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Flue gas desulfurization (FGD) and selective catalytic reduction (SCR) technologies have been widely used to control the emissions of sulphur dioxide (SO2) and nitrogen oxides (NOX) from coal-fired power plants (CFPPs). Field measurements of emission characteristics of four conventional CFPPs indicated a significant increase in particulate ionic species, increasing PM2.5 emission with FGD and SCR installations. The mean concentrations of PM2.5 from all CFPPs tested were 3.79 ± 1.37 mg/m3 and 5.02 ± 1.73 mg/m3 at the FGD inlet and outlet, respectively, and the corresponding contributions of ionic species were 19.1 ± 7.7% and 38.2 ± 7.8%, respectively. The FGD was found to enhance the conversion of NH3 slip from the SCR to NH4+ in the PM2.5, together with the conversion of SO2 to SO42-, and increased the primary NH4+ and SO42- aerosol emissions by approximately 18.9 and 4.2 times, respectively. This adverse effect should be considered when updating the emission inventory of CFPPs and should draw the attention of policy-makers for future air pollution control.

Abstract Compared with other traditional energy sources, renewable energy, which results the less pollution and has numerous resources, is a significant factor in addressing the current issues of the serious environmental pollution and the resource depletion. Large-scale renewable energy integrated to the grid could bring change in both morphological structure and operation modes of energy transmission. Therefore, it is necessary to research the evolution mechanism of the future transmission network with a high proportion of the renewable energy. In this paper, an evolution framework of power system with high proportion of renewable energy is proposed. Firstly, a network equivalence and simplification based on power transfer distribution factors (PTDFs) is proposed, which can effectively simplify the decision-making process of evolution of large-scale power system. Then, an annual production simulation (8760 h) which takes into account renewable energy and load fluctuations is used to find out the bottleneck of the power grid. Based on the above methods, evolution strategy of power system with high proportion of renewable energy is studied for finding out optimal expansion strategy. A real power system of Zhejiang province is used as a test system. Test results demonstrate the feasibility of the proposed evolution framework.

Abstract China has the advantage of learning from the mistakes made by nations that have developed their nuclear power energy system in the last century. Such mistakes encompass the lack of sustainable development of the nuclear energy and poor planning in the back-end of the nuclear fuel cycle. The present paper studies the evolution of a double strata cycle with fast reactor gradually replacing the LWR. It starts from 2035 and covers the historical development of nuclear energy in China to the year 2100. The paper studies the ADS impact on the NFC and estimates the number and the deploying schedule of the ADS reactors to limit the accumulation of minor actinides. The other aspects considered here are natural uranium resources, fuel utilization efficiency, proliferation and diversion risks, spent fuel production and overall materials flow. Additionally, perturbation calculations were performed to evaluate the impact of the uncertainty on key parameters. The results are discussed in view of the Chinese nuclear fuel cycle plan and their policy implications are thoroughly evaluated.

Abstract The industrial exhaust flue gas contains tremendous waste heat that cannot be efficiently recovered by conventional condensing heat exchanger. This paper proposes a novel full-open absorption heat pump for the total heat recovery of flue gas. The recovered heat is used for district heating. By applying direct-contact heat and mass transfer without solid transfer interfaces, the novel system can save considerable metallic tube or plate materials and therefore the initial investment can be reduced substantially. A prototype full-open absorption heat pump is developed and tested, achieving the COP (coefficient of performance) of 1.621 and the exit flue gas dew point of 36.2 °C at most. A detailed theoretical model in Eulerian–Lagrangian formulation is established, involving in conjugate heat and mass transfer and particle dynamics. The numerical simulation agrees well with the experiment results. On the basis of the validated model, three critical parameters, including excess air coefficient of the burner, moisture content of the objective flue gas and return water temperature of the district heating network, are selected to study their effects on system performances. As a controlled variable, especially, the excess air coefficient plays an important role by influencing the regeneration of the liquid absorbent in the generator. The full-open absorption heat pump outperforms the condensing heat exchanger by 19.7–178.1% in heat recovery capacity as the return water temperature increases from 40 to 55 °C.

According to the U.S. Department of Energy, about 40% of total energy is consumed on buildings in industrialized countries, among which 68% is electricity. Recently research shows that 20%∼30% of building energy consumption can be saved with optimized operation and management without changing building structure and hardware configuration of energy supply system significantly. Therefore, there is a huge potential for building energy savings through efficient operation.

Abstract Identifying the appropriate amount of subsidy is crucial to spur the development of low carbon electricity technologies such as wind power that are currently not competitive with conventional coal-fired power on the basis of levelized cost. Though essential for formulating subsidy policy, most of the existing planning tools have not been tailored for policymakers, especially at the sub-national level. In this paper, we introduce an integrated renewable power planning (IRPP) model that is both practical and flexible. This model integrates resource databases, equipment databases and levelized cost calculation module to generate supply curves for wind and solar and evaluate potential subsidy to achieve a certain installation target. A case study focused on wind power planning in Fujian Province is performed. Under the wind power feed-in-tariff of 0.61 yuan/kWh, the generation can reach about 3.7 TWh, and total subsidy will be about 260 million yuan (including subsidies already paid to existing projects). Sensitivity analysis shows that this number will significantly increase if capital cost of wind is reduced or external cost of coal-fired power is internalized.

Abstract Air source heat pumps (ASHPs) are widely used in various types of buildings in different regions of China. Considering the significant differences in the characteristics in heat source side and user side, providing different products for different zones is an effective strategy to promote the systematic development of the ASHP technology. To realize the goal of energy conservation, standard rating conditions are extremely important. The principles for determining the standard rating conditions based on a two-side (heat source/user side) multi-grade (different conditions) method were proposed along with the development of related standards. Therefore, the establishment of standard rating condition is introduced and summarized systematically. For heat source side, the standard rating conditions for heating were classified into four types according to the lowest ambient temperature (−25, −12, −2, 7 °C), while for cooling they were constant (35 °C). For user side, the conditions for supply air (20/27 °C for heating/ cooling), floor heating (35 °C), radiator (50 °C), fan coil unit (41/7 °C for heating/cooling), domestic hot water (55 °C), and industrial use were also determined. This study introduced the implications on ASHP by different standard rating conditions, especially the technical requirements, which indicated the necessity of providing different system cycles and compressors. The energy savings and economic benefits were also evaluated. The primary energy saving rate reached 15.3% and 41.6% compared with coal heating and conventional ASHP respectively by using low ambient temperature ASHP. The results showed that these standards have been satisfactorily developed.

The DC distribution system is an important development direction of the distribution system, which can improve the reliability and the quality of the power supply, and support the new energy, the energy storage, the electric vehicles, and the flexible access of AC and DC loads to grid. To realize the demonstration application of the DC distribution technology, China’s first demonstration project of the medium voltage DC distribution network will be built in Zhuhai, Guangdong Province to support the construction of the city energy internet. First, this paper analyzes the demand of the DC distribution network project, and puts forward the construction content and construction target. Then, it designs and analyzes the electrical connection mode, system operation mode, and startup and shutdown mode of the DC distribution network, and proposes the overall project construction plan. Finally, it conducts the specific project design and analysis, which mainly include the selection of equipment such as inverters, DC transformers and DC circuit breakers, the design and analysis of the DC control and protection system, the design and analysis of the over-voltage protection and the configuration scheme of the lightning arrester, and analysis of the system transient characteristics. The design and analysis of the engineering program is a combination of China’s distribution network engineering practice and technical characteristics, which lays a solid foundation for the advancement of the DC power distribution technology in China, and has reference value and demonstration effect for the design and construction of other projects.