Renewable Biogas Options Dave Parry, CDM parrydl@cdm.com

Overview of Biogas Options Introduction Technologies Biogas Treatment Key Issues Case Studies Summary Introduction (Biogas use drivers, value of energy forms, etc.) Key issues influencing biogas use decisions (economics, air quality, technology) Technologies (Cogeneration: IC engines, gas turbines, fuel cells; Vehicle fuel: CO2 removal, compression) Case Studies (EWA, KC West Point, Lethbridge, Pierce County) Summary

Biogas Utilization Drivers Rising Energy Costs (Electricity, Natural Gas, and Gasoline) Communities Desire to be Green Initiatives to Reduce Green House Gases Increasing Biogas Production (Growth, Codigestion)

Value of Biogas Electric generation assumes 35% elec eff and $0.1/kWh Cogen assumes same elec parameters and 45% heat recovery Natural gas assumed at $1 per therm Biogas boiler at 75% and NG boiler at 80% Vehicle fuel at 2.7$/gal unleaded

Biogas Value Increases With Flow

Biogas Use: Part of an Integrated Energy System Import Utility Electricity Plant Demand Export Generated Electricity Natural Gas Vehicle Fuel Plant Heat Demand Recovered Heat Organic Waste Digester Gas Fuel Gas Heat Effluent Heat Rejection Supplemental Heat Digesters Waste Gas Flares Boilers

Options for Biogas Use

Options for Biogas Use Comparison: Capital Cost Maintenance Cost Emissions (NOx, CO) Variable Gas Quality Gas Quality, Pressure Noise

Biogas can be Utilized in Natural Gas Vehicles

Biogas Treatment Needed for Various Options H2S Reduction Pressure Boosting Siloxane Reduction Particulate Reduction Moisture Reduction From Digester To Beneficial Use CO2 removal and compression required for vehicle fuel Iron Sponge Blower Particulate Filter Heat Exchange and Separator Activated Carbon

Biogas Management: Blending, Holding, and Storage

Gas Treatment Equipment

Cost of Generation is Dependent on Natural Gas Rate and Heat Recovery 0.160 0.140 Natural Gas w/ Heat 0.120 Natural Gas (NG) 0.100 $/kWhe 0.080 NG w/ Heat Recovery Natural gas with beneficial use of heat or biogas with supplemental natural gas for boiler 0.060 Biogas 0.040 0.020 0.000 0.4 0.5 0.6 0.7 0.8 0.9 $/therm

Payback as a Function of Electricity Costs Costs are typically $3k to $4k/kW Payback time is shorter with lower capital costs and higher electricity rate

Case Studies of Successful Biogas Utilization Projects

Encina Water Pollution Control Facility, Carlsbad, CA Natural Gas Digester Gas Aeration and Agitation, Dryer 750 kW 750 kW 750 kW 750 kW

The City of Lethbridge Lethbridge Wastewater Treatment Plant Digestion as energy source Lethbridge Wastewater Treatment Plant Lethbridge, Alberta, Canada

King County, WA South Treatment Plant

Basics for Success Early Buy-in from Stakeholders (Economic, Environmental, Operations, and Social) Life Cycle Cost Effective (Accurate Cost Estimates) Understanding of Regulations and Permits Integrated and Flexible Design (Power, Fuel, Heat) that is adaptable to varying conditions and energy rates Proper Attention to Gas Treatment and Management

Questions?

First Level Slide Major Points More Major Points What You Will Discuss Today More on What You Will Discuss Etc.

Other Samples Point 1 Details Etc. with graph to right

Final Slide Major Points More Major Points What You Did Discuss Today Questions?