Chapter 2ENERGY AND ENVIRONMENTAL RESULTS
INTRODUCTION
This chapter provides a detailed summary of energy requirements and environmental emissions for a woman's knit polyester blouse. The results were developed using a REPA analysis. Results are reported on an equivalent basis of one million wearings of blouses. The analysis considers all primary and secondary packaging components in each part of the system as well as the laundering of blouses. At the end of the chapter, the results of manufacturing one polyester blouse is discussed in detail.SYSTEM DESCRIPTION
In this study, the term "system" refers to the woman's knit polyester blouse and all secondary packaging required to deliver the blouse to the user. This analysis includes, in addition to manufacture of all components from raw materials, transportation of materials and products between each processing step, laundering, and disposition of the blouse.The basis for this study is one million wearings of polyester blouses. It is assumed that each blouse is worn 40 times before being disposed. Also, it is assumed each blouse is worn twice before it is washed. In practice, many blouses are laundered after each wearing. If blouses are assumed to be laundered after each wearing, the energy and emissions for laundering would be twice as great as reported here.
All disposed blouses are assumed to be landfilled, with 16 percent of the postconsumer solid waste combusted with energy recovery. Reuse of blouses (e.g. through donation to a charity or use as rags) is not evaluated in this report.
Table 2-1 displays the component weight data for one knit polyester blouse and the secondary packaging required to deliver the blouses to the retailer. From a survey of retail stores, it was found that numerous ways of packaging blouses are used. The only secondary packaging included in this study is for transporting the apparel from the garment manufacture to the retailer. For this operation, a corrugated shipping is typically used. This shipping box is assumed to hold 50 blouses and weigh 2.0 pounds empty. This study did not include packaging required to take the blouse from the retailer to the consumer's home.
RESULTS AND DISCUSSION
Tables 2-2 through 2-7 describe the results of this complete REPA analysis. Tables 2-2 through 2-4 report the energy requirements for the system, organized in various formats. Tables 2-5 through 2-7 contain data on solid waste generation, atmospheric emissions and waterborne wastes, respectively. At the end of the chapter, Tables 2-8 through 2-10 show the energy requirements, solid waste, and atmospheric and waterborne releases for the manufacture of one blouse.Table 2-1
WEIGHT OF ONE WOMAN'S KNIT POLYESTER BLOUSE AND PACKAGINGFranklin Associates, Ltd.
Weight per blouse Knit polyester fiber .119 pounds Dye .004 pounds Corrugated Shipper .0456 pounds (includes wood packaging) Plastic .0005 pounds
In the discussion of results that follows, two energy values win not be considered significantly different if they are within 10 percent of each other. For solid waste volume, atmospheric emissions, and waterborne wastes, two totals will not be considered significantly different if they are within 25 percent of each other. The percent difference is defined as the difference between the two values divided by the average of the two values. A detailed discussion of the reliability of results can be found in Chapter 1.
Energy Requirements
Total Requirements. Table 2-2 shows the total and net energy for the system. Because 16 percent of postconsumer solid waste in the United States is combusted with energy recovery, an energy credit to the system is reported. Net energy requirements are determined by subtracting the energy credit from the total energy requirements. The energy credit reduces the total energy requirement for the system by less than one percent.Categories of Energy. The total energy for each phase of the system disaggregated by process energy, transportation energy and energy of material resource is shown in Table 2-3. The energy of material resource is the fuel value of the crude oil and natural gas feedstocks used as raw materials (see Chapter 1 for additional explanation).
For all phases, the transportation energy comprises less than one percent of the total energy required by the system. The energy of material resource is less than one percent for every step except PET resin manufacture. Energy of material resource requires almost half of the energy for the resin manufacture step with the other half needed as process energy. Energy of material resource for PET resin manufacture is approximately four percent of the total system energy.
Table 2-2
TOTAL AND NET ENERGY REQUIREMENTS FOR 1,000,000 WEARINGS OF POLYESTER BLOUSESFranklin Associates, Ltd.
Million Btu Total Energy Requirements 1,607.4 Energy Credit from Combustion 6.0 Net Energy Requirements 1,601.4
Approximately 80 percent of the total system energy is process energy for laundering the blouses. This comes primarily from the heating of water for the washing machine. Seven percent of the total energy is process energy for fabric manufacturing. The resin manufacturing process uses four percent of the total energy. The process energy for all other phases in this system is approximately one percent or less of the total energy. Only a very small percentage of the overall energy consumption is required for postconsumer disposal.
Energy Sources. Table 2-4 shows energy categorized by the fuel source for each phase of the polyester blouse system. The quantity of energy used by each phase of the system for electricity generation, process energy, transportation of materials and products, and fuel-based raw materials is listed by the types of fuel resources used to provide that energy.
The primary fuels used for energy in each phase of the polyester blouse system are natural gas and coal. This is because the laundering equipment (washers, dryers, and water heaters) is fueled by either natural gas or electricity. Coal is used to generate more than 50 percent of the electricity used in the United States; therefore, high electricity use translates into high coal use. Petroleum use is the largest energy source for the PET resin manufacture. This is due to the energy of material resource requirement that is included in this phase. Use of wood for fuel is small and is associated only with the production of the paper-based secondary packaging.
Table 2-3
ENERGY REQUIREMENTS FOR 1,000,000 WEARINGS OF POLYESTER BLOUSESSource: Franklin Associates, Ltd.
Process Energy Transportation Energy Energy of Material Resource Total Energy
mil Btu % of total mil Btu % of total mil Btu % of total mil Btu % of total PET Resin Manufacture 64.0 4.0 1.5 0.1 58.6 3.6 124.1 7.7 PET Fiber Manufacture 17.2 1.1 1.1 0.1 0.2 0.0 18.5 1.2 Packaging 1.4 0.1 0.0 0.0 0.2 0.0 1.6 0.1 Dye Manufacture 5.0 3.0 0.1 0.0 - - 5.2 0.3 Fabric Manufacture 110.4 6.9 0.7 0.0 - - 111.0 6.9 Packaging 1.9 0.1 0.1 0.0 0.1 0.0 2.0 0.1 Apparel Production 0.8 0.1 9.7 0.6 - - 10.6 0.7 Packaging 19.7 1.2 0.5 0.0 - - 20.2 1.3 Detergent Manufacture 21.1 1.3 2.2 0.1 6.5 0.4 29.7 1.8 Packaging 10.0 0.6 0.3 0.0 0.5 0.0 10.8 0.7 Laundry 1,273.0 0.0 - - - - 1,273.0 79.2 Postconsumer Disposal - - 0.8 0.0 - - 0.6 0.0 Total 1,524.4 94.8 16.9 1.1 66.1 4.1 1,607.4 100.0
Table 2-4
ENERGY PROFILE FOR 1,000,000 WEARINGS OF POLYESTER BLOUSES
(million Btu)Source: Franklin Associates Ltd.
Energy Profile
Total Energy Natural Gas Petroleum Coal Hydropower Nuclear Wood Other Energy Credit from Combustion Net Energy PET Resin Manufacture 124.1 38.9 64.3 13.8 2.3 4.7 - 0.1 PET Fiber Manufacture 18.5 1.8 2.4 9.3 1.6 3.3 - 0.1 Packaging 1.6 0.4 0.1 0.4 0.0 0.1 0.5 0.0 Dye Manufacture 5.2 1.3 1.1 1.8 0.3 0.6 - 0.0 Fabric Manufacture 111.0 15.2 49.3 29.9 5.4 11.1 - 0.2 Packaging 2.0 0.4 0.2 0.5 0.0 0.1 0.8 0.0 Apparel Production 10.6 0.1 9.8 0.5 0.1 0.2 - 0.0 Packaging 20.2 2.9 1.5 5.2 0.5 1.0 9.1 0.0 Detergent Manufacture 29.7 17.6 9.4 1.8 0.3 0.6 - 0.0 Packaging 10.8 1.9 0.9 2.5 0.2 0.5 4.7 0.0 Laundry 1,273.0 399.5 40.2 535.3 96.2 198.2 - 3.7 Postconsumer Disposal 0.8 - 0.8 - - - - - Total 1,607.4 480.0 179.9 601.0 107.0 220.4 15.2 4.1 6.0 1,601.4
Solid Waste
Table 2-5 shows the total solid wastes for the system. The totals are disaggregated into industrial process wastes, industrial fuel-related wastes and postconsumer wastes. Solid wastes are reported by both weight and volume for each phase of the system. Weight-to-volume conversions for apparel are based on actual landfill measurements made at the University of Arizona under test conditions simulating landfill conditions. The landfill density factor used for apparel is 435 pounds per cubic yard. Several important observations can be drawn from the solid waste data in Table 2-5.General Comments
- 65 percent of the total solid waste by volume is from the laundering phase of the system (predominantly from the burning of fuels)
- Postconsumer disposal of blouses contributes 10 percent by volume to the total solid waste generation
- Fabric manufacture and apparel packaging each account for approximately three percent of the total solid waste
- The remaining phases account for less than two percent each of the total weight and volume
- The industrial waste for this system accounts for 62 percent of the total volume of solid waste, while postconsumer waste account for the remaining 38 percent.
Production
- Over 95 percent of all industrial waste is from the generation of fuels
- • Less than five percent of industrial waste is process waste.
Consumer Use
- 63 percent by volume of the total postconsumer solid waste is from discarded blouses
- 26 percent of the postconsumer solid waste is from wastewater sludges from the laundry operation
- Packaging for the blouses and primary packaging for the detergent generate the remainder of the postconsumer solid waste.
Atmospheric Emissions and Waterborne Wastes
Air and water emissions are presented in Table 2-6 by specific emission. Large amounts of particulates, nitrogen oxides, hydrocarbons, sulfur oxides, and carbon monoxide are released as atmospheric emissions. These emissions are mostly fuel-related. The largest categories of waterborne effluents are dissolved solids, BOD, COD, acid, metal ions, oil, phosphates, iron, and suspended solids. Except for add, metal ions, and iron, these emissions are primarily process-related. All emission amounts reported reflect discharges after control or treatment measures.Table 2-5
SOLID WASTES FOR 1,000,000 WEARINGS OF POLYESTER BLOUSESSource: Franklin Associates, Ltd.
Industrial
Process Wastes Fuel Wastes Total Ind. Wastes Postconsumer Wastes Total Wastes
(lb) (cu lb) (lb) (cu lb) (lb) (cu lb) (lb) (cu lb) (lb) (cu lb) PET Resin Manufacture 29.9 0.6 448.8 9.0 478.7 9.6 - - 478.7 9.6 PET Fiber Manufacture 25.0 1.5 288.0 5.8 313.0 7.3 - - 313.0 7.3 Packaging 4.1 0.1 13.6 0.3 17.7 0.4 - - 17.7 0.4 Dye Manufacture 15.3 0.3 56.8 1.1 72.1 1.4 - - 72.1 1.4 Fabric Manufacture 30.3 1.9 950.7 19.0 981.0 20.9 - - 981.0 20.9 Packaging 6.3 0.4 18.6 0.4 24.9 0.8 - - 24.9 0.8 Apparel Production 30.0 1.9 16.4 0.3 46.4 2.2 - - 46.4 2.2 Packaging 69.2 1.4 198.4 4.0 267.5 5.4 422.6 15.1 690.1 20.5 Detergent Manufacture 231.6 4.6 78.2 1.6 309.7 6.2 - - 309.7 6.2 Packaging 30.6 1.9 98.5 2.0 129.1 3.9 349.1 13.2 478.2 17.1 Laundry - - 17,005.1 340.1 17,005.1 340.1 3,250.0 65.0 20,255.1 405.1 Postconsumer Disposal - - 0.2 0.0 0.2 0.0 2,511.0 155.9 2,511.2 155.9 Total 472.3 14.6 19,173.1 383.5 19,645.4 398.0 6,532.7 249.2 26,178.1 647.3
Chapter 2 (continued)
LCA Table of Contents