A Carbon Footprint Calculator for On-campus Students: Development and Education Jeremy Caves Maiella Leano; Jina Lee; Althea Tupper Rice University 6340 Main Street, Houston, TX Abstract Online carbon footprint calculators lack the specificity to allow students living on a university campus to estimate their personal carbon footprint. Because on-campus students do not receive residential energy bills, are often served by district energy systems, and frequently use common areas beyond their living spaces (such as cafeterias and commons), online carbon calculators, which rely on home energy bills, are of little use. We developed a carbon footprint calculator that allows on-campus students at Rice University to calculate their own carbon footprint. Our calculator accounts for the mix of natural gas powered cogeneration and grid-purchased electricity that provides the inputs to Rice’s chilled water, steam, and electrical services. Within the calculator, students enter data on appliance use (for TVs, blow-dryers, lamps, refrigerators, computers, and microwaves), individual room temperature settings, automobile usage, and air travel. The calculator allocates utility usage in student common areas and cafeterias on a per-capita basis. CO2 emissions are calculated for each entry and scaled to project total student annual emissions. The calculator provides on-campus students with a useful educational tool to help them understand the impact of their daily activities and compare their emissions to the average Rice student, the average American, and the global per- capita average. Additionally, the calculator augments university-wide carbon footprint analyses by identifying trends and choices among students that raise or lower their carbon footprint. The calculator is easily adaptable to other universities, requiring only information on the university’s power source and the percentage of power used by dorms and cafeterias. Calculator Design and Assumptions Dorm Appliance Energy Consumption Using P3 Kill-a-Watt meters, we measured Average energy use of 6 common dorm appliances for a one week period Average energy consumption of a blow-dryer for 10 minutes We split appliances into two groups: shared and individual. Electricity consumption from shared appliances was split among the dorm room occupants. Air-Conditioning We assumed the per-capita A/C energy consumption represented the energy needed to cool a room to 76°, and additional cooling required 4% more energy/degree of cooling. Heating and Hot Water Like air-conditioning, we assumed the per-capita value for heating represented the energy needed to cool a room to 68°, and any additional heating required 4% more steam per degree of heating. Hot water consumption was assumed constant for all students Common Areas and Cafeteria’s Electricity Use To account for common area/cafeteria electricity use, we assumed that appliance use only accounts for 20% of total dorm energy consumption (a calculation based upon an average daily usage of the 7 appliances). The remaining dorm energy consumption was then split equally among all on-campus students. Scaled to account for people per room Total Per- Person Dorm Electricity Use Common Area/Cafeteria Electricity Total Annual CO 2 Emissions Per-capita usage Temperature of room Grid Energy (1.6 lbs CO 2 /Kwh) Rice Central Plant (1.22 lbs CO 2 /Kwh) Per-capita Electricity Consumption Scaled to account for 365 days of use Schematic of Calculator Operation Calculator inputs are labeled in green. Scaling factors listed in red. Outputs are listed in orange. Yellow boxes indicate percent of total power consumption. Students enter the # of TVs, microwaves, etc., temperature of their dorm room, the number of miles they fly and drive each year, and the fuel efficiency of their vehicle into the calculator. The Rice Central Plant produces 30% of Rice’s annual energy demand, producing all the chilled water and steam necessary for the campus. Grid-derived electricity accounts for 70% of Rice’s annual energy demand. Heating A/C Hot Water # of TVs/dorm # of lamps/room # of microwaves/room # of refrigerators/room Do you own a desktop? Do you own a laptop? # of hair-dryer uses/week Acknowledgements We wish to thank Richard Johnson (Rice Director of Sustainability) and Dr. Paul Harcombe (Emeritus Professor of Ecology and Evolutionary Biology) for their assistance and advice in completing this project. We gratefully acknowledge the assistance of Doug Wells, Mark Gardner, and Eric Valentine (Facilities, Engineering, and Planning), Dr. Kyriacos Zygourakis (Chemical and Biomolecular Engineering), and our fellow ENST 302 students. # Miles Driven/Year Fuel Efficiency of Vehicle # Miles Flown/Year 42 passenger miles/gallon 2.7 scaling factor (IPCC) 6% 30% 70% This calculator can be used to identify trends in CO 2 emissions for on-campus students. The average Rice student annually emits 13.3 tonnes CO 2. Electricity consumption is roughly constant (partly a by-product of the calculator design). Air travel spikes during junior year, a reflection of study abroad participation.