05-06-2013, 12:05 PM
A Geographic Perspective on the Current Biomass Resource Availability in the United States
A Geographic Perspective.pdf (Size: 2.45 MB / Downloads: 22)
Introduction
Biomass is receiving increasing attention as scientists, policy makers, and growers search for clean, renewable energy alternatives. Compared with other renewable resources, biomass is very flexible; it can be used as fuel for direct combustion, gasified, used in combined heat and power technologies, or biochemical conversions. Due to the wide range of feedstocks, biomass has a broad geographic distribution, in some cases offering a least-cost and near-term alternative.
The objective of this research is to estimate the biomass resources available in the United States and map the results. To accomplish this objective, biomass feedstock data are analyzed both statistically and graphically using geographic information systems (GIS). A GIS is a computer-based information system used to create, manipulate, and analyze geographic information, allowing us to visualize relationships, patterns, or trends that are not possible to see with traditional charts, graphs, and spreadsheets.
While other biomass resource assessments concentrate on the economic or theoretical availability, this study estimates the technical biomass resources available in the United States (page 59). The estimates are based on numerous assumptions, methodologies adopted from other studies, and factors that relate population to the amount of post-consumer residue generation. The main contribution of this research is that it adds a geographic perspective to biomass research by answering questions such as where the resources are and how much is available.
Methane Emissions from Manure Management
In manure management systems, methane is produced by the anaerobic decomposition of organic matter. The type of manure management system employed determines the extent to which this process occurs. Types of systems included in the EPA State Workbook3 are pastures, deep pits, liquid slurry, and anaerobic lagoons. Generally speaking, liquid manure management systems, such as ponds, anaerobic lagoons, and holding tanks promote methane production. Manure deposited on fields and pastures, or otherwise handled in a dry form, produces insignificant amounts of methane.
For the purpose of this analysis we included the following animal types: dairy cows, beef cows, hogs and pigs, sheep, chickens (layers and broilers), and turkey. The data on animal population by county was obtained from the 2002 USDA National Agricultural Statistics. All emissions were calculated by animal type and manure management system. The results of these calculations are shown in Figure 12 followed by Table 2 with estimates summarized by state. Please refer to the Analysis Methodology section of this paper for additional information (page 51).
Municipal Discards
Methane Emissions from Landfills
The methane emissions from landfills depend on three key factors: (1) total waste in place; (2) landfill size; and (3) location in an arid or non-arid climate. Data on the landfill locations and the waste in place was obtained from EPA’s Landfill Methane Outreach Program (LMOP), 2003 database. For this study we used the landfill size defined by EPA. A large landfill is one containing more than 1.1 million tons of waste in place. With regard to moisture as a factor in the methane production, landfills in non-arid climates are believed to produce more methane per unit of waste in place than do landfills in arid climates. Therefore different methane emission estimates have been developed for non-arid states and for arid states.
Summary
This research attempted to estimate the biomass resources currently available in the United States, and to examine their geographic distribution. It also addresses the use of GIS as a powerful method for collecting, exploring, analyzing, and visualizing the biomass data. The results of this study show that an estimated 423 million tonnes of biomass are technically available in the country (Table 10). The geographic pattern of this resource availability by county is shown on Figure 25, and Figure 26 illustrates the numbers normalized by county area. The crop, forest, and primary mill residues provide about 70% of the total biomass resources (Figure 28 and Figure 29). While the resources from other feedstocks are relatively insignificant, they could play an important role at a regional and local level.