Comprehensive Greenhouse Gases Inventory for the State of Ohio

Transcription

1 Comprehensive Greenhouse Gases Inventory for the State of Ohio Extended Abstract # Saikat Ghosh, Myoungwoo Kim, Kevin Crist Center for Air Quality, 171 Stocker Centre, Russ College of Engineering and Technology, Ohio University, Athens, Ohio INTRODUCTION The evident warming of climate system is believed to be caused due to anthropogenic increase in atmospheric concentrations of greenhouse gases (GHG) and aerosols. Climate change can have negative impacts on agriculture, human health, water resources, ecosystems and oceanic and atmospheric circulation. 1 Therefore, communities across the globe are taking initiatives to curb GHG emissions. On April, 2007, the U.S. Environmental Protection Agency (USEPA) was issued by Supreme Court to regulate four greenhouse gases, including carbon dioxide (CO 2 ), under the provisions of Clean Air Act. The federal agency, in compliance with the decision, promulgated programs to report and control GHG emissions from major sources. GHG mitigation efforts, however, may have social and economic impacts and therefore, the risks need to be assessed before initiating control measures. A detailed GHG emissions inventory is the foremost step in such process. Being an energy-intensive economy, Ohio is the fourth highest CO 2 state emitter in U.S. 2 and also releases huge amounts of air pollutant gases. Ohio is at increasing risk of noncompliance with federal standards for criteria pollutants and GHG. The new GHG regulations can significantly limit the state to grow its economy in a carbon-constrained world. This paper describes the methodology and findings of a detailed GHG inventory for Ohio that was developed to help assess the opportunities and risks associated with various climate change policies. Previous inventory efforts utilized state or national level aggregate data to estimate net GHG emissions. 2,3 However, local and state emission control measures can be better implemented with higher resolution inventory. Gurney et al. 4 accomplished a high resolution inventory with data from 2002 National Emissions Inventory (NEI), though included fossil fuel combustion sources only. Here, in our estimates, carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) emissions from multiple sectors in Ohio were quantified at high resolution of facility and county level. The resulting database was populated in user friendly website (ohioghg.com) and utilized by researchers to investigate the economic impacts of climate mitigation policies in the state of Ohio. 5

2 OVERVIEW Methodology Emissions estimates are typically product of activity data (e.g. input fuel quantity, livestock population) and emission factors. Such estimation methods are inexpensive, though less accurate, compared to direct measurements with scientific instruments. Emission sources are generally categorized as point, non-point and mobile sources. Point sources are major stationary facilities with fixed geographic location such as power plants and manufacturing industries. Non-point sources comprise small stationary sources (e.g. residential heating and commercial cooking) and diffuse sources such as landfills, agriculture and open burning. Vehicular traffic on roads and highways are included in mobile category. Detailed description of data sources and methods are provided in our report to Ohio Department of development, Chapter 8: Creation of a Statewide Emissions Inventory 5 and the emissions process summary is provided here. Activity data for point and non-point sources during 2008 were retrieved from a state inventory for criteria air pollutants emissions that was compiled by Ohio Environmental Protection Agency (OhioEPA). Emission factors were derived mostly from USEPA AP 42 database and other sources such as California Air Resources Board (CARB), American Petroleum Institute (API), Inter-Governmental Panel on Climate Change (IPCC), and U.S. Energy Information Administration (USEIA). Emissions from point sources burning fossil fuels were computed with process-driven, material/equipment-specific emission factors. The reported fuel feed data were verified and corrected using back-calculation from standard emission factors for criteria pollutants. Since coal is a major fuel for electricity generation in Ohio, plant specific CO 2 emission factors for 25 power plants were calculated from supplier county s coal origin. Non-energy industrial processes such as cement manufacturing in kiln, iron production in blast furnace were also included in point emissions. Fuel combustion in residential heating and small industrial and commercial units were also included as non-point sources. CH 4 and N 2 O emission factors for enteric fermentation and manure management of livestock population were retrieved from USEPA report. 3 GHG emissions from open burning of municipal solid waste and combustion of waste and landfill gases were also included. CH 4 emissions from municipal landfills were provided by OhioEPA. Mobile emissions were processed using USEPA Motor Vehicle Emissions Simulator (MOVES) v2010 with state specific inputs for vehicle miles travelled, registration data, vehicle age distribution, I/M programs and fuel supply and fuel formulation. Five road types and thirteen vehicles classes were simulated within MOVES. Results The mass units for GHG are presented here as CO 2 equivalents of million metric tons (MMTCO 2 ) in compliance with IPCC nomenclature; utilizing their global warming potential ratios of 1, 21 and 310 respectively for CO 2, CH 4 and N 2 O Figure 1 summarizes the total GHG emissions in the state of Ohio. Clearly, fossil fuel combustion in different economic sectors dominates the inventory. Numerous coal-fired power plants are located in the state and therefore, the largest contribution was noted from electricity

3 generating units. The plant specific CO 2 emission factor for coal burning was estimated here and varied significantly from the USEPA provided coefficient based on national averaged carbon content of coal origin in U.S. Mobile emissions were estimated to have next highest contribution to total GHG emissions. Among 13 vehicle classes, passenger car and trucks accounted about 66% of mobile emissions. Also, gasoline and diesel-fueled vehicles shared 75% and 25% of GHG emissions respectively. Fuel combustion in manufacturing industries, residential heating and commercial units emitted about 20, 19 and 14 respectively in MMTCO 2. The fuel distribution of GHG emissions from energy sectors was noted as: 98% coal in electricity generation, while natural gas sharing 55% in industrial manufacturing, 86% in commercial units and 88% in residential heating. Non-energy industrial processes also contributed about 11 MMTCO 2, with significant CO 2 emissions from iron and lime manufacturing. Methane emissions from ruminants accounted about 2.7 MMTCO 2. Figure 1: Greenhouse Gases Inventory summary; Units in million metric tons of CO 2 eq. Figure 2 shows the spatial distribution and emission strength of GHG sources in Ohio. Consensus to general trend, metropolitan areas of Columbus (Franklin county), Cleveland (Cuyahoga county), Cincinnati (Hamilton county) and Toledo (Lucas county) were noted to have highest emissions from non-point and mobile sources due to the high population density. However, less populated counties such as Gallia, Jefferson and Washington have surpassed the metropolitan GHG emissions due to in-situ few large power plants. The highest ranking point sources in Ohio were power plants, particularly Gavin (Gallia county), Stuart (Adams county), Cardinal and W.H Sammis (Jefferson county). A.K Steel (Butler county) was also estimated to emit significant volumes of GHG relative to the highest power plant emitters in the state.

4 Figure 2: Ohio map with geocoded point sources and combined county emissions from nonpoint and mobile sources SUMMARY Table 1 shows the comparison of our estimates against state total CO 2 emissions estimated by EIA 2 based on total fuel consumption in each economic sector. While bottom-up calculations were employed in the current work, the estimates were similar to EIA values. There were no emissions data for other GHG processes and therefore the estimation validation remains incomplete. Though, this work provided a framework to develop GHG inventory for such processes in Ohio and other regions. Table 1: Comparison of our estimates (OU) with EIA for year of 2008 Category OU EIA Fossil Fuel Combustion Electric generation commercial Industrial Residential Transportation

5 ACKNOWLEDGEMENTS Support for the research provided by Ohio Department of Development. Thanks to Tom Velalis of OhioEPA for helpful discussion and input. REFERENCES 1. Pachuri, R.K.; Reisinger, A. Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change; Intergovernmental Panel on Climate Change: Geneva, Switzerland, 2007; pp State CO 2 Emissions; United States Energy Information Administration: Washington, D.C. See (Accessed December 2012) 3. Inventory of U.S. Greenhouse Gas Emissions and Sinks: ; United States Environmental Protection Agency: Washington, D.C., Gurney, K.R.; Mendoza, D.L.; Zhou, Y.; Fischer, M.L.; Miller, C.C.; Geethakumar, S.; de la Rue du Can, S. Environmental Science & Technology. 2009, 43, Assuring Ohio s Competitiveness in a Carbon-Constrained World: A Collaboration between Ohio University and Ohio State University; See (Accessed February 2013). KEYWORDS Greenhouse gases, emissions inventory, Ohio, activity data, emission factor, fossil fuel combustion