Emission sources and mitigation of fluorinated Non‐CO2 greenhouse gas in registered CDM projects

Typical non‐CO2 greenhouse gases in clean development mechanism (CDM) projects include methane (CH4), nitrous oxide (N2O), and fluorinated gases (F‐gases). The use of F‐gases, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), has increased sharply in the semiconductor and electronics manufacturing industries. The global warming potential of F‐gases is very high, ranging from 140 to 23 900. Therefore, there has been considerable interest in the reduction of F‐gas emissions. This paper examines the emission sources, methodology, and reduction technologies of F‐gases, using the project design documents of CDM projects registered in the United Nations Framework Convention on Climate Change (UNFCCC). In comparison to other non‐CO2 gases, CDM projects have significantly reduced annual F‐gas emissions. CDM projects achieved reductions of HFCs using thermal oxidation technology, mostly involving the chlorodifluoromethane (HCFC‐22) production process; conversely, PFC reductions targeted the aluminum smelting process to reduce the anode effect. The extent of SF6 reduction in CDM projects was relatively high in the liquid crystal display (LCD) manufacturing process using thermal and catalytic oxidation, although SF6 recovery technology was much more effective in terms of capital and annual costs. Overall, large amounts of F‐gases could be alleviated using thermal or catalytic oxidation. However, the economical reduction of F‐gas emissions would be possible using recovery technology. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.