Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/10/2009
Publication Date: 9/10/2009
Citation: Spokas, K.A., Bogner, J., Chanton, J. 2009. A New IPCC Tier 4 Site-Specific Model for Landfill Methane Emissions Inclusive of Seasonal Methane Oxidation. 6th Annual Climate Change Research Symposium, September 8-10, 2009, Sacramento, California. Available: http://www.climatechange.ca.gov/events/2009_symposium/index.html. Interpretive Summary:
Technical Abstract: This project was initiated in the U.S. by the California Energy Commission (CEC) in cooperation with the California Integrated Waste Management Board and the California Air Resources Board to develop improved methods for landfill methane emissions for the California greenhouse gas inventory. This 3-year project (2007-2010) is developing a science-based, field-validated inventory method which links site-specific information on cover types and landfill gas recovery to climatic models, soil microclimate models, and 1D modeling of methane emissions inclusive of methanotrophic methane oxidation. Project tasks include (1) the development of a web-based JAVA template for collection of limited site-specific information; (2) incorporation (with modifications) of existing field-validated climate and soil temperature and moisture models; and (3) site-specific 1D modeling of methane oxidation and emissions. The final product will incorporate these tasks in a freely-available web-based JAVA tool. This type of methodology is allowed under the Tier IV methodology in the current IPCC National Inventory Methodology for Waste using advanced site-specific modeling tools with field-validation. The current project includes extensive field validation at two California sites (Scholl Canyon; Marina) over a 2-year cycle (>850 emission measurements and >2000 laboratory incubations). In addition, data from three additional California sites being monitored by Waste Management has been made available to the project. Project methods are based on expansion of previously-published field-validated modeling, emissions measurements, and supporting laboratory studies and represent a departure from a 20-year history of estimating emissions based on first order kinetic models focusing on methane generation. Whereas the first order models were the state-of-the-art when there were limited field and laboratory studies of landfill methane emissions and oxidation, we can now develop an improved science-based methodology based on site-specific soils, the presence or absence of active gas recovery under various cover materials, and methane oxidation rates which vary seasonally with changes in soil moisture and temperature. Currently, the model is in beta testing stage and presents an improved image of the dynamics of methane oxidation in the cover soils.