Five life cycle modules involved in washing a cup in a standard size residential dishwasher are shown in Figure 10.14. 

Figure 10.14:

For simplicity, many operations, emissions, and resources are not included, and flows are reported with only one or two significant figures. The utility mix (75 percent coal, 25 percent natural gas) is somewhat arbitrary, while a 10 percent loss in transmission and distribution is typical. 

1. Write down the technology and intervention matrices for the life cycle of a glass cup. 

2. Assuming that a single glass cup is used 800 times, determine the corresponding final demand, and calculate the life cycle emissions. 

Determine the scaling vector and draw the corresponding life cycle network diagram. You may assume that one dishwasher load is 80 cups.

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0.22 m³ natural gas 0.49 kg coal 0.4 kg CO₂ Production of high voltage electricity at 1kWh HV plant from natural gas electricity, NG 1 kg CO₂ Production of high voltage electricity at plant from coal 0.25 kWh HV. electricity, NG 0.75 kWh HV electricity coal 1kWh HV electricity, coal 0.09 m³ natural gas HV electricity mix stepped down to LV distribution line 1.6 kWh 1 load Operation of dishwasher cycle LV electricity clean dishes Figure 10.14 Life cycle inventory modules relevant to a glass cup. 2 g NOx Manufacture of glassware 0.9 kWh HV electricity, NG 1 unit glass cup