"You need to look at the
full cycle of solid waste
management...you send
the trucks out to collect
the trash, bring it to
the landfill, and,
ultimately, the trash,
as it decomposes,
provides the fuel for
the trash itself."
Robert Ferrier
Deputy Director of the Environmental
Services Department
City of San Diego
Greenhouse Gas Emissions
from Waste Management (1997)'
Collection and Recycling
Transportation
' Negative emissions indicate net carbon storage.
Source: IWSA draft report, "The Impact of Municipal Solid Waste
Management on Greenhouse Gas Emissions in the United States."
Greenhouse gas emissions from the collection and transportation
of waste and recyclables equaled 918,000 metric tons of carbon
equivalent (MICE) in 1997—accounting for 9 percent of the total
net greenhouse gas emissions from waste management that year.
These emissions result largely from the combustion of diesel in
vehicles that transport mixed waste and recyclables from the
waste source to transfer, disposal, or recovery facilities.
Clean Energy Transportation
Innovative waste management programs have proven that route optimization
and the conversion of landfill gas to liquefied natural gas (LNG) for use as
vehicle fuel can substantially curb greenhouse gas emissions. Route optimiza-
tion aims to decrease travel distance, and, thus, reduce fuel consumption.
Alternatively, the use of LNG directly targets the source by replacing diesel
with a clean burning alternative fuel. The City of San Diego, a ClimateWise
participant publicly committed to reducing greenhouse gas emissions, has
implemented several cutting-edge programs with these aims.
Route Optimization
Improving collection efficiency by optimizing routes can significantly reduce
vehicle fuel consumption and collection costs associated with solid waste
management. Fuel consumption is on the rise because more trucks and collec-
tion loops are needed to pick up increasing quantities of waste and recy-
clables. These effects are exacerbated by reliance on inefficient
collection routes. In turn, increased fuel consumption will lead
to increased greenhouse gas emissions and higher costs.
A study undertaken by the Solid Waste Association of North
America found that collection costs typically represent the sin-
gle largest percentage of MSW management budgets, comprising
39 percent to 62 percent of total system costs.
Cities can reduce greenhouse gas emissions and improve the
system's cost effectiveness by designing compact collection
routes, equalizing workloads between different routes, minimiz-
ing the distance traveled from the unloading site, and consider-
ing traffic patterns along the route. Computer technologies
such as Geographic Information System street maps and cus-
tomer databases are now available to ease the arduous task of
manually re-routing collection vehicles.
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Switching from
Diesel to Landfill-
Derived Fuel
Using landfill methane to fuel col-
lection vehicles reduces the con-
sumption of diesel fuel, the major
source of waste-related transporta-
tion emissions. Landfills emit
methane, a greenhouse gas, due to
the anaerobic decomposition of
municipal solid waste. Recent tech-
nological advances have made it
possible to collect this landfill gas
and process it into clean burning
liquefied natural gas (LNG).
The City of San Diego, in a 1997
agreement with Clean Air Partners,
committed to converting 54 heavy-
duty refuse collection trucks to dual
fuel LNG-Diesel engines. The city's
waste managers viewed the conver-
sion of landfill gas to LNG as an
opportunity to fulfill this commit-
ment and "close the loop" by using
waste to generate the fuel used to
collect more waste.
San Diego entered into a public-pri-
vate partnership with Applied LNG
Technologies USA (ALT) to produce
LNG from landfill gas at an existing
city landfill. ALT is developing a LNG
fueling facility capable of producing
3,000 gallons of LNG per day.
Benefits
Route optimization can significantly
reduce vehicle miles traveled and,
correspondingly, fuel use, green-
house gas emissions, and collection
costs. Efforts in San Diego have
saved an estimated 23,000 miles per
year, or nearly 70,000 gallons of
fuel, which reduces emissions of car-
bon dioxide by 788 tons.
Although San Diego has not estimat-
ed cost savings associated with
improved routing, a 1999 EPA study
found that improved routing in
selected cities led to annual savings
ranging from $26,500 - $452,000.
Decreasing the use of diesel fuel
further reduces greenhouse gas
emissions. Harvesting landfill gas
lowers emissions by diverting
methane from entering the atmos-
phere. In addition, using LNG
reduces greenhouse gas emissions
that would have been emitted by
diesel vehicles. The City of San
Diego projects that the fleet conver-
sion will reduce diesel fuel consump-
tion by 561,600 gallons per year,
which equates to emissions reduc-
tions of 1,800 tons of carbon diox-
ide per year.
The City of San Diego expects that the
reduced cost of LNG fuel will offset
the additional costs of fueling sta-
tions. Projections based on the cur-
rent cost of diesel at $1.47 per gallon
indicate that fuel cost savings will be
$220,000 during the first year of
operation. These savings more than
offset the $135,000 it takes to lease
the LNG fueling station. As diesel
prices continue to rise and additional
LNG vehicles are added to the collec-
tion fleet, fuel cost savings are
expected to further increase.
Landfill gas conversion projects may
prove particularly beneficial in
municipalities with small landfills.
At landfills where the absence of an
adjacent power facility makes
regeneration problematic, a LNG
fueling facility and storage tanks
would provide fuel for the local fleet
and the option of shipping any
additional fuel for sale elsewhere.
Challenges
The start-up costs involved in
efforts to optimize routes and/or
establish a program to convert land-
fill gas to LNG fuel can be consider-
able. However, later economic bene-
fits can offset an initial investment
in computer-assisted routing or col-
lection system analysis.
The City of San Diego overcame cost
barriers by partnering with a private
technology provider that was willing
to take the risk of investing in a
cutting-edge technology. The part-
nership with ALT guarantees a five-
year supply of LNG at a fixed price
and a LNG expert to operate and
oversee the facility. Other munici-
palities similarly reluctant to spend
public money on research and devel-
opment projects could consider con-
tracting with a private LNG provider.
Additional
Information
Robert Ferrier, Environmental
Services Department, City of San
Diego, email: rjf@sannet.gov;
http://www.sannet.gov/
environmental-services/
EPA Office of Solid Waste and
Emergency Response, MSW
management:
http://www.epa.gov/epaoswer/non-
hw/muncpl/coll-eff/
EPA's Climate and Waste Program increases
awareness of climate change and its link to
waste management in order to (1) make
greenhouse gas emissions a factor in waste
management decisions and (2) employ waste
management as a mitigation action for reduc-
ing greenhouse gas emissions. For additional
information on EPA's Climate and Waste
Program, see www.epa.gov/mswclimate.
Solid Waste and
Emergency Response
(5306W)
W I
EPA 530-F-02-020
July 2002
www.epa.gov
Recycled/Recyclable
Printed with Vegtable Oil-Based Inks
on Recycled Paper
(Minimum 50% Postconsumer)
Process Chlorine Free
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