Life Cycle Assessment of Waste Conversion Technologies April 15, 2004

Outline Background and goals Overall approach CT material and energy balance models CT life cycle inventory models Scenario analysis Key findings

Background AB 2770 included the requirement that the CIWMB’s report on CTs “describe and evaluate the life cycle environmental and public health impacts of CTs and compare them with impacts from existing solid waste management.”

Goals What are the life cycle environmental impacts of CTs and how do these compare to existing MSW management practices? –Landfill –Waste-to-energy –Compost

Overall Approach Define CTs: –Acid hydrolysis –Gasification –Catalytic Cracking Develop material and energy balance for CTs Develop life cycle inventories for CTs Utilize CT inventories and RTI’s solid waste model to analyze future scenarios

Overall Boundaries Pre-processing (if needed) Conversion technology (e.g., gasification) Land Disposal Waste Generated Energy Conversion Technology Subsystem Collection Up-front MRF Land Disposal Emissions Conversion Technology (e.g., gasification) Recyclables Electricity or Fuel Offset Recycling Offset Waste Collection Energy and Materials Input CT Byproducts Beneficial Use Offset Energy and Materials Production Energy and Materials Input Energy and Materials Production Fuel and Electricity Production Energy Input Fuel and Electricity Production Energy Input

Material and Energy Balance Models Developed using ASPEN Plus Used publicly available information –Patent applications –Responses to UC questionnaire Communicated with CT vendors Employed conservative assumptions

Acid Hydrolysis

Gasification

Catalytic Cracking VOC Emissions WaterWastewaterCatalyst Baled PlasticSpent Catalyst & Contaminants Combustion Emissions VOC Emissions Electricity for Internal Use VOC Emissions Electricity CatalystsSpent Catalyst Diesel Product AmmoniaCombustion Air Feed Shredding Feed Cleaning Melting Cracker Distillation Diesel Storage Air Pollution Control Gas Turbine

Scenario Analysis Analyzed future CT scenarios as defined by the Board in the RfP: 2003: three 500 tpd acid hydrolysis plants, four 500 tpd gasification plants, one 50 tpd catalytic cracking plant 2005: one additional 500 tpd gasification plant 2007: two additional 500 tpd acid hydrolysis plants 2010: one additional 500 tpd gasification plant

Waste Management Scenarios Compared Landfill: –Gas venting (worst case) –Gas collection and flare (average case) –Gas collection and energy recovery (best case) Waste-to-energy Compost (organics only) Conversion technologies

Mixed Waste Collection Mixed Waste Transfer Station Landfill 50% direct hauled 50% Landfill Scenario Electricity Production with landfill gas-to-energy

Mixed Waste Collection Waste-to-EnergyAsh Landfill50%Mixed Waste Transfer Station 50% direct hauled Electricity Production Steel Recycling WTE Scenario

Mixed Waste Residuals Mixed Waste Transfer Station Landfill with Gas Collection and Flaring 50% direct hauled 50% Organic WastesOrganics Composting Compost Scenario

Mixed Waste Collection Upfront-MRF (95% sep. efficiency) Gasification Recovered Materials to Recycling Electricity Production Co-Located MRF/CT Facilities 50% Glass 70% Metals 45% Glass 25% Metals Landfill with Gas Collection and Flaring MRF Residuals Gasification Scenario

Mixed Waste Collection Up-Front MRF (95% sep. efficiency) Acid HydrolysisLandfill with Gas Collection and Flaring Recovered Materials to Recycling Ethanol Production Co-Located MRF/CT Facilities 50% Glass 50% Plastic 70% Metals 45% Glass 45% Plastic 25% Metals MRF Residuals Gypsum Byproduct Acid Hydrolysis Scenario

Mixed Waste Collection Up-Front MRF (95% sep. efficiency) Catalytic CrackingLandfill with Gas Collection and Flaring Recovered Materials to Recycling Diesel Production Co-Located MRF/CT Facilities 50% Glass 50% Paper 70% Metals 45% Glass 45% Paper 25% Metals Commercial Collection (presorted plastic only) MRF Residuals 50% Catalytic Cracking Scenario

Example Mass Balance Data to LCI for Catalytic Cracking Mixed Waste Collection Up-Front MRF (95% sep. efficiency) Catalytic CrackingLandfill with Gas Collection and Flaring Recovered Materials to Recycling Diesel Production Co-Located MRF/CT Facilities 50% Glass 50% Paper 70% Metals 45% Glass 45% Paper 25% Metals Commercial Collection (presorted plastic only) MRF Residuals 50%

Materials and Energy Inputs

Materials and Energy Outputs

Life Cycle Inventory For Catalytic Cracking Process

Life Cycle Inventory For Entire Catalytic Cracking Waste Management System

Key Findings 1.The amount of energy produced by the CTs is significant. 2.For criteria air pollutants, the CTs are not necessarily better than existing options. 3.From a climate change perspective, CTs are generally better than existing management options except for WTE. 4.Inadequate data to assess the potential for CTs to produce emissions of dioxins/furans and other hazardous and toxic pollutants. 5.Similar to recycling, CTs will likely result in greater local environmental burdens and a potential reduction in regional or global burdens.

Key Findings (cont.) 6.It is important for CT facilities to achieve high levels of conversion efficiencies and materials recycling. 7.CTs can decrease the amount of waste disposed of in landfills. 8.CTs can increase materials recovery and recycling with large associated benefits. 9.CTs are not equal in terms of life cycle environmental performance. 10.No CT facilities exist in the U.S. for MSW and therefore there is a high level of uncertainty regarding their environmental performance.

Limitations CT facilities don’t exist in the U.S.: –Limited data –Uncertain feedstock composition –Uncertain pollution control requirements An LCA is not a risk assessment: –Pollutants are totaled across time and locations –Concentrations of pollutants at a given time and location are not captured by a life cycle study

Sensitivity Feedstock composition Conversion efficiency Level of additional recycling achieved versus pass through of inert materials to landfill Pollution control devices and required inputs