EIO-LCA
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Revision as of 16:16, 24 May 2007
Economic Input-Output LCA, or EIOLCA involves use of aggregate sector-level data quantifying how much environmental impact can be directly attributed to each sector of the economy and how much each sector purchases from other sectors. Combining such data sets can enable accounting for long chains (for example, building an automobile requires energy, but producing energy requires vehicles, and building those vehicles requires energy, etc.), which somewhat alleviates the scoping problem of traditional process LCA. However, EIO-LCA relies on sector-level averages that may or may not be representative of the specific subset of the sector relevant to a particular product. The term hybrid LCA is used to describe approaches to blending data from EIO and process models to improve accuracy of estimates. The eiolca.net website is a freely available software implementation of EIOLCA using data sources described below.
eiolca.net
The Economic Input Output-Life Cycle Assessment software traces out the various economic transactions, resource requirements and environmental emissions require for a particular product or service. The model captures all the various manufacturing, transportation, mining and related requirements to produce a product or service. For example, you might wish to trace out the implications of purchasing $ 46,000 of reinforcing steel and $ 104,000 of concrete for a kilometer of roadway pavement. Environmental implications of these purchases can be estimated using EIO-LCA. The current (1997) model is based upon the Department of Commerce's 491 sector industry input-output model of the US economy.
What are the data sources for the eiolca.net software?
The data in eiolca.net is developed from a variety of public datasets and assembled for various commodity sectors. For the most part, the data is self-reported and is subject to measurement error and reporting requirement gaps. For example, automotive repair shops do not have to report to the Toxics Release Inventory. The major data sources include:
- Input/Output Matrix: 1992 commodity/commodity input-output (IO) matrix of the US economy as developed by the US Department of Commerce. The matrix includes 485 commodity sectors.
- Economic Impacts are computed from the IO matrix and the user input change in final demand. Economic Impacts are reported in 1992 $ millions.
- Electricity use includes manufacturing and mining sectors developed from the 1992 Census of Manufacturers. Service sector electricity use is estimated using the detailed IO workfiles and average electricity prices for these sectors.
- Fuel and ore use is calculated from commodity purchases (contained in the IO workfiles) and average 1992 prices.
- Energy use is calculated by converting fuel use per sector and 31% of electricity use into Terrajoules (31% is the amount of electricity produced in 1992 from non-fossil fuel sources).
- Revision: Fuel, Electricity, and Energy use have been revised. Please refer to this report.
- Fertilizer use is calculated from commodity purchases (contained in the IO workfiles) and average 1992 prices.
- Conventional Pollutant emissions are from the U.S. EPA AIRS web site, using a concordance to the input-output sectors.
- Greenhouse Gas Emissions calculated by emissions factors from fuel use using U.S. EPA AP-42 emissions factors for CO2 and Methane. N2O emissions estimated to be 10% of NOx emissions. Global Warming Potential (GWP) values converted into CO2 equivalents using the Adriaanse report. Adriaanse, A., "Environmental Policy Performance Indicators - A Study on the Development of Indicators for Environmental Policy in the Netherlands," Sdu Uitgeverij Koninginnegracht, May 1993.
- Toxics Releases are derived from the US EPA's 1995 toxics release inventory (TRI) and 1995 value of shipments from the 1995 Annual Survey of Manufacturers.
- CMU-ET is a weighting scheme for toxic emissions to account for their relative hazard. It is computed from occupational exposure standards (called threshold limit values). The gross amount of toxic emissions is converted into metric tons of sulfuric acid emissions equivalent. More information is available here.
- RCRA (Resource Conservation and Recovery Act) Subtitle C hazardous waste generation, management and shipment was derived from the 1993 biannual US EPA report.
- External costs are calculated from conventional air pollutant emissions and estimates of pollution damage taken from the economics literature. Detailed information on these values are available from the following source: H. Scott Matthews and Lester B. Lave, "Applications of Environmental Valuation for Determining Externality Costs," Environmental Science and Technology, Vol. 34, No.8, 2000.
- Water data from U.S. Department of Commerce, "Water Use in Manufacturing," 1982 Census of Manufactures, Subject Series, Washington, DC: U.S. Department of Commerce, Economics and Statistics Administration, Bureau of the Census, MC82-S-6, March 1986.
- OSHA Safety Data from the following sources:
- U.S. BLS (Bureau of Labor Statistics). 1994. Survey of Occupational Injuries and Illnesses 1992. Washington, D.C.:U.S. Department of Labor.
- U.S. Department of Labor, Bureau of Labor Statistics, Census of Fatal Occupational Injuries, 1992 - 1998.
- Employment data from the following sources (by use):
- 1997 Economic Census: Comparative Statistics for United States 1987 SIC Basis
- U.S. BLS 1997. Industry Illness and Injury Data 1997
- Statistical Abstract of the United States (1998-200)
- National Marine Fisheries Service. 2000. Employment, Craft, and Plants (Table) Processors and Wholesalers 1999
- Bureau of Transportation Statistics. Employment in For-Hire Transporation and Selected Transportation-Related Industries http://www.bts.gov/btsprod/nts/Ch3_web/3-19.htm
- USDA. Agricultural Exports and the Rural Economy in the 1990's http://www.ers.usda.gov/publications/rct71/rct71f.pdf
