How Green is That Product? An Introduction to Life Cycle Environmental AssessmentHomework #7Goals: In this assignment, youll do the following: apply Carnegie Mellon Universitys Economic Input Output Life Cycle Assessment (EIO-LCA) tool to generate and assess an LCI of ink for the HDPE grocery bag; and read detailed critiques of a published LCA study and determine how this LCA study may have failed with respect to best practice LCA methods.Instructions: When you complete the assignment, return to the Week 7 course page on the Coursera website. Click on the Submit Homework Assignment Answers button, which will allow you to enter your answers into a web form for automated grading. Grading: This assignment is worth 100 points. The point values of each answer are listed below. You can submit a maximum of 30 attempts. The highest scoring attempt that is submitted before the deadline will count toward your official grade. Scores for each attempt will be available immediately after submission of your answers.Numbers: In this assignment, and throughout this course, numbers will be expressed using the U.S. numeric convention where commas separate thousands and the dot (or decimal point) is the decimal separator. For example, the number one thousand two hundred and one-tenth is written 1,200.1.

Part 1: The Economic Input-Output Life Cycle Analysis (EIO-LCA) Tool Thus far, weve included the manufacture and transport of ink for labeling of HDPE grocery bags within the system boundary of the HDPE grocery bag LCA model. In this problem, youll use Carnegie Mellons EIO-LCA tool to generate a rough LCI of the ink required for the HDPE grocery bag, and use these results to determine if ink production and transport should be included in or excluded from the LCA moving forward on the basis of simple mass, energy, and environmental cut-off rules. In your analysis, youll assume the following: Each 5 gram HDPE grocery bag requires 0.01 ml of ink (to print a logo on the bag) The density of ink is 1.2 kg/liter The 2002 producer price of ink is $2 per literGo to the EIO-LCA website at http://www.eiolca.net/ and click on Use the tool. Select the US 2002 (428 sectors) Producer model in Step 1. In Step 2, select the Paint, adhesives, cleaning, and other chemicals sector, then select the printing ink manufacturing sector. In Step 3, use the default value of $1 million of economic activity, which means youll analyze $1 million worth of output from the printing ink manufacturing sector. In Step 4, youll need to select the results categories listed in Table A one at a time. Then, in Step 5, click run the model. For each result category, observe the Total for all sectors value, which appears in the second row of the results table. The total for all sectors is the sum of results for all 428 sectors in the U.S. economy; in other words, this is the LCI total for the selected elementary flow.Based on your results for all required results categories, fill in the answers in Table A. (3 points for each correct answer). Enter only the numerical value (i.e., dont enter the units), and use two decimal places after the decimal separator in your answers (e.g., X.XX).Table A: EIO-LCA results for $1 million of output from the printing ink manufacturing sector

CategoryUnitTotal for all sectorsQuestion

EnergyTotal energy (TJ)1

Conventional air pollutants:

NOxTotal metric tons2

PM10Total metric tons3

SO2Total metric tons4

VOCsTotal metric tons5

Finally, assume that weve set the following cut-off criteria for our HDPE grocery bag LCA. Note that for exclusion, an input must meet ALL THREE CRITERIA:1. All inputs that cumulatively contribute less than 1% of the total system mass input can be excluded2. All inputs that cumulatively contribute less than 1% of the total system energy input can be excluded3. All inputs that cumulatively contribute less than 1% of the total system emissions of NOx, PM10, SO2, and VOCs can be excludedTo make the cut off determination for ink production and transport, youll need to follow these steps:I. Open the Week 7 version of the HDPE grocery bag LCA spreadsheet file, which is available in the Project Files section of the course website.

II. Refer to the combined mass (kg) of the HDPE grocery bag and its required cardboard packaging on the Scaling tab. Calculate the mass of ink required per bag. Does the ink comprise less than 1% of the total combined mass of the ink, HDPE grocery bag, and cardboard packaging?

III. The data in Table B express the primary energy use and pollutant emission intensities associated with the transport of ink to the HDPE grocery bag manufacturing plant. Assume that the transportation distance is 1000 km. Based on the intensities in Table B, calculate the primary energy use and pollutant emissions associated with shipping the mass of required ink (from Step II) a distance of 1000 km. (3 points for each correct answer)Table B: Primary energy use and emissions for ink transport (1000 km)

FlowIntensityResultQuestion

Primary energy1.45 MJ/t-kmMJ6

Conventional air pollutants:

NOx0.66 g/t-kmg7

PM100.03 g/t-kmg8

SO20.01 g/t-kmg9

VOCs0.05 g/t-kmg10

IV. Calculate the 2002 producer price associated with the amount of ink required for a single HDPE grocery bag. Then, multiply this price by the EIO-LCA results in Table A to determine the total primary energy use and pollutant emissions associated with producing the ink required for a single HDPE grocery bag. Enter your answers in Table C. Hint: Note that units of (TJ/million dollars) in Table A reduces to (MJ/dollar) e.g., 10 TJ/million dollars = 10 MJ/dollar -- and that units of (metric tons/million dollars) in Table A reduces to (grams/dollar)e.g., 10 metric tons/million dollars = 10 g/dollar. (3 points for each correct answer)

Table C: Total primary energy use and pollutant emissions associated with producing ink for one HDPE grocery bag

CategoryResultQuestion

EnergyMJ11

Conventional air pollutants:

NOxg12

PM10g13

SO2g14

VOCsg15

V. Add your results from Tables B and C to arrive at the total estimated primary energy use and pollutant emissions associated with producing and transporting the amount of ink required for a single HDPE grocery bag.

VI. Refer to the primary energy inputs total on the Primary Energy Total tab of the Week 7 HDPE grocery bag spreadsheet. This total (0.45 MJ) was calculated, in part, by multiplying the mass quantity of each fuel input from nature by its calorific value. Does your estimated primary energy use for ink production and transport (from Step V) comprise less than 1% of the total system primary energy inputs?

VII. Refer to the LCI Results tab of the Week 7 HDPE grocery bag spreadsheet. Observe the quantities of NOx, PM10, SO2, and VOCs in the LCI. Compare the quantities of each pollutant you estimated for ink production and transport (from Step V) to the total quantities of each pollutant in the current system (from the LCI Results tab). Does your estimated pollutant quantity for in production and transport comprise less than 1% of the total system pollutant quantity for each pollutant?

VIII. Finally, answer this question (5 points for the correct answer):Based on the stated cut-off criteria, your answers above, and the data on ink volume, density, and producer price provided above, can we confidently exclude ink production and transport from our HDPE grocery bag LCA?Enter yes or no hereQuestion 16

Part 2: Are all LCAs created equal?In 2007, a report titled Dust to Dust: The Energy Cost of New Vehicles From Concept to Disposal released estimates on the life-cycle energy use of various models of automobiles. Among the reports findings was the intriguing conclusion that a Hummer H3 SUV has a lower life-cycle energy footprint than a Toyota Prius hybrid. Unsurprisingly, this claim received a lot of media attention.First, read the following article, which was one of many that publicized this claim:http://articles.philly.com/2007-04-04/news/25242308_1_battery-plant-sudbury-fuel-efficiencyAfter this claim was repeated across the media, two environmental research institutes published analyses of and rebuttals to the Dust to Dust report. Read both of these analyses by clicking on the links below. Peter Gleick, Pacific Institute, 2007, Hummer versus Prius: Dust to Dust Report Misleads the Media and Public with Bad Science. http://www.pacinst.org/wp-content/uploads/2013/02/hummer_vs_prius3.pdf

Heidi Hauenstein and Laura Schewel, Rocky Mountain Institute, Checking Dust to Dusts Assumptions about the Prius and the Hummer: Fact-checking using the GREET life cycle model underlines the deep divide between the Dust to Dust study and all previous scientific work. www.rmi.org/cms/Download.aspx?id=6655&file=T07-01_DustToDust.pdf&title=Dust+to+Dust%27s+Assumptions+About+the+Prius+and+the+Hummer Finally, answer the questions below. Refer to the lecture notes for guidance when answering these questions.

Question 1: The study was criticized for not disclosing its source of funding. In best practice LCA, how should the funding source(s) for a study be disclosed? Select the BEST answer below. (10 points)1. The source(s) of funding should be listed when discussing the target audience in the goal and scope definition.2. The source(s) of funding should be discussed in the interpretation step when discussing the results.3. The source(s) of funding should be listed when discussing the study initiator in the goal and scope definition.4. The source(s) of funding should be discussed in the introduction of the study.Question 2: The study contained comparisons intended for public disclosure. Based on the critiques by RMI and the Pacific Institute, which of the ISO 14040 series of guidelines were not followed? Select ALL that apply. Note that some of the answers below are intentionally false! (10 points total)1. Comparative assertions disclosed to the public should ideally be made on the basis of all environmental impacts, not just energy use2. Comparative assertions disclosed to the public must only use process-based life-cycle inventory analysis3. LCAs with comparative assumptions must undergo critical review by a panel of independent experts before being made available to the public4. For comparative assertions, the impact categories and characterization models need to be scientifically valid and generally accepted5. Comparative assertions disclosed to the public must explicitly discuss how the public should use the results of the study6. Detailed sensitivity analyses are required for comparative assertions disclosed to the publicQuestion 3: The study was criticized for the seemingly low useful lifetime that it applied to the Prius (109,000 miles and 12 years) compared to the useful lifetime applied to the Hummer H1 (379,000 miles and 35 years). Which of these following statements best describes what the study may have gotten wrong as a result of these useful lifetime assumptions? Choose the BEST answer. (10 points)1. The studys choice of functional unit (ostensibly, a mile of travel) was flawed as a result2. The studys choice of system boundaries were flawed as a result3. The studys choices of reference flows for each vehicle option were flawed as a result4. The studys choice of intended purpose (to compare the energy footprints of different vehicles) was flawed as a result

Question 4: Which statements below best describe the conclusions of the RMI critique? Select ALL that apply. Note that some of the answers below are intentionally false! (10 points total)1. They concluded that the that the unpublished assumptions and inputs used in the Dust to Dust study seriously hampered independent understanding of the Dust to Dust studys data sources and modeling methods2. They concluded that the Dust to Dust contained no valuable information or insights on the question of life-cycle energy use of transportation vehicles3. They concluded that errors in simple energy unit conversions the Dust to Dust report suggested that the studys methodology was flawed4. They concluded that the results of the Dust to Dust study could not be independently replicated based on a peer-reviewed, comprehensive LCA model for transportation energy use5. They concluded that the lack of uncertainty and sensitivity analysis in the Dust to Dust study invalidated its resultsQuestion 5: The Pacific Institute critique discussed the issue of false precision. What does this mean? Select the BEST answer below. (10 points)1. False precision refers to the use of data and assumptions that are not disclosed to the reader and therefore cannot be critiqued and/or replicated2. False precision refers to the lack of formal uncertainty analysis on a models results3. False precision refers to the reporting of data with more significant digits than is appropriate, which implies more analytical precision than is realistic for an analysis4. False precision occurs when a study makes specific conclusions based on very large data sets