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www.jacobs.com | worldwide
Estimating GHG Impacts
for Residential Waste
Management Programs
Presented by Doug Huxley
Climate Change Practice Leader
At the SWANA Western
Regional Symposium
April 9, 2019
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Disclaimer
The material in this presentation has been prepared by Jacobs Engineering Group
Copyright and other intellectual property rights in this presentation vest exclusively with Jacobs. Apart from any use
permitted under applicable copyright legislation, no part of this work may in any form or by any means (electronic,
graphic, mechanical, photocopying recording or otherwise) be reproduced, copied, stored in a retrieval system or
transmitted without prior permission.
© Copyright
February 27, 2019
Jacobs Engineering Group. All rights reserved.
Image by Markus Distelrath from Pixabay
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Thousands of cities and
counties have pledged action
Aspirational targets,
often with no solid plan
Responsibilities with
multiple departments
Uncertainty with limited
understanding of benefits,
costs, and risks
Solid waste GHG reductions
mandated in California
Challenges facing local governments
We Are Still In
America’s Pledge
Global Covenant of Mayors
California SB1383
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80% Targets Require Action Across All Sectors
To view the full documents, visit https://ghgprotocol.org/public-sector-protocol-0
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Need common platform for
analysis of benefits
Typically compares against
zero, versus true baseline
Scope 1, 2, and 3 focus means
secondary impacts often
ignored
Annual focus, vs. solid waste
life cycle
Only used in corporate and
muni protocols
Limitations of Corporate Accounting for evaluating mitigation options
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Project based accounting approach
Figure from GHG Protocol Project Accounting Standard, P. 13
Baseline scenario: absolutely required for meaningful evaluation of change
Evaluate all impacted GHG emission sources, regardless of ownership and control
Yearly updates are usually to include updated information for life of project, not to indicate annual performance
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Project based accounting approach Key Concepts
1
2
3
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Example GHG Profile Landfill Future Growth
Profile shows the change at
this landfill but is incomplete
picture of city-wide baseline.
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Example GHG Profile Food Waste Diversion
Profile includes landfill and
digestion benefits and is
more consistent with
city-wide baseline since it
incorporates growth.
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Example GHG Profile City-wide waste management
Profile includes city-wide
emissions, but evaluation
of LFGTE and recycling
benefits still requires
evaluation of impacts
outside city Scope 1, 2,
and 3 footprint
Baseline is not zero
Baseline is dynamic
GHG emission increases / decreases vary by year
Boundary definition must match the question at hand
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Example GHG Profile Concepts
1
2
3
4
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Existing tools for solid waste GHG analyses
WARM (USEPA Waste Reduction Model)
– EPA model built in 1998, now V14
– Life cycle GHG comparative evaluation
– Good tool for general comparison of alternatives, however:
• Hard to customize for multiple transportation steps, alternative fuels, capture rates, etc.
• Only one option for use of biogas, displacement of grid power
• Black box makes it hard to understand where benefits or emissions occur
• Discrepancies exist between guidance and model
LandGem
– EPA model and accepted standard for landfill gas production
– Good tool for landfill gas flows, poor tool for GHG impacts of alternatives
Landfill
Dry digestion
Wet digestion
Wet digestion –
headworks
Composting
Chip & grind
Recycling
Transportation
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GHG Calculator - Processes Included Flow diagram #3 of 5 from LASAN model
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GHG Calculator – transparent and customizable
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Ability to specify haul
distances including
intermediates and residuals
Consideration of
CNG and RNG
Functionality for food waste to
WWTP headworks
Ability to specify average gas
collection efficiency
Definition of benefits of landfill
& digester biogas use besides
grid electricity displacement
Good basis for demonstration
of SB1383 emissions
reductions
GHG Calculator
Transportation is small impact compared to other
categories
CNG fuel a relatively small difference vs. diesel on
a life cycle or tailpipe basis
Benefits of alternatives highly sensitive to gas
collection efficiency and landfill moisture
Food waste - big benefit to digestion vs. landfill
– Gas capture higher in digester
– Low landfill carbon storage
Yard Waste - small benefit to digestion vs. landfill
– Slower decay rate, less landfill gas
– Higher carbon storage
Soil and landfill carbon storage are important in
considering reduced biogenic emissions
Recycling benefits dwarf other categories (if
recyclables are really recycled!)
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Lessons learned - examples
Reduction targets of 80-100% require action
across all sectors
Actions must be evaluated against future baseline
to be meaningful
WARM is useful in understanding life cycle
impacts, but limited
Customized GHG calculator allows a city-specific,
comprehensive planning view
GHG impacts that occur outside system
boundaries (e.g., LFGTE) are accounted for as
“negative” emissions
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Summary
Doug Huxley Golan Kedan 1.720.286.5503 1.206.234.6524
[email protected] [email protected]
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Thank You
Thanks to: Jeremy Pathmanabhan, and his
team at LA Sanitation & Environment