1. Waste Management Ottawa Renewable Energy Workshop West Carleton Environmental Centre April 8, 2011

2. Natural anaerobic decomposition of organic waste in the landfill Natural anaerobic decomposition of organic waste in the landfill Landfill gas is about 50% methane when it is produced Landfill gas is about 50% methane when it is produced Methane is the fossil fuel component of natural gas Methane is the fossil fuel component of natural gas Landfill Gas: A Renewable Resource Page 2©2011 Waste Management Any technology or application that uses natural gas can also use landfill gas

3. Landfill Gas Collection Fifth level 18pt Trebuchet Page 3©2011 Waste Management < Perforated pipe wells are drilled into the waste, about one every 50 meters < The wells are connected to a header pipe. A blower places a vacuum on the header pipe to withdraw the gas. < If it is not used as fuel for a beneficial use, the gas is simply burned off in a flare

4. Electricity Generation - about ¾ of total industry Small power plants at the landfill, or delivered by pipeline to an off- site power plant Industrial Fuel (“Medium Btu”) – about 20% Use in lieu of fossil fuel in steam boilers, cement kilns, heating, leachate evaporation, greenhouses, etc. Natural Gas (“High Btu”) – about 5% (25+) Clean to natural gas specifications, compress, and insert into a natural gas pipeline LNG/CNG Vehicle Fuel – 3 Clean to fuel specifications, compress or liquefy, and store in on-site fueling station or haul to off-site fueling station Types of Landfill Gas Projects Page 4©2011 Waste Management

5. YearNo.YearNo. 1982120073 1986220083 2001220096 2003120102 200422011 YTD1 20062 LFG to Pipeline Quality – Project History Page 5©2011 Waste Management

6. LocationTypeDeveloperOutput/DayStartStatus Puente Hills, CACNGLA County1,000 GEG1993? Bowerman, CALNGPrometheus5,000 LNG Gal2006Inactive Sonoma Co., CACNGSCS Energy500+ GEG2008Pilot Columbus, OHCNGFirmGreen700 GEG2008Inactive Altamont, CALNGLinde/WM 13,000 LNG Gal2009Active Dane Co., WICNGShaw100 GEG2011Active Known LFG to LNG/CNG Projects Page 6©2011 Waste Management

7. Typical Ranges Methane45% - 55% CO235% - 45% Nitrogen4% - 12% Oxygen0.2% - 3% Moisture4% - 6% H2S20 - >1,000 ppm Siloxane5 – 200 mg/m3 NMOCs20 – 500 ppm Landfill Gas Constituents Page 7©2011 Waste Management Methane content is decreased as air is drawn into the collection system. The amount of air intrusion varies with the quality of the well field, priority of operations for odor control and compliance, moisture level of the waste, type of final cover, etc. Other constituent levels vary with the type of waste in the landfill

8. Product Specifications Page 8©2011 Waste Management ConstituentLFGNGCNG FuelLNG Fuel Methane45 – 55%> 96%> 88%> 96% CO235 – 45% < 5% < 50 ppm <5% Nitrogen4 – 12% Oxygen0.2 – 3%< 0.2 – 0.4%< 1%< 0.1% H2S 20 - >1000 ppm < 4 ppm< 16 ppm Siloxanes 5 – 200 mg/m3 ND to No Spec ND

9. Dry process: Applicable to lower sulfur loads Lower capital, high expense for replacement of media Wet process: Applicable to higher sulfur loads Higher capital, lower expense Biological: Applicable to higher sulfur loads Higher capital, lower expense Hydrogen Sulfide Removal Page 9©2011 Waste Management

10. Adsorption of siloxane on activated carbon, activated graphite, or mixed beds comprised of alumina, silica gel, or proprietary media Typically multiple beds purged sequentially (pressure swing adsorption) Siloxane Removal Page 10©2011 Waste Management

11. Two Design Criteria Recoverability: the percent of methane recovered from the landfill gas and available for sale. Low recoverability results in a lower revenue for the project Purity: the methane concentration in the product gas that must meet the appropriate specifications Multiple stages or multiple technologies are used to maximize recoverability and purity CO2 Removal Page 11©2011 Waste Management

12. Zeolite selectively adsorbs CO2 via controlled pore sizes, so larger CH4 particles pass through Multiple beds which are consecutively filled and purged by depressurizing (PSA) High purity (97%) with a single stage Second stage may be used to increase recoverability Also removes about half the oxygen and 10% of the nitrogen, which are similar in size to methane Molecular Sieve – Pressure Swing Adsorption Page 12©2011 Waste Management

13. Solution-diffusion through a non-porous membrane CO2 permeates quickly and pass through the membrane. Methane permeates slowly and bypasses the membrane. Single stage can have high purity or high recoverability, but not both Multiple-stage design combinations to achieve purity specification at acceptable recoverability Does not remove oxygen or nitrogen, but does remove H2S Membranes Page 13©2011 Waste Management

14. Many developers require the landfill owner to operate the gas collection system to maintain nitrogen contents low enough to meet the product specifications. WM avoids this approach because of the constrictions placed on compliance and odor control. Nitrogen removal adds significant capital cost. Suppliers have developed adsorption beds capable of removing nitrogen Nitrogen Removal Page 14©2011 Waste Management

15. MOLECULAR SIEVE SULFUR TREAT MEMBRANE SKID LIQUEFACTION LNG STORAGE Altamont LFG to LNG CH4 = 46% N2 = 12% CO2 = 37% O2 = 1.3% H2S = 100 ppm H2O = 3.4% VOC = 0.3% High BTU Fuel > 96% Methane

16. Capital cost is $2500 to $4000 per scfm of LFG. Most projects require 1500 to 3000 scfm of LFG Total costs range from $5 million to $20 million depending on size, LFG quality, nitrogen removal, liquefaction for LNG WM’s cost for Altamont LNG plant was $15.5 Mil. Production cost is in the $4 to $7 per mmbtu Equates to about $0.60 to $1.00 per DEG Economics Page 16©2011 Waste Management

17. LFG quality specs conflict with LFG collection system operations Cost to produce is about $4 to $7 per mmbtu, about the same or more than natural gas: why invest the capital? Most incentives for LFG are targeted to electricity Premium is available to renewable gas that is put in the pipeline and sold to utilities, who can claim renewable energy credits. Value may be more than fuel incentives. Most areas do not have widespread use of CNG/LNG vehicles or fueling stations Barriers to LFG to CNG/LNG Development Page 17©2011 Waste Management

18. Industry trend toward more CNG trucks, with fueling stations to support CNG fleet, resulting in a broader market for CNG sales. Some geographic areas have higher retail cost of CNG due to local market pricing, transportation cost, and taxes. There is value to controlling future availability and price of fuel Emerging market in US for renewable fuel credits (RINs) By meeting pipeline specs, LFG can be sold to CNG suppliers through existing pipelines, providing flexibility in delivery, production, and type of incentive There appear to be opportunities for development in selected market areas with appropriate incentives Considerations for Development Page 18©2011 Waste Management