Co-benefit analysis on dioxins and mercury reductions：A case study of the energy policy

• Main Authors: Yi-Hsuan Shih, 施怡瑄
• Other Authors: 曾昭衡
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/k6844j

博士 === 國立臺北科技大學 === 工程科技研究所 === 103 === Various studies have implemented the co-benefit analysis to integrate the health benefits of reductions in criteria air pollutants (CAPs) and the avoided social cost of carbon by reducing greenhouse gases (GHGs) emissions. However, benefits of reductions in hazardous air pollutants (HAPs) are hardly quantified. Therefore, considering that the HAPs would potentially cause more damage (e.g., carcinogen, teratogen, or neurodevelopment retardant) on human health, this study focuses on examining the impacts of Dioxins and mercury to evaluate the health risks posed by the emissions and consequential social costs or externalities. Taking Taiwan’s Sustainable Energy Policy Guideline for example, the emission reductions from both clean energy development and energy saving were assessed to establish a more comprehensive Air Resource Co-Benefits (ARCoB) model. By comparing the observed data with the modeled estimates from five different fugaciy models—CalTOX, Level II, Level III, RAIDAR Level II, and RAIDAR Level III—with the reported PCDD/F emission data in Taiwan, it is considered that the modeled results from CalTOX ver. 4.0 on prediction of both Dioxin concentrations in exposure media and exposure dose of Dioxin were most probable, and thus CalTOX is deemed a suitable tool for health risk assessment for Dioxin emissins in Taiwan. Maximum lifetime excess cancers of 362 to 1,755 cases, caused by elevated cancer risks of 1.6 x 10-5 to 7.6 x 10-5 related to dietary exposure due to anthropogenic Dioxin emissions were determined. Estimated health costs per unit dioxin emissions, including cancer medical costs and cancer mortality costs, were totaled NT$6185,777,529/g I-TEQ. Characteristics of the totaling 30 major anthropogenic mercury emission sources in the North Air Basin were investigated. Incremental mercury depositions on land and offshore of 12.9 μg/m2/yr及2.1 μg/m2/yr were simulated using the AERMOD. By comparing the simulated deposions with the estimated total depositions based on observations, proportions of mercury depositions on land and offshore attributable to local anthropogenic sources were approximated 22% and 24%, respectively. Estimated health costs per unit mercury emissions, including intelligence quotient (IQ) losses and adult mortality costs, totaled NT$141,083,937/kg. Social costs of air pollutants emitted by coal-fired electricity generation were estimated to be the highest of NT$5.54/kWh, followed by NT$1.59/kWh of renewable energies (REs) of biomass and waste energy. Onshore and offshore wind energies were estimated to impose the lowest social costs of NT$0.23/kWh and NT$0.31/kWh, followed by run-of-the-river hydroelectricity’s NT$0.38/kWh, representing theses REs cause least environmental impacts. Estimated social costs of natural gas (NG) electricity is NT$0.51/kWh, of which costs of GHGs emissions takes 69%. An Electricity Dynamic Pricing model was developed to determine the simultaneous effects of REs promotion and energy efficiency improvements (EEIs) in residential, commercial and industrial sectors on enegy costs. The simulation results implied the positive feedback of electricity prices rised by REs promotion will increase the amount of EEIs by 24%, assuming that the increasing electricity bills would encourage the publics to implement more EEIs. Compared with the life-cycle emission factors of coal-fired, analytical results indicate that the health benefits of CAPs reductions take 75%–85% of co-benefits, followed by 8%–18% of GHGs and 5%–7% of HAPs, of which co-benefits of NT$0.27/kWh related to mercury reductions are larger than NT$0.01/kWh related to Dioxin reductions. From cost-benefit analysis, NG’s benefit-cost ratio of 1.6 was revealed to be the highest, followed by REs’ 1.2 and EEIs’ 0.8 (NG &;gt; REs &;gt; EEIs).