Energy and CO2 analysis of drinking cups Scott Cronin David Bierschenk Alex Adler
Outline Objective Analysis by Phase Life Cycle Assessments Comparison (energy and CO2) Conclusion
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?
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
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 889-899. 2 American Paper Institute. 1990. US pulp and paperboard industry's energy use, calendar year 1989, New York; cited by Wells (1991).
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 2 0.06 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 1. http://www.bchydro.com/powersmart/elibrary/elibrary705.html 2. http://www.flatheadelectric.com/energy/appliancewattage.htm 3. source: http://cdiac.ornl.gov/pns/faq.html
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. 1991. Paper versus polystyrene: A complex choice. Science 251 p. 504.
Life Cycle Assessment Styrofoam Paper Styrofoam Paper 0 200 400 600 energy (kj/cup) 20 0 20 40 CO2 (g/cup) Polyethylene Polyethylene l Glass Stainless Steel Glass Stainless Steel 0 200000 0 5000 10000 energy (kj/cup) CO2 (g/cup)
Life Cycle Assessment Disposables: Styrofoam Paper Styrofoam Paper Energy (kj/cup) Landfill Styrofoam Burning Styrofoam Landfill Paper 0 200 400 600 energy (kj/cup) 20 0 20 40 CO2 (g/cup) Burning Paper 20 10 0 10 CO2 Emissions (g/cup) Polyethylene Glass Stainless Steel 0 200000 Polyethylene l Glass Stainless Steel 0 5000 10000 Landfill Styrofoam Burning Styrofoam Landfill Paper Burning Paper energy (kj/cup) CO2 (g/cup) 0 5 10 15 20
Life Cycle Assessment Disposables: Styrofoam Paper 0 200 400 600 energy (kj/cup) Styrofoam Paper Take home message for Disposables 20 0 20 40 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 20 10 0 10 Polyethylene Glass Stainless Steel 0 200000 Polyethylene l Glass Stainless Steel 0 5000 10000 Landfill Styrofoam Burning Styrofoam Landfill Paper Burning Paper CO2 Emissions (g/cup) energy (kj/cup) CO2 (g/cup) 0 5 10 15 20
Life Cycle Assessment Reusables: Styrofoam Paper Styrofoam Paper Energy (kj/cup) Dishwashing 0 200 400 600 20 0 20 40 Hand Washing energy (kj/cup) CO2 (g/cup) 0 50000 100000 150000 CO2 Emissions (g/cup) Polyethylene Glass Stainless Steel 0 200000 Polyethylene l Glass Stainless Steel 0 5000 10000 Dishwashing Hand Washing energy (kj/cup) CO2 (g/cup) 0 2000 4000 6000 8000
Life Cycle Assessment Reusables: Styrofoam Paper 0 200 400 600 energy (kj/cup) Styrofoam Paper Take home message for Reusables 20 0 20 40 CO2 (g/cup) Dishwashing Hand Washing Washing has large effect on energy/cup and LARGE effect on CO2/cup Energy (kj/cup) 0 50000 100000 150000 CO2 Emissions (g/cup) Polyethylene Glass Stainless Steel 0 200000 Polyethylene l Glass Stainless Steel 0 5000 10000 Dishwashing Hand Washing energy (kj/cup) CO2 (g/cup) 0 2000 4000 6000 8000
Break-Even Energy Dishwasher 90000 Total energy kj 80000 70000 60000 50000 40000 paper ps SS wash glass wash pe wash 30000 20000 10000 0 0 20 40 60 80 100 120 140 160 180 200 number of cups Literature break even: glass = 15 for paper, 390 for PS
Break-Even Energy Hand-washing 90000 80000 paper ps Total energ gy kj 70000 60000 50000 40000 SS hand glass hand Take home message for Energy pe hand If using disposable, use PS IF using mug, use PE 30000 Much better to wash by hand (20 uses) 20000 10000 0 0 50 100 150 200 number of cups Literature break even: glass = 15 for paper, 390 for PS
Break-Even CO2 Dishwashing, no incineration 5000 Total CO O2 g 4500 4000 3500 3000 2500 2000 1500 1000 paper ps S.S. wash glass wash PE wash 500 0 0 50 100 150 200 number of cups
Break-Even CO2 Dishwashing, w/ 50% incineration Total CO O2 g 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 paper inc ps inc S.S. wash glass wash PE wash 0 50 100 150 200 number of cups
Break-Even CO2 Dishwashing, no incineration 5000 Total CO O2 g 4500 4000 3500 3000 2500 2000 1500 1000 paper ps S.S. wash glass wash PE wash 500 0 0 50 100 150 200 number of cups
Break-Even CO2 Hand-washing, no incineration 5000 4500 Total CO O2 g 4000 3500 3000 2500 2000 1500 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 1000 500 0 0 50 100 150 200 number of cups
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
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
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%
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%
Processing Methods- Paper
Processing Method- Polystyrene Expanded Foam molding Source: CES Edupack 2005 C9H12
Processing- others
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 2 0.06 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 1. http://www.bchydro.com/powersmart/elibrary/elibrary705.html 2. http://www.flatheadelectric.com/energy/appliancewattage.htm 3. source: http://cdiac.ornl.gov/pns/faq.html