| With rapid economic growth and accelerated industrialization,China’s energy consumption and the resulting air pollution problems have become increasingly prominent.Coal is the most used fossil fuel energy in China,nearly half of coal was used in thermal power generation in 2018.Combustion of coal produced a large number of air pollutants including SO2 and NOx.To alleviate the negative environmental impact of thermal power plants,it is necessary to install control equipment and other pollution prevention measures.In recent years,as one of the most economically developed regions in China,the Yangtze River Delta(YRD)region is also a demonstration area of coal power transformation.The continuous installation and transformation of control equipment for coal-fired power plants not only improve air quality but also bring some control costs.In this context,quantitative research on the control technologies cost at the unit-level and evaluation of the control costs incurred under higher standard emission standards could provide support for policymakers with basic data of the control costs of coal-fired power plants in the YRD region,and has great significance for the region to formulate control policies and management strategies reasonably.This study first built the control cost of coal-fired power units database and calculated control technology costs of coal-fired power units with different capacities.Secondly,it quantitatively analyzes the temporal and spatial changes of control technology cost of coal-fired power units in cities in the YRD region.Subsequently,this study adopted a unit-level control cost optimization model based on an integer linear programming(ILP)model to estimate the growth of control technology costs under different further emission reduction targets and gave specific end-of-pipe control technology improvement strategies.The main conclusions of this article are as follows:In 2010,2014,and 2018,the fixed costs of desulfurization technologies in the Yangtze River Delta region were 2.03 billion CNY,3.22 billion CNY,and 4.34 billion CNY,respectively.The operating costs were 7.62 billion CNY,9.08 billion CNY,and13.94 billion CNY.The cost of limestone-gypsum wet flue gas desulfurization(LgFGD)accounted for more than 97.0% of the total desulfurization cost.In 2018,large units(≥300MW)accounted for a high proportion of installed desulfurization capacity,while small units(<100MW)accounted for only 8.0% of installed desulfurization capacity,but the fixed cost and operating cost accounted for 22.2% and 11.6% of the total.The desulfurization cost of different capacity units has varied.For Lg-FGD,the desulfurization cost of units with an installed capacity of 50 MW is 4.95 CNY/kg,and the desulfurization cost of units with an installed capacity of 1000 MW is 2.92 CNY/kg.The desulfurization cost of cities in the YRD region is higher in the east and lower in the west.From 2010 to 2018,the desulfurization cost of 33 cities increased,and the annual growth rate of desulfurization cost in some cities reached about 10%.From the perspective of different capacity levels,from 2010 to 2018,the number of cities in which the installation cost of desulfurization equipment for small units exceeded 100 million CNY continued to grow,while the desulfurization cost of small units still maintained an increasing momentum.In 2010,2014,and 2018,the fixed costs of denitrification technologies in the YRD region were 0.27 billion CNY,0.71 billion CNY,and 3.53 billion CNY,respectively,and operating costs were 1.12 billion CNY,2.42 billion CNY,and 7.72 billion CNY,with Selective catalytic reduction(SCR)occupying an absolute dominant position.The installed capacity ratio of small units is 8.0%,and the fixed cost and operating cost of denitrification account for 25.3% and 18.7% of the total respectively.The denitrification cost of different capacity units also has varied.For SCR,the denitrification cost of 50 MW capacity unit is 9.93 CNY/kg,and the denitrification cost of 1000 MW capacity unit is 2.67 CNY/kg.From 2010 to 2018,denitrification costs in cities in the YRD region increased significantly,with higher denitrification costs in coastal cities and lower in inland cities as a whole.Due to the implementation of ultralow emission standards,the increase in denitrification costs was accompanied by the increase in the number of units with denitrification equipment,while the retirement of small units had no obvious impact on costs.From the perspective of different capacity levels,the denitrification costs of small units in Wuxi and Suzhou,which rank among the top five cities in terms of denitrification costs,accounted for 29.8% and 37.6% of the total costs.As the cost of denitrification is greatly affected by the scale of the unit,the problem of installing denitrification equipment with high cost but low efficiency for small units could not be ignored.Finally,the control cost optimization model proposes the following control technology improvement strategies for future higher emission reduction targets: For the desulfurization control target,due to the higher total cost of equipment upgrades for large units,firstly small units could upgrade control technologies with higher efficiency and lower unit installed costs,and secondly medium-capacity units upgrade FGD-U equipment.For the denitrification targets,when most units have installed denitrification equipment,small units could install control equipment with higher removal efficiency technology with a relatively low unit installed cost.After that,due to the large amount of NOx produced by large units and the obvious emission reduction effects brought about by technology upgrades,the technology of ultra-low emission standard denitrification equipment(SCR-U)for large units can be upgraded.The results of this study show the unit emission reduction costs of large units with the same control technology are far lower than those of small units.From an economically efficient point of view,differentiated upgrade strategies should be developed for coal-fired power units of different capacities.Firstly,small units could install control measures with the lower installed capacity cost,to improve emission reduction efficiency with lower costs.For large units that need to upgrade control equipment to meet ultra-low emission standards,appropriate measures can be taken to reduce the economic burden on the power plant.Consider gradually decommissioning small units and replacing them with large units,which can reduce part of the control cost.Finally,the installation of control equipment remains a key means of emission abatement.The government could continue to invest in technology research and industry incubation to improve the efficiency of control technology and reduce the technology cost to meet increasingly stringent emission standards. |
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