Sulfur hexafluoride (SF6), perfluoromethane (CF4) and perfluoroethane (C2F6) are strong greenhouse gases with long (>1000 year) atmospheric residence times. We derive emission factors for the major anthropogenic sources and project future emissions for 5 regions and the world. Although firms in many industrialized countries are already limiting emissions, without further policy intervention global emissions will rise 150% (CF4 and C2F6) and 210% (SF6) between 1990 and 2050; radiative forcing will increase 0.026 W m-2. Full application of available low-cost and costless policies in industrialized nations would cut that radiative forcing by one-quarter. Increased forcing due to these gases is small (<2%) relative to other gases but permanent on the timescale of human civilization. We also quantify plausible manipulations to governmental data that will be used to determine compliance with the 1997 Kyoto Protocol, which includes commitments for industrialized countries to regulate these and other greenhouse gases. More complete and transparent data are urgently needed. West European nations, for example, can ‘cut’ their emissions of these gases by half by 2010 simply by manipulating emission factors within the current bounds of uncertainty.

A model for estimating future emissions of sulfur hexafluoride and perfluorocarbons

Die ambitionierten Treibhausgas(THG)-Reduktionsziele Deutschlands erfordern politische Anreize, den THG-Ausstos in energieintensiven Industrien zu mindern ohne dabei deren Wettbewerbsfahigkeit zu beeintrachtigen. In der Dissertation wird daher der Einfluss verschiedener klimapolitischer Instrumente (ETS, EEG, EnergieStG, StromStG) auf die induzierten Emissionsminderungen sowie auf relevante okonomische Kenngrosen analysiert, wobei die Metallerzeugung im Fokus der Analysen steht.

/pdf/ein-ansatz-zur-bewertung-klimapolitischer-instrumente-am-42t59dykmp.pdf

Ein Ansatz zur Bewertung klimapolitischer Instrumente am Beispiel der Metallerzeugung und -verarbeitung

Anode processes for Nd electrowinning from LiF-NdF3-Nd2O3 melt

An electroanalytical study of electrode reactions on carbon anodes during electrolytic production of aluminum

The US Environmental Protection Agency (EPA) and the US Aluminum Association sponsored measurements of two perfluorocarbon (PFC) gases: tetrafluoromethane and hexafluoroethane. The measurements at six primary aluminum production facilities provided data on emissions of these compounds during normal aluminum smelting operations. The measurements were made using process mass spectrometry, a technique capable of monitoring the rate of emissions with a time resolution of seconds. The PFC concentration measurements were combined with smelting process data collected during the measurements to provide new insights into the relationships between the process variables and PFC emissions. Detailed data were obtained at several locations relating overall cell voltage and PFC emission rates. The profiles of PFC emissions and voltage at a time resolution of seconds provide valuable insight into how emissions vary with voltage. The data on emission rates from commercial cells as a function of cell voltage were compared with similar data developed on bench scale experiments. Other analyses included a comparison of emission rates among different cell technologies and anode effect (AE) kill strategies. Estimated PFC emissions for different definitions of AE were compared with total measured PFC emissions. Finally, the emission rate as a function of AE duration was examined.

E. J. Dolin

Papers

PFC Emissions Reductions: The Domestic and International Perspective.