Analytic framework for analyzing non-energy uses of fossil fuels as petrochemical feedstocks in the USA

Carbon dioxide emissions from the non-energy use (NEU) of fossil fuels are a significant source of national greenhouse gas (GHG) emissions in the USA. As one of the emission sources that make the largest contribution to the absolute overall level of national emissions, NEU is a “key source” in the U.S. GHG Inventory, accounting for 4.6% of USA fossil fuel emissions in 2002. As suggested by IPCC/UNEP/OECD/IEA [IPCC/UNEP/OECD/IEA. Revised 1996 IPCC guidelines for national greenhouse gas inventories. Intergovernmental Panel on Climate Change, United Nations Environment Programme, Organization for Economic Co-Operation and Development. Paris, France: International Energy Agency; 1997], the U.S. Environmental Protection Agency has designed an approach for characterizing emissions and long-term storage of carbon in NEU, tailored to USA conditions and data availability, which yield results that are more accurate than application of the general assumptions supplied by the IPCC guidelines. In the USA, of the various non-energy uses of fossil fuels, petrochemical feedstocks is the largest, followed by asphalt, lubricants, and other categories. The overall storage factor for petrochemical feedstocks in the USA for 2002, calculated as the quotient of carbon stored divided by total carbon in feedstocks, is 67%. In other words, of the net consumption, 67% was destined for long-term storage in products - including products subsequently combusted for waste disposal - while the remaining 33% was emitted to the atmosphere directly as CO2 (e.g., through combustion of industrial byproducts) or indirectly as CO2 precursors (e.g., through evaporative product use). The basic framework used in this approach could be applied in other countries, and is similar in several respects to the Non-Energy use Emission Accounting Tables (NEAT) model framework developed independently and described by other authors in this issue.