pollution, in addition to strict control of common sources of emissions from AOD, NO2 and SO2, it is also necessary to consider their individual characteristics.

AbstractThe South China, especially Guangdong Province, as the most developed area of China emitted large CO2 from energy consumption and industrial production, actively advocates low-carbon development strategies. As an effective option to reduce CO2 emissions, CCS is potentially an effective option to reduce CO2 emissions to low-carbon economy development of South China, especially to Guangdong province. The CO2 storage potential in sedimentary basins onshore South China is limited as previous indicated. So the potential of sub-seafloor CO2 storage in offshore basins would be important. According to the assessment in this paper, large sedimentary basins offshore in the northern SCS have huge CO2 storage potential. Miocene deltaic, coastal plain, and neritic clastic rocks in these basins contain high-porosity and high-permeability aquifers and excellent seals. The estimated effective storage capacity, which is 2.6% of the theoretical capacity, is ∼300 GtCO2 in PRMB, ∼57 GtCO2 in BBGB, ∼41Gt CO2 in QDNB and∼160Gt CO2 in YGHB. On the whole, the Tertiary sedimentary basins in northern SCS margin have large storage capacities of abut 567Gt CO2, which provide a promising storage option for CCS implementation in South China. As the high costs is a major obstacles for sub-seafloor CO2 storage, the reuse of infrastructures for oil and gas development, such as platforms, wells and pipelines, would be the first choice. Although the theoretical storage capacities of the offshore oil and gas fields in the northern SCS are small, they distributed as groups and clusters and associated with sufficient quantified CO2 storage capacity in the saline aquifers. Further assessments are needed to define the residual life (= equipment life minus the field life) of the infrastructures, their practical and matched storage capacities, as well as a proper character and site screening particularly in regard to containment and risk of leakage. All these have been done well ahead of the real abandons of the oil/gas fields, so that the fields are in “CO2 Storage Readlines (CSR)”.