(Demo) Road and Bridges May 2010 : Page 44
(NOx) and methane. In addition to these, there also are numerous process- related releases as well as specialty gases such as chlorofluorocarbons. EPA has assigned each individual greenhouse gas a potency factor based upon CO2 the universal measure is CO2 lent (CO2 ; equiva- e). Generally, the more fuel combusted, or burned, the more CO2 e is emitted. And asphalt plants burn fuel. The majority of fuel is combusted to dry the aggregate and heat the mix; to a lesser extent, fuel is used to heat the liquid asphalt binder and maintain the temperature of the mix. Therefore, CO2 is the primary greenhouse gas of interest in relation to mix plants. Reporting in Whether state environmental agen- cies will require small sources to report their greenhouse-gas emissions or to obtain air-operating permits is deter- mined on a region-by-region basis, and on a state-by-state basis within a region. What is certain is that EPA will require some specified sources that emit green- house gases to report their emissions. EPA’s Greenhouse Gas Reporting Rule makes a distinction between listed sources and unlisted sources that must report. Asphalt-mix plants are not a listed source category, but they still must evaluate their emissions as part of EPA’s rule. Even though asphalt plants are unlisted sources, if they meet both of the following criteria they are required to report their greenhouse-gas emissions to EPA: • Total fuel combustion capacity great- er than 30 million Btu (MMBTU) per hour; and • Actual greenhouse-gas emissions greater than 25,000 metric tons per year. Again, unlisted sources (including asphalt plants) are only required to report their emissions if they meet both of these criteria. The burners on asphalt drum mix- ers typically exceed the 30 million Btu combustion rate. And so the question becomes, “Does an asphalt plant emit more than 25,000 metric tons of CO2 e per year?” The short answer is that it is highly unlikely for a single mix plant. Unless a facility produces over 1 million tons of mix in a year, CO2 e emissions will likely be below the federal threshold reporting criteria. But a word of caution is in order. Various state agencies have recently im- plemented state greenhouse-gas report- ing rules or are in the process of doing so. Many of the states are coordinating with regional greenhouse-gas initiatives. Some of these state-specific reporting cri- teria require sources to report emissions of as little as 5,000 tons CO2 e annually, which is a level that could result from processing only about 200,000 tons of asphalt mix. Therefore, it is impera- tive that an asphalt-mix plant pay close attention to its state’s reporting require- ments for annual CO2 e emissions. HILL & SMITH INC. HILL & SMITH INC. 1000 Buckeye Park Road Columbus, OH 43207 Phone 614.340.6294 info@hillandsmith.com www.hillandsmith.com Portable Steel Barrier Safe Easy Fast Effective Made in the U.S.A. Circle 774 44 May 2010 • ROADS&BRIDGES
