US DOE Clean Cities Waste-to-Wheels: Building for Success

Erik NeandrossGladstein Neandross and Associates

Promise and Challenge of Renewable Natural Gas as a Vehicle Fuel

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Gladstein Neandross and AssociatesDecember 1, 2010

Natural Gas as a Vehicle Fuel

Biogas: Medium Btu, Methane-Rich Gas Generally Produced by Anaerobic Digestion

Biomethane: Pipeline quality natural gas produced by purifying biogas

LandfillsLandfills Animal waste Wastewater Food waste Industrial

waste sources

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Biogas Produced in Landfills = Landfill Gas (LFG)

• US EPA Landfill Methane Outreach Program (LMOP) tracks landfill gas to energy (LFGE)• ~1754 “active” landfills in US: ~1040 candidate LFGE sites• ~1754 active landfills in US: ~1040 candidate LFGE sites • Operational LFGE sites are well dispersed

geographically• Rule of thumb: one ton landfilled MSW

generate 200 SCF LFG per year• Recovered LFG is typically ~50%

methane (500-600 BTU/SCF) G t t t it ti l dfill• Greatest opportunity: active landfillsclose to markets with > 2 million tons in place in place

• Majority projects in US produce electricity (72%)

• A handful of transportation projectsare operational or under construction

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Operating LFGE Projects (Oct 2010)

Biogas Produced in Wastewater Treatment (WWT) Plants = Digester Gas

• USEPA/USDOE Combined Heat & Power (CHP) partnership tracks WWT projects th t di t t d l t i it it h tithat use digester gas to produce electricity or onsite heating

• 16,000 wastewater treatment (WWT) plants in US • Like landfills, WWT sites tend to be near population centers

Rules of thumb: 100 gal of wastewater generate 1 SCF of digester gas per day;• Rules of thumb: 100 gal of wastewater generate 1 SCF of digester gas per day;100 gal of wastewater generated per person/day

• Recovered WWTP digester gas is typically 60+% methane (550-600 BTU/SCF)

• 544 WWTPs > 5 million gallons/day have digesters • 76 of those use digester gas for onsite and/or

offsite energy needs • WWTP digesters can co-digest wastes from other

sources: e.g., food waste, industrial waste, etc.• One project uses recovered gas for

transportation (Flint)

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Biogas Produced from Animal Waste = Digester Gas

• USEPA/USDA/USDOE AgSTAR program tracks energy projects at commercial livestock farms• 7000+ large-scale dairy, poultry, beef and swine farms in US • Many states have potential sites (dairy in Midwest, Northeast and West; swine in South and

Northeast, poultry in South and Midwest)• Rule of Thumb: 1 lb of manure generate

1 SCF of digester gas per day g g p y• Digester gas is typically 55-65%

methane (600 BTU/SCF)• As of Nov. 2010, AgSTAR estimates

160 it h di t i l160 sites have digesters in place• Most use recovered gas to generate

electricity; several inject gas to pipeline• One project currently uses recoveredOne project currently uses recovered

gas for transportation (Hillarides);another is under developmentwith Clean Cities support Operating Anaerobic Digester Projects (Nov 2010)

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From “Waste” to Wheels, Biogas Must Be Upgraded to Renewable Natural Gas

NATURAL GAS PIPELINE

PipelineFOOD WASTE Adapted from K. Sorchek, Xebec,Inc. Biogas USA, Oct. 2010.

R bl N t l G (RNG) Bi th

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Renewable Natural Gas (RNG) = Biomethane

Upgrading Biogas to RNG Adds Complexity and Cost

Biogas Requires More Purification than Natural Gas from Most Fossil Sources

Parameter Unit EU LFG EU AD-Biogas NA NG NNA NG Pipeline

NG in US

Source (Persson 2006) (Segeler 1965)

All gas requires purification Biogas purification

reduces H2S, oxygen, Source (Persson 2006) (Segeler 1965)

LHV: avg.range Btu/ft3 406 584 1081

835–13361145

627–17171049

945–1121

CH4: avg.range vol % 45

36–6563

53–7051.5

84.7–98.877.0

22.8–98.089.4

72.8–95.2

reduces H2S, oxygen, CO2, N2 and various contaminants Biogas purification on

smaller scale (thusCO2: avg.

range vol % 4015–50

4730–47

0.550–6.0

4.10–29.0

0.70–2.0

N2: avg.range vol % 15

5–400.2–

4.030–29.4

1.70–12.1

2.90–17.1

O : avg 1 0 0 06 0 1 0 0

smaller scale (thus more costly) than fossil NG Combustion engines

( hi l ) d ’ O2: avg.range vol % 1

0–50–

0.060–0.4

0.10–1.4

0.00–0.4

H2S: avg.range ppmv <100

0–100<1000

0-10000100

0–3100400

0–5200 –

NH3 ppm 5 <100 – – –

(vehicles, gensets) don’t need pipeline grade NG, but do need >90% CH4& siloxane removal

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Lack of Vehicles and Infrastructure Have Constrained Market Penetration

Potential markets for RNG– Like fossil natural gas, nearby fleets

seeking price stability (long-term fixed price contracts) • Refuse trucks (garbage, recycling and e use uc s (ga bage, ecyc g a d

transfer trucks)• Milk trucks• Other local users (taxi, municipal

)vehicles, etc.)

– LNG production plant for more regional fleet useG tiliti di t t t ( i– Gas utilities, distant customers (via pipeline injection)

RNG projects often can produce more

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p j pfuel than available fleets can consume

Yet as a Vehicle Fuel, RNG Has Significant Benefits

RNG Has Significant Carbon Benefits Beyond Conventional NG

Depends on reference case (flaring versus venting) Flaring is good, reducing impact of carbon by factor of 8 Energy recovery is better (renewable energy qualifies for state

Renewable Portfolio Standards)

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Renewable Portfolio Standards) RNG is better still, reducing greenhouse gases by 75-90%, or more.

Biomethane Potential

1998 DOE Study: “Biogas For Transportation Use: A 1998 Perspective,” In the U.S., feasible to capture and use about 1.25 quadrillion BtuIn the U.S., feasible to capture and use about 1.25 quadrillion Btu

from landfills, animal waste and sewage alone This is equivalent to 6 percent of all natural gas used in the U.S.

If all used in transportation it would displace 10 billion If all used in transportation, it would displace 10 billion gallons of gasoline per year.

Potential for cellulosic biomethane is almost unlimited E ( i ll S d ) i l di h Europe (especially Sweden) is leading the way: Sweden’s goal: to displace all natural gas use with biomethane

and all diesel with renewable fuels, including biomethane European studies conclude that cellulosic biomethane production is

far more energy efficient and less costly than any other cellulosic energy - today

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