• Energy Research
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Small-scale bio-energy projects have been launched in rural areas of China and are considered as alternatives to fossil-fuel energy. However, energetic and environmental evaluation of these projects has rarely been carried out, though it is necessary for their long-term development. A village-level biomass gasification project provides an example. A hybrid life-cycle assessment (LCA) of its total nonrenewable energy (NE) cost and associated greenhouse gas (GHG) emissions is presented in this paper. The results show that the total energy cost for one joule of biomass gas output from the project is 2.93 J, of which 0.89 J is from nonrenewable energy, and the related GHG emission cost is 1.17 × 10−4 g CO2-eq over its designed life cycle of 20 years. To provide equivalent effective calorific value for cooking work, the utilization of one joule of biomass gas will lead to more life cycle NE cost by 0.07 J and more GHG emissions by 8.92 × 10−5 g CO2-eq compared to natural gas taking into consideration of the difference in combustion efficiency and calorific value. The small-scale bio-energy project has fallen into dilemma, i.e., struggling for survival, and for a more successful future development of village-level gasification projects, much effort is needed to tide over the plight of its development, such as high cost and low efficiency caused by decentralized construction, technical shortcomings and low utilization rate of by-products.

In this study, our aim was to explore the potential energy savings obtainable from the recycling of 1 tonne of Construction and Demolition Waste (C&DW) generated in the Metropolitan City of Naples. The main fraction composing the functional unit are mixed C&DW, soil and stones, concrete, iron, steel and aluminium. The results evidence that the recycling option for the C&DW is better than landfilling as well as that the production of recycled aggregates is environmentally sustainable since the induced energy and environmental impacts are lower than the avoided energy and environmental impacts in the life cycle of recycled aggregates. This LCA study shows that the transition to the Circular Economy offers many opportunities for improving the energy and environmental performances of the construction sector in the life cycle of construction materials by means of internal recycling strategies (recycling C&DW into recycled aggregates, recycled steel, iron and aluminum) as well as external recycling by using input of other sectors (agri-food by-products) for the manufacturing of construction materials. In this way, the C&D sector also contributes to realizing the energy and bioeconomy transition by disentangling itself from fossil fuel dependence.

The development of the economy, energy conservation and environmental protection should all have similar importance within China's Five-Year Plans, and be implemented in parallel and in interaction with each other. In practice however it is debatable whether they are implemented in a harmonious way. In this case study, which takes place in the city of Urumqi, we identify the elements within the 11th and 12th Five-Year Plans pertaining to economic policy, energy policy and environmental policy, i.e. the 3E policies, and discuss their respective and collective impacts on energy conservation and CO2 and air pollutants reduction. A bottom-up simulation model is built based on the Long Range Energy Alternatives Planning System (LEAP) to simulate the effects of these policies. It is shown that the excessive pursuit of economic growth during the 11th Five Year Plan led to mounting energy consumption and pollutant emissions, and environmental policy only had an obvious effect on the desulfurization of the power industry. On the other hand, during the 12th Five-Year Plan period, the structural adjustment promoted by the economic policy enhanced energy conservation and reduced emissions of pollutants. Energy policy played an important role in the reduction of air pollutants. Moreover environmental policy was strengthened because binding targets on total emissions were set for more pollutants, but there were slightly increased CO2 emissions due to employing more end-of-pipe measures of emission reduction.

Abstract The deeply decarbonized energy economy would be achieved by the efficient power generation and low-carbon end-use equipment and infrastructure, which relies on the fixed cost investments in these items. In this study, we calculated the societal costs by the incremental energy system costs, which are defined the cost of producing, distributing, and consuming energy in a decarbonized energy system. We assess the transformation of the energy system including the major changes in energy supply and end use technology and infrastructure and its related energy costs. The investments in the highly efficient end use of energy, decarbonization of electricity and other fuels including biomass, petroleum, coal, natural gas and switching of end uses to electricity and other low-carbon supplies are calculated. The primary results show that the reference case shows a modest 15% increase in total final energy use, a 9% increase in CO2 emissions relative to 2014 levels, while the deep decarbonization case shows a 20% decrease in total final energy use and an 65% reduction in total emissions. The total societal costs, calculated by summing these three categories costs can be used for assessing the expected cost to achieve the target of greenhouse gas emissions reduction, which can provide theory for implications of low-carbon technology and infrastructure changes for the energy economy and policy.

With increased attention paid to the changes of global climate, the impacts on hydrological processes remain poorly understood in specific basins. In this study, we selected Luanhe River Basin, which is an important source of water supply to Beijing and Hebei, as a case study for the analysis of the combined impact of precipitation and temperature change to hydrological components in a semi-arid river basin. This study investigated the change of the blue water flow (BWF), green water flow (GWF), and green water storage (GWS) by employing the SWAT (Soil and Water Assessment Tool) model and stochastic methods in different time scales during 1960 to 2017. The contribution of climate changes to hydrological change were quantified by 16 hypothetical scenarios by recombining climatic data. The results show that the annual daily maximum and minimum temperature (Tmax, Tmin) increased while their differences (DTR) decreased. However, there was no significant trend in annual precipitation and hydrological components. The trend of precipitation has a positive impact to the change of all three hydrological components. Although precipitation contributes more to changes in hydrological components, more attention also needs to be given to the change of DTR, which has positive impact of GWF that contrasts with that of BWF and GWS. Seasonal scale studies of these changes suggested that more attention should be paid to the climate change in spring and winter when the hydrological components were more sensitive to climate change. Our results summarized hydrological components variability under the impact of climate change and demonstrated the importance of analyses at different time scales, which was expected to provide a reference for water resources management in other semi-arid river basins.

Particulate matter (PM) pollution in high emission regions will affect air quality, human health and climate change on both local and regional scales, and thus attract worldwide attention. In this study, a comprehensive study on PM2.5 and its chemical composition were performed in Yuncheng (the most polluted city of Fen-Wei Plain of China) from November 28, 2020 to January 24, 2021. The average concentration of PM2.5 was 87.8 ± 52.0 μg/m3, which were apparently lower than those observed during the same periods of past five years, attributable to the clean air action plan implemented in this region. NO3- and organic carbon (OC) were the dominant particulate components, which on average contributed 22.6% and 16.5% to PM2.5, respectively. The fractions of NO3-, NH4+, OC and trace metals increased while those of crustal materials and elemental carbon decreased with the degradation of PM2.5 pollution. Six types of PM2.5 sources were identified by the PMF model, including secondary inorganic aerosol (35.3%), coal combustion (28.7%), vehicular emission (20.7%), electroplating industry (8.6%), smelt industry (3.9%) and dust (2.8%). Locations of each identified source were pinpointed based on conditional probability function, potential source contribution function and concentration weighted trajectory, which showed that the geographical distribution of the sources of PM2.5 roughly agreed with the areas of high emission. Overall, this study provides valuable information on atmospheric pollution and deems beneficial for policymakers to take informed action to sustainably improve air quality in highly polluted region.

Abstract Motor vehicle emissions contribute significantly to air pollution in Beijing. Therefore, a number of measures have been taken to control emissions from motor vehicles, including the elimination of high-polluting old vehicles and driving restrictions. We compared the pollution reduction effects and implementation costs of these two policies. The results showed that an average annual investment of about 1.7 billion RMB was invested in a policy of eliminating old vehicles in Beijing, resulting in annual emissions reductions of about 22,600 tons of CO, 1330.2 tons of NOx, 2197 tons of HC, 78.6 tons of PM2.5, and 81.3 tons of PM10. Meanwhile, a driving restrictions policy resulted in an annual loss by consumers of more than 17.84 billion RMB and annual emissions reductions of just 12,000 tons of CO, 845 tons of NOx, 1356 tons of hydrocarbons HC, 53 tons of PM2.5, and 57 tons of PM10. A policy of eliminating old cars is more cost-effective than a driving restrictions policy, policy formulation should take into account the cost-effectiveness of policies.

Starting with the 11th Five-Year Plan (FYP) and continuing in the 12th FYP, quantitative and binding targets have been set for energy-efficiency improvement in China. Drawing on international experience in burden-sharing on climate change, this paper presents a framework for provincial-level disaggregation of energy-saving targets in China. Based on principles of equity and efficiency, four scenarios have been established by weighting different choice preferences of responsibility, capacity, and potential. In addition, nonlinear and linear allocation models have been developed by considering or ignoring marginal energy-saving cost. When this framework was applied to the disaggregation of the national energy saving target of 16% during the 12th FYP, the results show that the final allocation schemes are largely determined by the policy maker's choice preferences. The extreme reduction target of 37.26% fell to Shanghai under responsibility preferring (RP) using the linear allocation method, while the capability preferring (CP) scenario considering marginal energy-saving cost is the closest to the actual scheme accepted by the 30 provinces. Development of such a framework may serve as a feasible policy instrument to help China achieve its conservation targets in a cost-effective way and in accordance with its regional development strategies.