waste management ottawa renewable energy workshop west carleton environmental centre april 8, 2011

Waste Management

Ottawa Renewable Energy Workshop

West Carleton Environmental Centre

April 8, 2011

• Natural anaerobic decomposition of organic waste in the Natural anaerobic decomposition of organic waste in the landfilllandfill

• Landfill gas is about 50% methane when it is producedLandfill gas is about 50% methane when it is produced

• Methane is the fossil fuel component of natural gasMethane is the fossil fuel component of natural gas

Landfill Gas: A Renewable Resource

©2011 Waste Management

Any technology or Any technology or applicationapplication

that uses natural gasthat uses natural gas

can also use landfill gascan also use landfill gas

Landfill Gas Collection

Fifth level 18pt Trebuchet


< Perforated pipe wells are drilled into < Perforated pipe wells are drilled into the waste, about one every 50 metersthe waste, about one every 50 meters

< The wells are connected to < The wells are connected to a header pipe. A blower a header pipe. A blower places a vacuum on the places a vacuum on the header pipe to withdraw the header pipe to withdraw the gas.gas.

< If it is not < If it is not used as fuel used as fuel for a beneficial for a beneficial use, the gas is use, the gas is simply burned simply burned off in a flareoff in a flare

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

Industrial Fuel (“Medium Btu”) Industrial Fuel (“Medium Btu”) – about 20%– about 20%Use in lieu of fossil fuel in steam boilers, cement kilns, heating, Use in lieu of fossil fuel in steam boilers, cement kilns, heating, leachate evaporation, greenhouses, etc.leachate evaporation, greenhouses, etc.

Natural Gas (“High Btu”)Natural Gas (“High Btu”) – about 5% (25 – about 5% (25++))Clean to natural gas specifications, compress, and insert into Clean to natural gas specifications, compress, and insert into a natural gas pipelinea natural gas pipeline

LNG/CNG Vehicle FuelLNG/CNG Vehicle Fuel – 3 – 3Clean to fuel specifications, compress or liquefy, and store in Clean to fuel specifications, compress or liquefy, and store in on-site fueling station or haul to off-site fueling stationon-site fueling station or haul to off-site fueling station

Types of Landfill Gas Projects


Year No. Year No.

1982 1 2007 3

1986 2 2008 3

2001 2 2009 6

2003 1 2010 2

2004 2 2011 YTD 1

2006 2

LFG to Pipeline Quality – Project History


Location Type Developer Output/Day Start Status

Puente Hills, CA CNG LA County 1,000 GEG 1993 ?

Bowerman, CA LNG Prometheus 5,000 LNG Gal2006Inactive

Sonoma Co., CA CNG SCS Energy 500+ GEG 2008 Pilot

Columbus, OHCNG FirmGreen 700 GEG 2008Inactive

Altamont, CA LNG Linde/WM 13,000 LNG Gal 2009Active

Dane Co., WI CNG Shaw 100 GEG 2011Active

Known LFG to LNG/CNG Projects


Typical Ranges

•Methane 45% - 55%

•CO2 35% - 45%

•Nitrogen 4% - 12%

•Oxygen 0.2% - 3%

•Moisture 4% - 6%

•H2S 20 - >1,000 ppm

•Siloxane 5 – 200 mg/m3

•NMOCs 20 – 500 ppm

Landfill Gas Constituents


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

Product Specifications


Constituent

LFG NG CNG Fuel LNG Fuel

Methane 45 – 55% > 96% > 88% > 96%

CO2 35 – 45%< 5% < 5%

< 50 ppm

<5%Nitrogen 4 – 12%

Oxygen 0.2 – 3%< 0.2 – 0.4%

< 1% < 0.1%

H2S20 - >1000

ppm< 4 ppm < 16 ppm < 16 ppm

Siloxanes5 – 200 mg/m3

ND to No Spec

ND ND

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


•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


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


•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


•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


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


MOLECULAR SIEVEMOLECULAR SIEVE

SULFUR TREATSULFUR TREAT

MEMBRANE SKIDMEMBRANE SKID

LIQUEFACTIONLIQUEFACTION

LNG STORAGE LNG STORAGE

Altamont LFG to LNG

CH4 = 46%CH4 = 46%

N2 = 12%N2 = 12%

CO2 = 37%CO2 = 37%

O2 = 1.3%O2 = 1.3%

H2S = 100 ppmH2S = 100 ppm

H2O = 3.4%H2O = 3.4%

VOC = 0.3%VOC = 0.3%

High BTU FuelHigh BTU Fuel

> 96% Methane> 96% Methane

•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


•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


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


waste management ottawa renewable energy workshop west carleton environmental centre april 8, 2011

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