Industrial Ecology (EAEE E4001) Term Paper by. Kevin James Ho. Undergraduate major in Economics, Columbia College. Instructor: Prof.

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1 Using the Carbon Credits Earned by the Waste-to-Energy Facility of Wheelabrator Sagus, Inc. (MA) to Balance the Carbon Emissions of Columbia University s Morningside Campus Industrial Ecology (EAEE E4001) Term Paper by Kevin James Ho Undergraduate major in Economics, Columbia College Instructor: Prof. Nickolas Themelis Department of Earth and Environmental Engineering Columbia University January 2006 I would like to thank Professor Nickolas Themelis of Columbia University, Maria Zannes, Francis Ferraro, Pat Impollonia, Carl Liggio, Liam Baker, Nick Rella, Andrew Rieb, and my colleagues for their kind support and input. All errors are my own.

2 Donation of GHG Credits by Wheelabrator Technologies Inc. to make Columbia University s Morningside Campus Carbon-Free Executive Summary Wheelabrator Technologies Inc. (WTI), a subsidiary of Waste Management Inc. of Houston, TX, owns and/or operates 17 waste-to-energy (WTE) facilities, including the Saugus WTE facility in Saugus, MA, that processes 500,000 tons of municipal solid wastes (MSW) annually. Every year, WTI earns a large amount of Greenhouse Gas (GHG) credits from GHG savings from its WTE practices. A recent WTI paper reported GHG savings of 73,224 MTCE (metric tons of carbon equivalent), or 240,593 MTCO 2 E (metric tons of CO 2 equivalent) from the Saugus WTE facility. WTI has offered to donate to Columbia University (CU) enough GHG credits earned from its Saugus WTE facility so that CU s Morningside Campus can be deemed Carbon-free. This study sets out to verify that the Saugus WTE facility creates the reported GHG savings, and also to perform a carbon emissions accounting for the CU Morningside Campus (CUMC). The study has found that the WTI report may have under-reported the actual GHG savings from the Saugus WTE facility, and that CUMC s GHG footprint (measured in MTCE or MTCO 2 E) is smaller than the GHG credits WTI earns from the Saugus facility. Thus, WTI indeed earns sufficient GHG credits from the Saugus facility for this donation. Verifying WTI s Report The Saugus facility produces GHG savings in three major ways: Displacing electricity generation by local utilities (coal and oil, in the Saugus case).

3 Displacing virgin steel production due to the recovery of iron and steel scrap at the Saugus WTE facility. Avoiding landfilling of MSW, which directly generates methane (CH 4 ) and indirectly produces CO 2 from the transport of MSW to the landfill. WTI s 2005 report computed the Saugus facility s GHG savings using the MSW decision support tool (MSW DST) developed by RTI International in cooperation with the US Environmental Protection Agency (EPA). The MSW DST performed a life-cycle study of the Saugus facility s MSW management practices, including MSW collection, transport, recycling, and combustion with energy recovery. The life-cycle environmental aspects of displacing local electricity generation, virgin steel production and landfilling were also included. The results of the MSW DST are summarized in Figure 1. Figure 1: GHG Emissions (MTCE) avoided by Saugus WTE facility Waste-to- Energy Electric utility Virgin steel production SC Landfill Total Avoided GHG Figure 1 shows that the Saugus facility emits 70,000 MTCE annually, but saves 90,000 MTCE from displacing local electricity generation, 8,000 MTCE from recycling ferrous scrap, and 45,000 MTCE from avoiding landfilling of MSW, for a net GHG savings of 73,000 MTCE. To verify this figure, Saugus GHG savings were re-calculated using the parameters found in Table 2. For the detailed method of calculation, please see Appendix A to this report.

4 Table 2. Figures used in verifying Saugus GHG savings. Parameter Value Saugus WTE facility emissions MSW processed (annual) Organic matter content of MSW Average molecular structure of organics in MSW Resulting carbon content of MSW 500,000 tons 6 59% C 6 H 10 O 4 29% Displacing Local Electricity Generation Saugus facility power capacity MA 2002 CO 2 from coal generation MA 2002 CO 2 from oil generation Proportion of displaced electricity from coal/oil 40MW 0.91 MTCO 2 /MWh MTCO 2 /MWh 3 50% / 50% Displacing Virgin Steel Production Ferrous content of MSW CO 2 from virgin steel production 4% 12 3,089 kg-co 2 /ton-steel 7 Avoidance of Landfills Landfill (Lee County Landfill, SC) Lee County Landfill CH 4 generation potential CH 4 GHG potential 3,203 ft 3 /ton-msw 4 23 MTCO 2 E/MTCH 4 8 Railroad (transportation of MSW to Lee County, SC) Distance to Lee County, SC Fuel (diesel) efficiency CO 2 from railroads 870 miles ton-mile/gal lb-co 2 /gal-diesel 1

5 The verification calculations (Table 3) revealed that the Saugus annual GHG savings are about 118,000 MTCE, i.e., considerably higher than the Saugus reported GHG savings (73,224 MTCE). On examining the WTI report, it seems that WTI may have: a) underestimated the carbon content of MSW, and b) not considered the fact that CH 4 s GHG potential is 23 times that of CO 2. These two factors combine to explain away more than 90% of the discrepancy. Table 3. Comparison of reported Saugus GHG savings and calculated GHG savings Verification Calculations (MTCE) WTI reported (MTCE) WTE emissions -145,479 ~ -70,000 Displacement of electricity generation 51,034 ~90,000 Displacement of virgin steel production 16,849 ~8,000 Landfilling landfill gas 192,206 Landfilling rail transportation 3,352 ~45,000 Total GHG savings (MTCE) 117,961 73,224 The verification calculations revealed that WTI s claim to GHG credits from its Saugus WTE facility is indeed justified, and that WTI could probably claim significantly more than 73,224 MTCE worth of GHG credits. Columbia University Morningside Campus (CUMC) GHG Footprint CUMC is located in Morningside Heights, New York City. The central campus (see map in Appendix B) spans between Amsterdam Avenue and Broadway, from 114 th St to 120 th St. The greater CUMC campus includes offices, student dormitories, and faculty housing apartments spread around the central campus, ranging between Riverside Drive and Morningside Drive, from 109 th St to 122 nd St. CUMC s GHG emissions come from two sources:

6 Electricity consumption that generates CO 2 at the suppliers power plants CO 2 from combustion of natural gas and #6 (residual) oil in HVAC (Heating, Ventilation and Air-Conditioning) boilers. CO 2 from Electricity Consumption CUMC consumes about 100,000 MWh of electricity every year. Three companies supply this load: Con Edison Solutions (CES), Con Edison (Con Ed) and New York Power Authority (NYPA). Table 4 shows the carbon emission rates of these companies between Table 5 and Figure 6 show the amount of electricity supplied by each company from , and the corresponding CO 2 emissions calculated using the information in Table 3. Table 4. CO 2 emission rates of CUMC s electricity suppliers % of CO2 rate % of CO2 rate % of CO2 rate % of CO2 rate NYS (kg/mwh) NYS (kg/mwh) NYS (kg/mwh) NYS (kg/mwh) NYS* % % % % CES* % % % % Con Ed* % % % % NYPA * Emission rates for CES and Con Ed were reported as percentages of the emission rate for the entire New York State (NYS).

7 Table 5. Electricity supplied and CO 2 emissions from power suppliers 2 CES Con Ed NYPA TOTAL MWh MTCO2 MWh MTCO2 MWh MTCO2 Total MWh Total MTCO2 Total MTCE Clearly, the data shows that CUMC s power consumption is fairly constant, with fluctuations of less than 3%. However, because CES is CU s primary power supplier (supplying 91% of CUMC s power), CO 2 emissions are highly dependent on the emission rate of CES, which has fluctuated between 605 kg/mwh (2001) and 654 kg/mwh (2002). As a result, CO 2 emissions were lowest in 2001 (15,000 MTCE) and highest in 2003 (18,700 MTCE). Fig. 6. CUMC s electricity consumption and resulting CO 2 emissions MWh MTCO2E Consumption (MWh) Emissions (MTCO2)

8 CO 2 from Central Campus HVAC Boilers CUMC s central HVAC system is run by CU Powerhouse, and serves the buildings within CUMC s central campus (between Amsterdam and Broadway, 114 th and 120 th ). The system is powered by four industrial-grade boilers located in the basement of the CEPSR building. These boilers are able to combust both natural gas and #6 (residual) oil as fuel. Carbon emission rates for these two fuels are given in Fig 7. Table 8 shows CUMC s natural gas and #6 oil consumption and the resulting carbon emissions over the last five years (2005 current till April). Fig 7: Carbon emission rates for natural gas and #6 oil 5 Emissions (MTCE) = Fuel Combusted (QBtu) x Carbon Content (Tg-C/QBtu) x Fraction Oxidized x 10 6 (MTCE/QBtu) Fuel Type Carbon Content Fraction (Tg-C/QBtu) Oxidized #6 (Residual) Oil Gas Table 8. CUMC carbon emissions from natural gas/#6 oil consumption Year Oil (DKT) MTCE Gas (DKT) MTCE Total Fuel Use (DKT) Total MTCE ,816 8, ,326 5, ,142 13, ,900 3, ,084 8, ,984 11, ,647 10, ,315 5, ,961 15, ,854 13, ,726 3, ,580 17, (April) 251,292 5,346 55, ,493 6,141 CUMC s carbon emissions from the HVAC boilers have been rising rapidly over the past four years. The critical factor behind this rise is the increased dependence on oil as fuel, which is a

9 result of rising gas prices, making gas more expensive relative to oil. The less critical factor for the rise in emissions is increased energy consumption, which is likely due to the progressively warmer summers and harsher winters in recent years. CUMC 2005 GHG Footprint Table 9 puts together CUMC s carbon emissions from electricity consumption and central HVAC boilers. Clearly, recent history shows that Saugus GHG savings (73,224 MTCE reported by WTI; 117,961 MTCE calculated by this author) are more than enough to cover CUMC s GHG footprint from these two sources (28,000/30,000/32,000 MTCE in 2001/02/03). Table 9. CUMC s total carbon emissions Electricity Consumption (MTCE) Boiler (MTCE) Total MTCE Total MTCO2E Mean Std. dev We can reasonably expect CUMC s 2005 GHG footprint to be near the sum of the means, i.e. 31,063 MTCE. The joint variance of emissions from Electricity Consumption and Boiler yields 2,065 MTCE, and hence the 95% confidence interval (assuming the data is normally distributed) of the CUMC 2005 GHG footprint is (27,015, 35,111) MTCE. Both the expected CUMC GHG footprint and the upper limit of the 95% confidence interval are well within the 73,000 MTCE

10 GHG savings reported by WTI, and certainly well within the 118,000 MTCE GHG savings calculated by this author. However, it must be noted that the central HVAC system examined in this study serves only the buildings within the central campus. While this constitutes the majority of CUMC s GHG emissions from HVAC systems, CUMC s other buildings (e.g. School of Social Work building, offices, student dormitories, faculty housing) have their own boilers to provide heating, cooling and ventilation, which further raise the CUMC GHG footprint. Fuel use data for these other buildings was not available to this author. Thus, it can be concluded that CUMC s 2005 GHG footprint is at least 35,111 MTCE. Twice that amount, or 70,000 MTCE, would be a very liberal estimate, since emissions from HVAC boilers are at most comparable to the central HVAC system s emissions. Conclusions In verifying WTI s reported Saugus WTE GHG savings of 73,224 MTCE, this author found that WTI has likely underestimated the true GHG savings, due largely to the omission of the GHG potential of the CH 4 (23 times that of CO 2 ) that would have been emitted had the MSW been landfilled instead of combusted. Calculations revealed true annual savings of 117,961 MTCE. The CUMC GHG emissions from power consumption averaged 16,684 MTCE between , while emissions from CUMC central campus HVAC boilers averaged 14,379 MTCE between , for a combined average of 31,063 MTCE annually. A simple projection for CUMC s 2005 GHG footprint from these two sources reveals the upper limit of the 95% confidence interval to be 35,111 MTCE. Considering that there are CUMC buildings beyond the central campus (offices, residences) that were not included in the calculation of the CUMC GHG emissions, it is prudent that the WTI donation of carbon credits be 70,000 MTCE, i.e. double the above-calculated emissions, but within WTI s reported GHG savings of 73,000 MTCE, and well within the savings of 118,000 MTCE calculated in this study.

11 References 1. Association of American Railroads. June Railroads and Greenhouse Gas Emissions Columbia University Facilities Management Electricity Consumption by Account/Month from May 2000 April Energy Information Administration (EIA) State Electricity Profiles 2002: Massachusetts 4. Environmental Protection Agency (EPA) U.S. EPA Landfill Methane Outreach Program Landfill Gas Analysis Report for Lee County Landfill Environmental Protection Agency (EPA) In Brief The U.S. Greenhouse Gas Inventory. 6. Ferraro, F Accrediting Greenhouse Gas Credits for Marketing The Saugus Experience 7. Glover, J. August Which is Better? Steel, Concrete or Wood Intergovernmental Panel on Climate Exchange IPCC s Third Assessment Report 9. New York Power Authority Carbon dioxide emissions per kwh for New York State Public Service Commission Environmental Disclosure Labels by LSE Tchobanoglous, G., Theisen, H., and Vigil, S Integrated Solid Waste Management, chapter 4, McGraw-Hill, New York. 12. Themelis, N. J., Y.H. Kim, and M.H. Brady Energy Recovery from New York City Solid Wastes, in press, Journal of Waste Management and Research.

12 Appendix A: Calculations performed in verifying WTI s Saugus GHG savings report Parameter Value Saugus WTE facility emissions Organic matter content of MSW Average molecular composition of organic matter MSW processed (annual) 59% 12 C 6 H 10 O ,000 tons Carbon content of MSW = 59% * ( 6*Ar(C) / Ar(C 6 H 10 O 4 ) ) = 59% * (72 / 146) = 29.1% Emissions = 29.1% * 500,000 tons = 145,479 MTCE Displacing Local Electricity Generation Saugus facility MSW capacity (365 day operation) Saugus facility power capacity MA 2002 CO 2 from coal generation MA 2002 CO 2 from oil generation Proportion of displaced electricity from coal/oil 547,500 tons 40MW 0.91 MTCO 2 /MWh MTCO 2 /MWh 3 50% / 50%

13 WTE facility used capacity = 500,000 tons / 547,500 tons = 91.32% Energy generated from WTE = 91.32% * 40MW * (365*24h) = 222,685 MWh == 445 kwh/ton MSW GHG Savings from displaced energy = 50% * 222,685 MWh * 0.91 MTCO 2 /MWh + 50% * 222,685 MWh * 0.78 MTCO 2 /MWh = 187,124 MTCO 2 = 51,034 MTCE Parameter Value Displacing Virgin Steel Production

14 Ferrous content of MSW CO 2 from virgin steel production 4% 12 3,089 kg-co 2 /ton-steel 7 Recovered steel = 4% * 500,000 tons = 20,000 tons GHG Savings = 3,089 * 20,000 / 1000 = 61,780 MTCO 2 = 16,849 MTCE Avoidance of Landfills Landfill (Lee County Landfill, SC) Lee County Landfill CH 4 generation potential CH 4 GHG potential 3,203 ft 3 /ton-msw 4 23 MTCO 2 E/MTCH 4 8 GHG Savings = 3,203ft 3 /ton * 500,000 tons * m 3 /ft 3 = 45,349,435 m 3 -CH 4 = 45,349,435 / 1,480 (specific volume of CH 4 ) = 30,642 MTCH 4 = 30,642 * 23 MTCO 2 E/MTCH 4

15 = 704,755 MTCO 2 E = 192,206 MTCE Railroad (transportation of MSW to Lee County, SC) Distance to Lee County, SC Fuel (diesel) efficiency CO 2 from railroads 870 miles ton(short)-mile/gal lb-co 2 /gal-diesel 1 GHG Emission Rate = 22.8 lb-co 2 /gal-diesel = (22.8 / 410) lb-co 2 /ton(short)-mile = kg-co 2 /ton-mile GHG savings = * 500,000 tons * 870 miles / 1000 = 12,289 MTCO 2 = 3,351 MTCE Net GHG savings = 145, , , , ,351 = 117,961 MTCE

16 CUMC central campus Appendix B: Map of Columbia University Morningside Campus

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