| Coal combustion in electricity generating units is one of the major sources, worldwide and in China, of atmospheric mercury(Hg) pollution, which contaminates the environment, enters the food chain and has devastating impacts on human health. A recent new international treaty, called the “Minamata Convention on Mercury” recognizes the importance of mercury and its compounds as toxics and aims to control and, where feasible, reduce, its releases and emissions, including from coal-fired power plants. That is why in China and other regions of the world policymakers are gearing up their legislation frameworks to step up efforts to control mercury emissions from this sector.This study developed a cost-effectiveness analysis tool for mercury emission control technologies, co-benefit and dedicated, for coal-fired power plants in China, at the enterprise level and the sector level. A key feature of the analysis is the use of a pollutant equivalent method to apportion costs of co-benefit technologies to mercury control only. This shows that less than 15% of costs of co-benefit control technologies are attributed to mercury abatement. Our research demonstrates that a fabric filter installed upstream of a wet flue gas desulfurization system(FF+WFGD) is the most cost-effective co-benefit control technology combination for a 600 MW power plant, which is expected to become the most popular size in the Chinese power sector. The costs attributed to mercury control of FF+WFGD are estimated at 8,696 CNY/kg Hg removed. Halogen injection(HI), applied upstream of selective catalytic reduction(SCR) + electrostatic precipitator(ESP) +WFGD, with costs of 3,657 CNY/kg Hg removed, is a promising cost-effective dedicated approach. Total and incremental costs curves for several mercury control technology options derived within our research are used to substantiate a decision tree which provides a simple yet clear guidance for Chinese power plants operators in choosing the Best Available Techniques(BAT) for different mercury control levels.Four different control scenarios were developed for 2020 and 2030; these include a business as usual(BAU) scenario and three Minamata scenarios simulating different options to comply with requirements of the Minamata Convention. Results show that under BAU scenario, replacement of ESP with more mercury control-effective FF will result in a total mercury removal of 487 tons by 2030, with total annual costs of CNY 10.1 billion apportioned to mercury. The “Minamata Low” scenario assumes that Chinese coal-fired utilities will be encouraged to adopt mercury control measures, including retrofitting ESP with FF, stepping up application rates of SCR, and introducing ACI systems and HI techniques. These measures would allow achieving overall mercury removal efficiency of 85% in 2030, with costs close to CNY 14 billion. The “Minamata Medium” scenario relies on more aggressive deployment of dedicated control technology, with double rates of application of ACI and HI than in the “Minamata Low”. The removal efficiency target achieved with these control measures in 2030 is 90%, similar to the current existing target in the United States(US). However, the associated annual costs, estimated in CNY 15.8 billion(or $2.5 billion) are about one fourth the US costs to comply with the 2011 Mercury Air Toxic Standard(MATS) rule(estimated at $9.6 billion annually). The 2030 “Minamata High” scenario supposes that ACI would be installed on 35% of the power plants, and HI would be practiced on 30% of the national fleet. These measures, costing CNY 16.5 billion annually, would achieve 94% overall mercury removal efficiency(a reduction of 70% compared to 2010).The economic analysis presented in this research yields recommendations to the enterprises and policy makers for increasing demand of atmospheric mercury control. It provides an analytical framework for strategies to be devised by China for the implementation of the Minamata Convention on Mercury. |
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