Similar to using processes associated with engineering design or problem solving, the model described herein employs life cycle assessment as a framework for teaching and learning.. This
Trang 1Prepared by…
Mary Annette Rose
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April 2009
Mary Annette Rose, Director, EnviroTech Department of Technology
Ball State University Applied Technology Building Muncie, Indiana 47306
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The consequences of our technological choices— products, processes, and systems—are coming into focus. The historical record demonstrates that technological decisions have both desirable and unpredictable impacts upon human health and the vitality of the environment. More recent scientific evidence examining carbon and mercury cycles indicates that the consequences of our energy and power technologies are global in scale.
As dedicated teachers, we strive to help students develop the analytical and decision‐making skills they will need to make wiser, environmentally–sound choices regarding the design, adoption, use, and disposal of these technologies. The Standards for Technological Literacy (2000, Standard 5 & 13), the National Science Education Standards and the guidelines for environmental
education (NAAEE, 2004) echo a responsibility for building students’ understanding about the interconnectedness of technology and the environment and their assessment and decision‐making skills. This instructional resource packet provides one model for addressing these standards.
Similar to using processes associated with engineering design or problem solving, the model described herein employs life cycle assessment as a framework for teaching and learning. Taken as a whole, the student‐centered resources in this packet guide students through a life cycle assessment process. Alternatively, these individual activities may serve as examples that can then be applied to other environmental issues and technological choices.
At the heart of our modern technological society lies an unacknowledged paradox. Although the United States is increasingly defined by and dependent on technology and
is adopting new technologies at a breathtaking pace, its citizens are not equipped to make well‐considered decisions or to think critically about technology.
National Academy of Engineering &
National Research Council (2002, p. 1)
Standards for Technological Literacy (ITEA, 2000)
5 Students will develop an understanding of the effects of
technology on the environment
13 Students will develop the abilities to assess the impact
of products and systems
National Science Education Standards (NRC, 1996)
As a result of the activities in grades 9-12, all students
should develop:
• decision-making skills
• understandings of population growth, environmental
quality, natural and human induced hazards, and
science and technology in local, national and global
challenges
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What strategies might individuals and communities use to reduce the negative impacts of this decision on the environment and human health?
In addition to building students’ assessment and decision making skills, the learning experiences described here help students meet a variety of learning goals (Table 1).
This document is arranged into three sections. This introductory section provides background
information for the teacher. The second section includes activity sheets that may be photocopied and distributed to students. Worked examples are provided in section three.
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Life Cycle Assessment
Life cycle assessment (LCA) is a tool for identifying and analyzing the impacts— influences, costs, or benefits—of technology upon the environment. Policy makers use the information generated by an LCA to compare the tradeoffs of alternative products, processes, and services and to better inform their policy, adoption, and management decisions. Business and industry leaders use this information to improve the environmental performance of their products and operations, e.g., pollution prevention and recyclability, and inform strategic decisions.
Systems and Sustainability
LCA is built upon principles of systems thinking, sustainability, and life cycle thinking. A system is a group of interdependent components which act together in a unified way. All
technological systems are embedded within larger social, economic, and environmental systems which interact through the exchange of materials, energy, and information. These
inputs and outputs indicate points of impact and dependence between systems.
For a system to be sustainable (i.e., continue to function), the inputs consumed by one system must not exceed the stored or regenerative capacity of the environment from which those inputs originate. Thus, a paper mill which demands trees as a source of pulp must not exceed the supply of an existing forest or the growth rate of that forest. In addition, the outputs of a system—the products, wastes, and emissions—must be benign or degradable by the environmental system, or those undesirable elements must be managed and stored to protect the health of the environment. Life cycle thinking is a powerful decision‐making tool when striving for sustainability.
Life cycle thinking is looking upstream and downstream at the phases of a products life cycle. This “cradle‐to‐grave” perspective emphasizes that a product has environmental, social, and human health impacts at each stage of its life cycle, including the extraction of raw materials, design and production, packaging and distribution, use and maintenance, and disposal. This comprehensive view compels the decision‐maker to consider a full range of impact indicators associated with the inputs and outputs of each system, especially energy consumption, water requirements, solid wastes, atmospheric emissions, human health effects, and other
cumulative impacts to the biosphere.
Trang 6Figure 1 Life cycle of products
Source: United Nations Environment Programme (2007). Life cycle management:
A business guide to sustainability [Image]. p. 12. Retrieved January 8, 2009, from
http://www.unep.fr/scp/publications/details.asp?id=DTI/0889/PA
Conducting a Life Cycle Assessment
The International Standards Organization (ISO) has outlined standards of Life Cycle Assessment (LCA) in its ISO 14040 Standard. This involves four phases, including:
(1) Goal and Scope Definition (2) Inventory Analysis
(3) Impact Assessment (4) Interpretation.
As explained by the Scientific Applications International Corporation (2006) and summarized
in Table 2, each phase consists of several tasks. As with most research assessment activities, the initial phase of LCA begins by clarifying the goals of the assessment, bounding the study, describing the technology in terms of its life cycle, selecting analytical methods, and
planning.
Trang 7Table 2 Process of life cycle assessment
1 Goal Definition
and Scoping
What are the goals and boundaries of the study?
What environmental impacts and indicators will be considered?
What methods and reporting requirements will be used?
What are the assumptions and limitations of the study?
1. Define the goal(s) and essential questions of the study.
2. Describe the product, process, or service in terms of its life cycle.
3. Select the phases of the life cycle that will be examined.
4. Identify and define the environmental effects and indicators (and units of measurement) that will be examined in the study.
5. Identify the data gathering, analytical and reporting methods?
6. List any assumptions limitations of the study.
2 Inventory Analysis What are the major processes of each phase
of the life cycle?
What are the major inputs (water, energy, materials) and outputs (e.g., air emissions, waste) of each process?
What sources of information and methods will be used to quantify the inputs and outputs?
For each life cycle phase…
1 Identify and describe the major processes.
2 Develop a flow diagram for the processes being evaluated.
3 For each process, identify and quantify the inputs (water, energy, materials) and outputs (e.g., air emissions and solid waste).
Relative to the goal and scope of the assessment and evidence, what conclusions and recommendations are reasonable?
to select reliable data sources or methods which yield the desired type and accuracy of data for each of the inputs (materials and energy) and outputs (e.g., air emissions, solid waste, water, effluents, products and by‐products). Common data sources include actual performance measurements, manufacturer specifications, government reports, or industry‐averaged reports. The data for the life cycle inventory (LCI) are compiled into an electronic spreadsheet or database for further analysis and presentation of results. The example provided in Figure 3 shows a flow diagram of mercury used in fluorescent lamps (Cain, Disch, Twarski, Reindl, and Case, 2007).
Trang 8Figure 2 Generic system flow diagram for a single process
In Phase 3, the goal is to evaluate the linkages between the technology under study and its potential impact upon the environment and human health. Major activities of this phase include selecting impact categories (e.g., mercury toxicity of fish, global warming, or human health) and then classifying the LCI results into these categories. To allow comparison of results, the indicators within categories are then characterized in common terms. For
example, all emissions contributing to global warming might be represented in CO2
equivalents. Then, finally each of the impact categories is assigned a rank based on their perceived importance.
Trang 9Figure 3 Flow diagram of mercury used in fluorescent lamps in the United States in 2005
Source: Cain, A., Disch, S., Twarski, C., Reindl, J.& Case, C.R (2007) Substance flow analysis of mercury
intentionally used in products in the United States Journal of Industrial Ecology, 11(3) Retrieved December 7,
2007, from http://www.chem.unep.ch/MERCURY/Call_for_information/US_1214_abe.pdf
In the final phase of LCA, the assessor reviews the goals and results of the assessment and identifies the significant issues. Because estimates and assumptions must be made during Phase 2 and 3 of the LCA, another important task is to recheck and evaluate the data before drawing conclusions, making recommendations, and formally reporting the study to others.
Trang 10Section 2 Student Handouts
Trang 11Life Cycle Thinking
When you use a product, you are participating in one phase of a product’s life. Before the product makes it to you, raw materials are taken (extracted) from the environment and manufactured into a product. Then, the finished product is transported to a distributor where you make a decision about whether to purchase it. Many products, such as a light bulb, also consume energy as you use them. After the product is spent and no longer useful,
you dispose of it or recycle it. This circle is called a product life cycle. A life cycle shows that
every product is connected to the environment.
Do you think about how your decisions to purchase and use a product creates a demand for plants, animals, minerals, and energy? Do you consider how the technologies used to extract, produce, transport, and dispose of products might affect (impact) the environment and your health?
In this lesson, we will use life cycle assessment (LCA) to help us identify and assess how our choices impact the environment. To do so, we will explore one common decision…
Decision:
Should you and your family purchase and install compact fluorescent lamps (CFL) in your house or apartment? How might this decision impact the health of humans and the environment?
Trang 12Life Cycle Assessment (LCA) Name _
Teams of business and industry leaders use Life Cycle Assessment (LCA) to help them make decisions.
The LCA process helps the team identify the environmental and social impacts of a product. An
impact is a change or consequence that results after a choice has been made. Let’s use the four phases of the LCA process to help us make a decision…
PHASE #1 Goal and Scope
One of the first tasks of a LCA is to define your goals and bound your assessment. Bounding means setting limits, such as setting limits on time, place, sources of information, and impact areas. The impact areas of interest could include impacts to the biosphere (humans, animals, and plants), or the hydrosphere (water), cryosphere (ice), atmosphere (air), or lithosphere (land).
Trang 13PHASE #2A Inventory Analysis Name _
In this phase of the LCA, the team takes an inventory of the major systems used during a products’ life cycle. A system is a set of tools and processes (e.g., mining and manufacturing) which work together in a unified way. A system requires materials and energy to function; these elements are called inputs. Processes transform these inputs into desirable products and undesirable outputs (e.g., wastes and emissions). A complete inventory would identify and quantify the inputs, processes, and outputs for the entire life cycle of a product.
Shipping (cargo ship) Selling
Repackaging Burying in a landfill Shaping glass tubes Cleaning up broken CFLs Recycling
Refining ore
Sources Coal Petroleum Natural gas Energy Form Electricity Heat Light
Trang 15PHASE #2B Inventory Analysis Name _
The purpose of your Life Cycle Assessment is to help you make a decision about whether to adopt compact fluorescent lamps. Your Life Cycle Inventory (LCI) would not be complete without counting the number, type, and power ratings of lamps you have in your home or apartment. The unit of power for a bulb is the Watt (W). Common power ratings for CFLs are 23 W and 14 W. This data would help describe the “Use and Maintenance” section of the LCI. For the Disposal section, you will also need information about how you and your parents dispose of spent bulbs.
Directions: Working with team mates, develop an inventory sheet that could be used to record the
number and types of light bulbs in your home or apartment. On this sheet, you might provide a column to record the type, quantity, power rating of lamps and initial cost of lamps. After your team finalizes the inventory sheet, take the sheet home and conduct an inventory of working bulbs in your home or apartment.
How does your family dispose of spent CFL and fluorescent lamps?
What does your family do if a CFL or fluorescent lamp breaks?
Trang 16PHASE #2C Inventory Analysis Name _
A necessary part of a life cycle inventory (LCI) is to quantify the energy used during each part of the life cycle. For the “Use and Maintenance” part of the life cycle, we can use your home inventory to estimate the quantity of energy consumed. Before we begin, you should know that:
(Watt)
Time Bulbs
On
(Hours per year)
Total Bulbs in House
(#)
Power Used per Year
(kWh)
Cost of Electricity per year
($)
Coal Burned per year
Trang 17PHASE #2D Inventory Analysis Name _
When reporting the results of an Inventory Analysis, assessors make a flow diagram which graphically shows where inputs and outputs flow in and out of processes.
Directions: Working with a team, prepare a flow diagram for one part of the life cycle of a CFL, i.e.,
extracting raw materials, producing, transporting, using and maintaining or disposing. As shown in the model below, show the inputs, processes, and outputs associated with this part the life cycle. When you are finished, connect your flow diagram to other teams in the class to form a complete
● ● ●
Trang 18PHASE #2E Inventory Analysis Name
Trang 19Source: Cain, A., Disch, S., Twarski, C., Reindl, J.& Case, C.R (2007) Substance flow analysis of mercury intentionally used in products in the United States
Journal of Industrial Ecology, 11(3) Retrieved Janury 30, 2009, from http://www.chem.unep.ch/MERCURY/Call_for_information/US_1214_abe.pdf