1. Process-Based Life Cycle Assessment: H. Scott Matthews Civil and Environmental Engineering / Engineering and Public Policy Carnegie Mellon University

2. Admin Issues HW #1 due today Friday Sessions –And last 2 weeks of February HW #2 Out tonight

3. Simplified LCA procedure in practice Draw a process flow diagram Identify required data Based on the data quality requirements set, start to gather data from (1) on-site visit, (2) survey, (3) literatures, (4) model calculation, (5) databases. Data validation Prepare an inventory table

4. Streamlined LCA Reading on website (for today) Summary, anyone? Admits there is a “continuum” or spectrum of needs and requirements when doing LCA –Suggest various boundaries appropriate –Choices of inputs/output/etc ok

5. LCA patterns of use More for larger firms than smaller. More a tool for a pull strategy than for a push strategy. Acceptance substantially vary among countries (more accepted by developed countries than developing countries). LCA started to become a part of the regulatory system in Europe but not in the US.

6. Source: Frankl&Rubik, 1999 Important applications of LCA perceived by industries

7. Disposal Use Resources and materials Manufacture Example of process-flow diagram (aggregated): Source: Hauschild, 2003 Product system of a uniform (cloth)

8. Example of “required data” table (Inputs and outputs table - part) (source: International Aluminum Institute, 2003)

9. Example of inventory result (part) (source: International Aluminum Institute, 2003)

10. Revisit Example - walking through how to use NREL data - Electricity Generation

11. Data We Have from NREL Electricity Generation Anthracite and Bituminous Coal Production and Combustion Natural Gas Extraction and Processing Nat Gas Combustion Uranium Production and Consumption Oil Combustion in Power Plants Petroleum Refining Biomass combustion in power plants Rail, truck, etc. transportation

12. If we want to identify CO2 used to make electricity How might we streamline? And why? Assumptions? Validity?

13. To make 1 kilowatt-hour (kWh) of electricity..

14. Conversions from Last time.. What is total energy (GJ) required to make electricity? Conversions: 1 lb coal ~ 12000 BTU –1 BTU =1054 Joule; –Gasoline ~ 125000 BTU/gallon –Distillate (e.g., diesel) ~ 135,000 BTU/gallon – Residual ~ 150,000 BTU/gallon –1 ft^3 of natural gas ~ 1000 BTU –Truck transportation ~2500 BTU/ton-mile

15. Source: EIA Annual Energy Review, 2006

16. Draw our Streamlined Process (LCA) Diagram

17. Some Factors of Interest Bituminous Coal Combustion –2250 lbs CO2 / 1000 lbs coal Bituminous Coal Production –4 lbs methane/1000 lbs coal (Methane = 21x CO2) Nat gas extraction / processing –0.64 lbs methane / 1000 cubic feet gas Nat gas extraction / processing –122 lbs CO2 / 1000 cubic feet gas Uranium Production –1750 lbs CO2 / 1000 lbs Uranium dioxide

18. Our weighted average 1 kWh of electricity requires.. –0.53 lbs coal + 1.82 cu ft gas + 1.4 E-6 lbs UO 2 + (all other fuels) CO2 Per kWh: 0.53*(2250+80)/1000 + 1.82*(122+12)/1000 + (1.4 E -6 )*1.75 –1.2 +.24 + ~0 –1.45 lbs CO2 / kWh –Comments so far?

19. Validate: E-GRID http://www.epa.gov/cleanenergy/egrid/index.htm Note: Combustion only! Nat gas: 1.1 lbs/kWh Coal: 2.2 lbs/kWh So our overall total given 50% coal, 19% gas should be at least.. – 0.5*2.2 + 0.19 * 1.1 = 1.1 + 0.2 = 1.3 lbs CO2/kWh

20. Thoughts Our streamlined “LCI” of electric generation in the US (with many caveats) quickly approaches the value used by DOE/EPA Should we add other types of generation? Expected effects? How much is enough? What does ISO tell us?

21. Paper vs. Plastic Grocery Sacks: Comparison of Three Studies Allen & Bakshan i Graedel & Allenby Ciambro ne PE 60,790 sacks Energy [M BTU] 40 34 Air pollution [lb] 737659 Paper 30,395 sacks Energy [M BTU] 504939 Air pollution [lb] 19519849

22. In-Class Assignment Suppose you need to choose a new copier for an office. In a small group: –Define appropriate goals and scope for a life cycle cost and environmental life cycle assessment. –Define appropriate environmental indicators (e.g. electricity or energy use). –Define major benefit or cost categories to consider –Develop a set of processes to be considered (i.e. inputs and outputs identified and estimated). We will have reports from groups by end of period.

23. Example: Copier LCA In GaBi demo, explore under Processes, Production, Materials, Metal Look at steel (3 options) Can also see plastic, etc options Double click to see inputs/outputs –Generally shows normalized impacts for 1kg of output item (eg 1 kg of ABS plastic) –The data records refer to a process that requires many inputs, and produces 1 kg of ABS plastic (as well as many other outputs)

24. Complexity We’ve been looking at fairly small, streamlined LCI problems How does the method scale?