Transcript Life Cycle Assessment (LCA)
Life Cycle Assessment (LCA)
Sustainable Operations Prof. Gil Souza Life Cycle Assessment (LCA) 1
Quizzes
• For each pair of products / processes below, which one has the lowest environmental impact?
– PET or aluminum packaging for soft drinks?
– Remanufacturing or recycling?
– Paper or plastic bags?
– Ethanol or gasoline for powering automobiles?
– Compact dish detergent or regular dish detergent?
– LED lights or CFL lights or incandescent lights?
Life Cycle Assessment (LCA) 2
Answer: You Need Life Cycle Assessment (LCA)
• • • LCA’s goal is to find the full range of environmental (and societal) damages assignable to products (or a process) through its entire life cycle – Raw material extraction and processing, manufacturing, distribution, use, and disposal / recycling Common categories of assessed damages (but not limited to) – Global warming, toxicity (air, water, and land), ozone layer depletion, acid rain, depletion of minerals and fossil fuels Data intensive process, usually done through software and existing databases Life Cycle Assessment (LCA) 3
Structure / Scope of LCA
Life Cycle Assessment (LCA) Cradle to Gate Includes 4 stages Cradle to Grave Includes 6 stages Source: P&G website 4
LCA Phases (ISO 14040 and 14044)
Goal and Scope Definition
(Determining boundaries for study)
Inventory Analysis
(Data on inputs and outputs quantities for all relevant processes)
Impact Assessment
(Contribution to impact categories, such as energy consumption, through normalization and weighing Life Cycle Assessment (LCA)
Interpretation
(Major contributions, sensitivity analysis: what can be learned from study?) 5
Step 1: Determining Goal
• • • Level of specificity in the study – Is the product being analyzed specific to a company or a plant? Two different plants producing the same type of product could have different emission levels, for example • This requires an additional level of data collection that may be impractical – Or, will we focus on industrial averages (e.g., impacts of using recycled aluminum in a design)?
Level of accuracy in data collection / analysis – – Should be high if used in driving public policy If used in internal decision making for a firm, a reasonable estimate is generally enough How to display the results. Example: comparing two products – Comparison should be made in terms of equivalent use – Example: bar soap vs. liquid soap; the basis should be an equal number of hand washings Life Cycle Assessment (LCA) 6
Life Stage
Resource extraction Product manufacture Packaging and transportation Product use or consumption Maintenance, recycling and disposal
Step 1: Determining Scope Example
Materials choice Product Assessment Matrix Environmental concern Energy use Solid residues Liquid residues Gaseous residues
Step 2: Inventory Analysis
• • • Collect data on the impact of inputs and outputs generated by each row (life cycle stage) on the assessed category of interest. Categories on previous example:
– Gas residues Many databases exist for common materials and processes used (industry averages) Mostly done through software 8 MOT Sustainability
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Materials Choice
• • • Recommendations based on availability on Earth, rate of depletion and toxicity Recommended: – Al, Br, C, Fe, H, Mn, N, O, S, Si, and Ti – Supplies are ample, potential for recycling is good, and have no significant toxicity issues Limit or avoid: – Ag, As, Au, Cd, Cl, Cr, Hg, Ni, Pb – Short supply and/or toxicity problems
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Energy Use (GJ / Mg) in Production of Various Metals
Metal
Steel Copper Aluminum Zinc Lead Titanium
Primary Production
31 91 270 61
Secondary Production*
9 13 17 24 39 Source: P. Chapman and F. Roberts, 1983 9 430 * Consumer recycled material 140 Life Cycle Assessment (LCA)
Solid Residues
• • •
Process residues
– A result of manufacturing process – Example: fly ash from coal combustion
Product residues
– Intended to be part of the product – Example: plastic molding
Packaging residues
– – 30% of all municipal solid waste…but 40% of all U.S. goods are purchased by corporations 11 Life Cycle Assessment (LCA)
Liquid Residues of Common Industrial Processes and Products Process Liquid Species Agriculture Chemical Mfg. Electronics Electroplating Fertilizer Trace Metals
+ •
Nutrients
• *
Solvents, Oils
* * *
Organics
• * +
Acids Suspended Solids
• + + +
Food production Leather making Metal cleaning
+ + * * * * *
Mining, smelting
* •
Pesticides
*
* = Modest influence on local, regional or global scale; + = minor influence on local, regional, or global scale; • = major influence on local, regional, or global scale Source: T. Graedel and B. Allenby, “Design for Environment”.
Example of LCA 1: Paper vs. Plastic Bag
Category
Raw materials Energy to make Solid waste Total emissions to air Global warming equivalents (CO2 equivalents)
Paper Bag
Wood (renewable) 1.7 mJ 50 g 2.6 kg 0.23 kg
Plastic Bag
Oil / gas (non renewable) 1.5 mJ 14 g 1.1 kg 0.53 kg Source: Institute for Lifecycle Energy Analysis Compares one paper bag with two plastic bags (similar carrying capacity) Assumes current recycling rates
It depends!
Life Cycle Assessment (LCA) 13
Example of LCA 2: Impact on Global Warming of Different NEC Products
Electricity cons. (use) 4%
Cell Phones
Assembly at NEC 7% Purchased parts 88% Distribution 0,5% Disposal 0,5% Distribution 0,4% Disposal 0,1%
Fax Machines
Purchased parts 23% Electricity cons. (use) 76% Assembly at NEC 1% Assembly at NEC 1%
Desktop PCs
Electricity cons. (use) 39% Purchased parts 59% Distribution 1,0% Disposal 0,2% Life Cycle Assessment (LCA) Purchased
Switching Equipment
Assembly parts 2% at NEC 1% Electricity cons. (use) 98% Source: www.nec.co.jp
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Example of LCA 3: Lamps (Energy Consumption)
Lamps in Comparison (Use During 25,000 Hours)
3500 3000 2500 2000 1500 1000 500 0 Use [kWh] Production [kWh] 25 x GLS 3290 15,3 2.5 x GFL 658 10,2 1 x LED 658 9,9 Life Cycle Assessment (LCA) Source: www.osram-os.com
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Example of LCA 3: Lamps (Toxicity Potential)
• Toxicity here is mainly caused by power consumption due to by-products: arsenic, sodium dichromate, hydrogen fluoride • Measured in 1,4 dichlorobenzene equivalent Life Cycle Assessment (LCA) 16
Example of LCA 4: Corrosion Protection Systems (After Scaling)
Source: Technical University of Berlin Life Cycle Assessment (LCA) 17
Example of LCA 5: Materials for Residential Construction
Life Cycle Assessment (LCA) Source: Kozak and Galston (2001) 18
Application of LCA Which option is better for the environment: remanufacturing or recycling?
Answer: It depends!
(But remanufacturing is typically better) Life Cycle Assessment (LCA) 19
Example A. Two Automotive Parts (Low Level of Technological Obsolescence)
Energy consumption (KWh/ton) for aluminum part (transmission): alternatives for end-of-life Energy consumption (KWh/ton) for steel part: (gear) alternatives for end-of-life
30000 25000 20000 15000 10000 5000 0
29450
Disposal
4405
Recycling
2597
Remanuf.
7000 6000 5000 4000 3000 2000 1000 0
6205
Disposal
3150
Recycling •In “disposal” a new part has to be produced from virgin raw materials •In recycling, a new part is produced from recycled materials •In remanufacturing, the part is remanufactured and reused
Remanufacturing
is clearly better!
Life Cycle Assessment (LCA) Source: Bert Bras (2009)
742
Remanuf.
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Example B. Cell Phones: Impact on Global
Warming
(
Primarily Energy Consumption
)
Electricity cons. (use) Assembly at 4% NEC 7%
Cell Phones
Purchased parts 88% Distribution 0,5% Disposal 0,5% Most carbon footprint (and also energy use) occurs in purchased pars (manufacturing and raw material extraction.)
Remanufacturing
is best! Life Cycle Assessment (LCA) 21
Example C. Desktop PCs: Impact on Global
Warming
(
Primarily Energy Consumption
)
Desktop PCs
Distribution 1,0% Disposal 0,2% Electricity cons. (use) 39% Purchased parts 59% Assembly at NEC 1% Most carbon footprint (and also energy use) occurs in purchased pars (manufacturing and raw material extraction.)
Remanufacturing
is best! Life Cycle Assessment (LCA) 22
Example D. Internet Switching Equipment: Impact on Global Warming (Primarily Energy Consumption) Purchased parts 2%
Switching Equipment
Assembly at NEC 1% Electricity cons. (use) 98% Most carbon footprint (and also energy use) occurs during the use.
Recycling
is best, if newer equipment is more energy efficient! Life Cycle Assessment (LCA) 23
Example E. Refrigerators: Impact on Cumulative Energy Consumption Distribution Manufacturing Use Again, most energy consumption occurs in usage. Best to replace old appliances with energy efficient new appliances.
Recycling
is best! Sustainable Operations Source: Quariguasi Frota Neto et al. 2008 24
Limitations of LCA: Examples
• • • • •
Weights given to different impacts
– What is more important? Use of water resources or CO2 emissions?
Drawing the boundaries
– Cradle to Gate or Cradle to Grave
?
– Do we consider supporting activities for the system?
• Example: a warehouse stores the product. Direct energy consumption for the warehouse should be part of the system, but emissions associated with garbage pickup for the facility probability shouldn’t be.
Social and economic impacts
– Environmental impacts are relatively easy to measure, but socio economic impacts are difficult to quantify
Renewable vs. non-renewable resources Remanufacturing, recycling, and reuse
– Consideration of recycling makes significant impact, even though that depends on recycling rates Life Cycle Assessment (LCA) 25
Further Resources
• • • The web has an incredible amount of information on LCA For starters, please check the document “LCA_guide_EPA.pdf” on Angel, which has a more detailed guide to LCA (by the EPA), and it includes a list of software vendors See http://www.life-cycle.org/ Life Cycle Assessment (LCA) 26