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Waste Management

Ottawa Renewable Energy Workshop West Carleton Environmental Centre April 8, 2011

Landfill Gas: A Renewable Resource

• • Natural anaerobic decomposition of organic waste in the landfill Landfill gas is about 50% methane when it is produced • Methane is the fossil fuel component of natural gas

Any technology or application that uses natural gas can also use landfill gas

Landfill Gas Collection

< 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.

Types of Landfill Gas Projects

Electricity Generation

site power plant - about ¾ of total industry Small power plants at the landfill, or delivered by pipeline to an off-

Industrial Fuel (“Medium Btu”)

leachate evaporation, greenhouses, etc.

– about 20% Use in lieu of fossil fuel in steam boilers, cement kilns, heating,

Natural Gas (“High Btu”)

Clean to natural gas specifications, compress, and insert into a natural gas pipeline – about 5% (25+)

LNG/CNG Vehicle Fuel

LFG to Pipeline Quality – Project History

Year 1982 1986 2001 2003 2004 2006 1 2 2 2 2 No.

1 Year 2007 2008 2009 2010 2011 YTD 2 1 3 6 No.

Known LFG to LNG/CNG Projects

Location Type Puente Hills, CA CNG Bowerman, CA LNG Sonoma Co., CA CNG Columbus, OH Altamont, CA Dane Co., WI CNG LNG CNG Developer LA County Prometheus SCS Energy FirmGreen Linde/WM Shaw Output/Day 1,000 GEG 5,000 LNG Gal 500+ GEG Start 1993 2006 2008 700 GEG 2008 13,000 LNG Gal 2009 100 GEG 2011 Status ?

Inactive Pilot Inactive Active Active

Landfill Gas Constituents

• • • • • • • • Typical Ranges

Methane 45% - 55% CO2 35% - 45% Nitrogen Oxygen Moisture H2S Siloxane 4% - 12% 0.2% - 3% 4% - 6% 20 - >1,000 ppm 5 – 200 mg/m3 NMOCs 20 – 500 ppm 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.

Product Specifications

Constituent

Methane CO2 Nitrogen Oxygen H2S Siloxanes

LFG

45 – 55% 35 – 45% 4 – 12% 0.2 – 3% 20 - >1000 ppm 5 – 200 mg/m3

> 96% < 5% < 0.2 – 0.4% < 4 ppm ND to No Spec

CNG Fuel

> 88% < 5% < 1% < 16 ppm ND

LNG Fuel

Hydrogen Sulfide Removal

Dry process: Applicable to lower sulfur loads

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Lower capital, high expense for replacement of media Wet process: Applicable to higher sulfur loads

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Higher capital, lower expense Biological: Applicable to higher sulfur loads

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Higher capital, lower expense

Siloxane Removal

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Adsorption of siloxane on activated carbon, activated graphite, or mixed beds comprised of alumina, silica gel, or proprietary media

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Typically multiple beds purged sequentially (pressure swing adsorption)

CO2 Removal

Two Design Criteria

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Recoverability: the percent of methane recovered from the landfill gas and available for sale. Low recoverability results in a lower revenue for the project

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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

Molecular Sieve – Pressure Swing Adsorption

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Zeolite selectively adsorbs CO2 via controlled pore sizes, so larger CH4 particles pass through

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Multiple beds which are consecutively filled and purged by depressurizing (PSA)

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High purity (97%) with a single stage

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Second stage may be used to increase recoverability

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Also removes about half the oxygen and 10% of the nitrogen, which are similar in size to methane

Membranes

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Solution-diffusion through a non-porous membrane

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CO2 permeates quickly and pass through the membrane. Methane permeates slowly and bypasses the membrane.

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Single stage can have high purity or high recoverability, but not both

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Multiple-stage design combinations to achieve purity specification at acceptable recoverability

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Does not remove oxygen or nitrogen, but does remove H2S

Nitrogen Removal

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

Altamont LFG to LNG

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

Economics

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Capital cost is $2500 to $4000 per scfm of LFG.

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Most projects require 1500 to 3000 scfm of LFG

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Total costs range from $5 million to $20 million depending on size, LFG quality, nitrogen removal, liquefaction for LNG

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WM’s cost for Altamont LNG plant was $15.5 Mil.

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Production cost is in the $4 to $7 per mmbtu

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Equates to about $0.60 to $1.00 per DEG

Barriers to LFG to CNG/LNG Development

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LFG quality specs conflict with LFG collection system operations

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Cost to produce is about $4 to $7 per mmbtu, about the same or more than natural gas: why invest the capital?

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Most incentives for LFG are targeted to electricity

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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.

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Most areas do not have widespread use of CNG/LNG vehicles or fueling stations

Considerations for Development

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