Great overview of RNG looking at entire U.S. and resources and opportunities.

1. US DOE Clean Cities
Waste-to-Wheels: Building for Success
Erik Neandross
Gladstein Neandross and Associates
Promise and Challenge of Renewable
Natural Gas as a Vehicle Fuel
Clean Cities / 1
Gladstein Neandross and Associates
December 1, 2010
Natural Gas as a Vehicle Fuel

2. 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
Clean Cities / 2

3. 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 landfills
close to markets with > 2 million tons in place
in place
• Majority projects in US produce
electricity (72%)
• A handful of transportation projects
are operational or under construction
Clean Cities / 3
Operating LFGE Projects (Oct 2010)

4. 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)
Clean Cities / 4

5. 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 dayg 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 development
with Clean Cities support Operating Anaerobic Digester Projects (Nov 2010)
Clean Cities / 5

6. 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
Clean Cities / 6
Renewable Natural Gas (RNG) = Biomethane

7. 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
835–1336
1145
627–1717
1049
945–1121
CH4: avg.
range
vol %
45
36–65
63
53–70
51.5
84.7–98.8
77.0
22.8–98.0
89.4
72.8–95.2
reduces H2S, oxygen,
CO2, N2 and various
contaminants
 Biogas purification on
smaller scale (thus CO2: avg.
range
vol %
40
15–50
47
30–47
0.55
0–6.0
4.1
0–29.0
0.7
0–2.0
N2: avg.
range
vol %
15
5–40
0.2
–
4.03
0–29.4
1.7
0–12.1
2.9
0–17.1
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
0–5
0
–
0.06
0–0.4
0.1
0–1.4
0.0
0–0.4
H2S: avg.
range
ppmv
<100
0–100
<1000
0-10000
100
0–3100
400
0–5200
–
NH3 ppm 5 <100 – – –
(vehicles, gensets) don’t
need pipeline grade NG,
but do need >90% CH4
& siloxane removal
Clean Cities / 7

8. 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 ande 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 use
G tiliti di t t t ( i– Gas utilities, distant customers (via
pipeline injection)
RNG projects often can produce more
Clean Cities / 8
p j p
fuel than available fleets can
consume

9. 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)
Clean Cities / 9
Renewable Portfolio Standards)
 RNG is better still, reducing greenhouse gases by 75-90%, or more.

10. 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
Clean Cities / 10