drinking cups David Bierschenk Alex Adler

Transcription

1 Energy and CO2 analysis of drinking cups Scott Cronin David Bierschenk Alex Adler

2 Outline Objective Analysis by Phase Life Cycle Assessments Comparison (energy and CO2) Conclusion

3 Objective Compare Energy and CO2 footprints for coffee drinking cups Studied: Polystyrene y Paper Stainless steel Glass Polyethylene y Coffee hour- is it best to bring your own dishes?

4 Embedded Energy and CO2 Assumptions- CES embedded energy and CO2 for all materials 10 oz cup weights (experimentally determined) Paper 7 g Polystyrene 2 g Stainless Steel 120 g Glass 370 g Polyethylene l 40 g

5 Polystyrene- Expanded foam molding 1 Paper- from source 1,2 Stainless Steel- cast (calculated) Polyethylene- Melting energy, negligible CO 2 Glass- cast/blown 1 1 "Reusable and Disposable Cups: An Energy-Based Evaluation" Environmental Management. Vol 18. No.6 pp American Paper Institute US pulp and paperboard industry's energy use, calendar year 1989, New York; cited by Wells (1991).

6 Average Dishwasher Reusable cups washed after every use Energy use: ~80% water, 20% Drying 1 Model uses average household water consumption and drying energy per load gco 2 / kj (electric) 3 assume all energy consumed is electrical Assume 50 dishes / load Average Wash by hand Heat 1/5 gallon of water and air dry source:

7 Two Options: 100% to landfill 50% incinerated (η = 30%), 50% to landfill Sources of energy loss and CO 2 emission i Transport to landfill/incinerator Energy/CO 2 extracted by incineration 1 CO 2 released by decomposition (based on molecular formulas) 1 Hocking, M.B Paper versus polystyrene: A complex choice. Science 251 p. 504.

8 Life Cycle Assessment Styrofoam Paper Styrofoam Paper energy (kj/cup) CO2 (g/cup) Polyethylene Polyethylene l Glass Stainless Steel Glass Stainless Steel energy (kj/cup) CO2 (g/cup)

9 Life Cycle Assessment Disposables: Styrofoam Paper Styrofoam Paper Energy (kj/cup) Landfill Styrofoam Burning Styrofoam Landfill Paper energy (kj/cup) CO2 (g/cup) Burning Paper CO2 Emissions (g/cup) Polyethylene Glass Stainless Steel Polyethylene l Glass Stainless Steel Landfill Styrofoam Burning Styrofoam Landfill Paper Burning Paper energy (kj/cup) CO2 (g/cup)

10 Life Cycle Assessment Disposables: Styrofoam Paper energy (kj/cup) Styrofoam Paper Take home message for Disposables CO2 (g/cup) Incinerating has LITTLE effect on energy/cup and LARGE effect on CO2/cup Energy (kj/cup) Landfill Styrofoam Burning Styrofoam Landfill Paper Burning Paper Polyethylene Glass Stainless Steel Polyethylene l Glass Stainless Steel Landfill Styrofoam Burning Styrofoam Landfill Paper Burning Paper CO2 Emissions (g/cup) energy (kj/cup) CO2 (g/cup)

11 Life Cycle Assessment Reusables: Styrofoam Paper Styrofoam Paper Energy (kj/cup) Dishwashing Hand Washing energy (kj/cup) CO2 (g/cup) CO2 Emissions (g/cup) Polyethylene Glass Stainless Steel Polyethylene l Glass Stainless Steel Dishwashing Hand Washing energy (kj/cup) CO2 (g/cup)

12 Life Cycle Assessment Reusables: Styrofoam Paper energy (kj/cup) Styrofoam Paper Take home message for Reusables CO2 (g/cup) Dishwashing Hand Washing Washing has large effect on energy/cup and LARGE effect on CO2/cup Energy (kj/cup) CO2 Emissions (g/cup) Polyethylene Glass Stainless Steel Polyethylene l Glass Stainless Steel Dishwashing Hand Washing energy (kj/cup) CO2 (g/cup)

13 Break-Even Energy Dishwasher Total energy kj paper ps SS wash glass wash pe wash number of cups Literature break even: glass = 15 for paper, 390 for PS

14 Break-Even Energy Hand-washing paper ps Total energ gy kj SS hand glass hand Take home message for Energy pe hand If using disposable, use PS IF using mug, use PE Much better to wash by hand (20 uses) number of cups Literature break even: glass = 15 for paper, 390 for PS

15 Break-Even CO2 Dishwashing, no incineration 5000 Total CO O2 g paper ps S.S. wash glass wash PE wash number of cups

16 Break-Even CO2 Dishwashing, w/ 50% incineration Total CO O2 g paper inc ps inc S.S. wash glass wash PE wash number of cups

17 Break-Even CO2 Dishwashing, no incineration 5000 Total CO O2 g paper ps S.S. wash glass wash PE wash number of cups

18 Break-Even CO2 Hand-washing, no incineration Total CO O2 g paper ps S.S. hand Take home message for CO2 glass hand PE hand hand washing to make it worth it We should not incinerate disposables for energy number of cups

19 Model Sensitivity to Assumptions Model is very sensitive to assumptions Validity: Total energy in paper : 700 kj/cup Compared with 550 kj/cup 1 Total energy in PS : 400 kj/cup Compared with 200 kj/cup 1 From earlier, the number of cups required by reusables made sense with literature values We believe we were able to get reasonable quantitative data

20 Conclusions Incineration of materials does not save much energy while producing a lot of CO2 Don t doit Washing mugs more economically drastically reduces the number of uses to save energy, CO2 What types of dishes should be used for coffee hour dishes? First choice- bring your own mug (if use it more than 20 times) Second Choice- PS

21 Life Cycle Assessment 0.00% Polyethylene 0.57% 91.63% 7.80% 0.00% Glass 9.23% 9.72% 81.05% 0.00% Stainless Steel 0.85% 16.34% 82.81% 0.17% Styrofoam 0.00% 46.65% 53.18% 0.35% Paper 0.00% 63.39% 36.26% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

22 Life Cycle Assessment 0.00% Polyethylene 0.25% 3.39% 96.36% Glass 0.00% 4.30% 4.52% 91.18% 0.00% Stainless Steel 0.39% 7.52% 92.09% 0.17% Styrofoam 0.00% 46.65% 53.18% 0.35% Paper 0.00% 63.39% 36.26% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

23 Processing Methods- Paper

24 Processing Method- Polystyrene Expanded Foam molding Source: CES Edupack 2005 C9H12

25 Processing- others

26 Average Dishwasher Reusable cups washed after every use Energy use: ~80% water, 20% Drying 1 Model uses average household water consumption and drying energy per load gco 2 / kj (electric) 3 assume all energy consumed is electrical Assume 50 dishes / load Average Wash by hand Heat 1/5 gallon of water and air dry Break even calculation E # usesbreak even = E disposable reusable E wash source: