HomeMy WebLinkAbout~Master - November 16, 2021, Special Meeting of the Ames City Council
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MEMO
To: Mayor and City Council
From: Deb Schildroth, Assistant City Manager
Date: November 12, 2021
Subject: Objectives for the Second Climate Action Plan Steering Committee Meeting
The objectives for this CAP workshop is to inform the Steering Committee about the
Business As Usual (BAU) results, engagement outputs to date, and target-setting
approaches developed by SSG. While there will be no decision making required at this
meeting, questions, concerns, and comments presented by the Steering Committee will be
addressed.
The materials to be reviewed during this meeting include the BAU results summary,
target setting briefing, and carbon budget briefing.
BUSINESS AS USUAL
SUMMARY
Prepared for the Ames Climate Action Plan
October 2021
Disclaimer Reasonable skill, care and diligence has been exercised to assess
the information acquired during the preparation of this analysis,
but no guarantees or warranties are made regarding the
accuracy or completeness of this information. This document, the
information it contains, the information and basis on which it
relies, and factors associated are subject to changes that are
beyond the control of the author. The information provided by
others are believed to be accurate but have not been verified.
This analysis includes strategic-level estimates of costs and
revenues that should not be relied upon for design or other
purposes without verification. The authors do not accept
responsibility for the use of this analysis for any purpose other
than that stated above and does not accept responsibility to any
third party for the use, in whole or in part, of the contents of this
document. This analysis applies to Ames and cannot
be applied to other jurisdictions without analysis. Any use by the
Ames, its sub-consultants or any third party, or any
reliance on or decisions based on this document, are the
responsibility of the user or third party.
2
Contents
3
Community
Energy
Consumption
Community
GHG
Emissions
Energy &
Emissions by
Sector
BAU Summary
& Trend
Analysis
Appendix A:
Technical
Information
Appendix B:
Energy and
Emissions
Tables
Introducing
Ames
Developing a
business-as
-usual (BAU)
scenario
SECTION ONE
An Introduction to Ames
4
About Ames
5
Ames is a small but growing city with a
population of around 66,000 people. It is
home to Iowa State University (ISU) and
a student population that makes up half
of the city’s population.
Unlike many small cities, the City of
Ames owns its own electrical utility that
supplies part of Ames’ electricity. . This
has allowed the City to decrease
emissions already and is an area of
opportunity for future emissions
reductions.
Likewise, improvements to ISU’s central
heating plant will reduce emissions and
is an area for future opportunity.
Local control over a significant portion of energy production and distribution is a rare circumstance and opportunity. The City of Ames and ISU are already taking advantage of their ownership of energy assets in the community to reduce emissions. Opportunities exist to build on their respective successes but this does not negate the need for other emissions reductions actions in the community.
Community Demographics
6
Demographics are an important consideration
when thinking about future energy use and
emissions.
It can be helpful to understand if energy and
emissions are increasing or decreasing per capita
over time and/or as a result of population and
employment growth over time.
In Ames, the City expects the following growth
trends between 2018 and 2050:
●44% growth in employment
●23% growth in the number of households
●24% growth in the number of vehicles
●33% growth in population
SECTION TWO
Developing a Business-as-Usual
Scenario
7
What is a BAU?
8
The business-as-usual (BAU) scenario
detailed in this document is a projection
of energy use and GHG emissions in
Ames in 2050, should the community
continue on its current course of action.
The BAU assumes no additional policies,
actions, or strategies are implemented
by 2050 beyond those that are currently
approved and funded or underway.
This document highlights major trends from the BAU results and is not a comprehensive summary of all factors that contribute to energy and emissions patterns over the timeframe.
The BAU scenario uses a 2018 baseline in line with the last census year. Aligning the baseline with a census year allows us to
use the most accurate and comprehensive data available for our analysis.
Future scenarios
A scenario is an internally consistent view of
what the future might turn out to be. It is not a
forecast, but one possible future outcome that
is based on currently available information.
Business-as-Planned Scenario
Assumptions
Analysis and
interpretation of data
and information
Data and Information
Data from the City &
other trusted sources
Policies and plans
approved and/or
underway
Projections
Projections for individual factors
modeled together to forecast a future
plausible scenario for community
energy-use and emissions
Two steps were taken to develop
and quantify the BAU Scenario:
A full Data, Methods, and Assumptions Manual for the project is available at cityofames.org/sustainability
Key Assumptions in the BAU Scenario
Heating Degree
Days
Grid-carbon intensity Building Efficiency Increase in EVs
Declining Stable Increasing Increasing
As the climate warms there
will be a lesser need for home
heating in Ames but a greater
need for home cooling.
Grid-carbon intensity
(emissions from grid
electricity) will remain similar
to current levels, except where
noted in the BAU.
As the population grows and
new homes are built, a
greater proportion of homes
in Ames will meet current
building code requirements.
EV purchases will increase in
line with federal targets,
reaching 50% of vehicles sales
by 2030.
SECTION THREE
Community Energy Consumption
12
Energy & Emissions Source Descriptions
Ames has a unique combination
of energy sources. Locally,
energy is produced via
individual solar PV installations
and through ISU’s district energy
(combined heat and power)
system. Grid electricity comes
from four sources, including the
City of Ames’ own electrical
utility.
Legend Description
Local energy Solar PV
RNG Renewable natural gas
Fuel oil, propane,
natural gas
Direct to consumer (residential,
commercial, industrial)
District energy ISU combined heat and power (CHP)
system
Grid electricity From all utility providers
Fugitive Emissions from the production and
transportation of natural gas
13
Grid Electricity Supply by Utility & Fuel Type
There are four separate utilities
that provide electricity to Ames’
residents and businesses. Each
of the utilities derive their
electricity supply from different
fuel sources.
14
Grid Emissions Factor for Ames in 2018
The different fuel sources used
by each utility results in
different grid emissions factors
(which represents the amount
of greenhouse gas emissions
emitted) for each utility. Each
utility also provides a different
amount of electricity to Ames.
We consider both of these
aspects when calculating the
overall emissions factor for
electricity in Ames.
15
Figure 1
Projected total community energy use,
2018-2050
16
17
1
2
3
Community Energy Use
Total energy consumption in 2050 is projected to be
approximately the same as in the 2018 baseline
year, at 1.2 million MMBTUs
Transportation energy use will decrease with electric
vehicle sales displacing some gasoline-fueled vehicles.
Energy use in all other sectors will increase as the
population grows and services and employment grow
alongside population growth.
18
1
2
3
Figure 2
Projected community energy use by end
use, 2018-2050
19
20
1
2
3
Community Energy Use by End Use
Toward 2050, transportation remains the most
energy intensive activity in the community despite an
overall decrease in the energy consumed for this end
use.
Energy use for space heating and other
buildings-related end uses increase over the
projection period as population and employment grow.
Energy use for industrial processes increases,
reflecting employment growth in the sector.
21
1
2
3
Figure 3
Projected community energy use by fuel
type, 2018-2050
22
23
1
2
3
Ames is powered mostly by natural gas in 2018 and this
will remain true through to 2050 due to population growth
and the conversion of Iowa State University’s energy
system from coal to natural gas.
Grid electricity use will increase significantly between
2018 and 2050, outpacing increases in natural gas usage.
This is due to population growth and a switch to electric
vehicles.
Gasoline use in the community is halved between 2018
and 2050 due to the uptake in electric vehicles.
Community Energy Use by Fuel Type
24
1
2
3
GRAPH 4
Projected community energy use per
capita, 2018-2050
25
26
Per Capita Energy Use
Per capita energy use is anticipated to decline by 33%
between 2018 and 2050.
The decline in energy use is due to increasing energy
efficiency over time including new vehicles and buildings
being more efficient.
Overall community energy use will remain constant,
meaning in 2050 there will be more people in Ames using
the same amount of energy that was used in the
community in 2018.
27
SECTION FOUR
Community Greenhouse Gas Emissions
28
GRAPH 5
Projected total community GHG
emissions, 2018-2050
29
30
1
2
3
Community Emissions
Total annual emissions decrease slightly between 2018 and 2050, from
approximately 1240 ktCO2e to 1180 ktCO2e.
The sharp decrease in commercial and residential emissions in 2019 is due to
the emissions factor of grid electricity decreasing with Ames Electric Service
using the power from their wind turbine to offset their own emissions
rather than selling renewable energy credits (RECs) to other utilities as they did
in 2018.
The sharp decrease in 2024 in energy production is due to the university’s
energy system being converted from coal to natural gas.
Transportation emissions decrease for a period as gasoline use decreases
and electricity use in the sector increases. Later, emissions begin to increase
again as usage outpaces the emissions reductions from low emissions vehicles.31
1
2
3
GRAPH 6
Projected community emissions by
source, 2018-2050
32
33
1
2
3
Community Emissions by Source
In 2019, the impact of REC purchases can be seen on grid electricity
emissions. The emissions from the grid begin to increase again over time
as the use of electricity in Ames increases with population growth.
Emissions from natural gas increase in 2024 as coal emissions are eliminated.
Emissions from natural gas continue to increase gradually beyond 2024
as the population grows and use increases.
Gasoline and diesel emissions decrease while all others sources increase
with population growth.
34
1
2
3
GRAPH 7
Projected community emissions per
capita, 2018-2050
35
36
Community Emission Per Capita
Per capita emissions are anticipated to
decline from 18.8 tonnes per person in 2018
to 13.4 tonnes per person in 2050 (-29%).
There is a wide range of per capita emissions
in municipalities with fewer than 100,000
residents in the midwestern United States, as
outlined in the table to the left.
According to the latest recommendations from
leading climate science organizations, per
capita emissions in cities in wealthy countries
should be <3 tCO2e by 2030.
City Emissions (tCO2e)
in 2018
Iowa City, Iowa 13.7
Carmel, IN 13.3
Evanston, IL 12.7
Albany, NY 10.1
Medford, MA 8.2
C40 Cities
Average 6.2
Median 5
37
SECTION FIVE
Energy and Emissions by Sector
38
GRAPH 8
Projected buildings energy use,
2018-2050
39
40
Buildings Energy Use by Fuel
Total energy consumption in buildings is projected to rise from around 7.1 million
MMBTU per year in 2018 to around 8.5million MMBTU per year in 2050.
This 19% growth reflects population and employment growth that is tempered by
new buildings being built more efficiently than existing buildings. In other words, the
number of buildings meeting 2012 building codes, which have higher energy efficiency
standards than previous codes, will increase.
Natural gas accounts for nearly half of building energy consumption throughout
the period.
Electricity consumption in buildings increases by roughly 30% with increases in energy
use for space cooling, lighting, major appliances, and plug load as the population
increases.41
GRAPH 9
Projected buildings energy use by
sector, 2018-2050
42
43
Buildings Energy Use
Energy use in buildings increases for all sectors between 2018 and 2050.
Energy use in the industrial sector increases by 50% over the timeframe due to a
projected increase in industrial floorspace.
The increases in energy use in municipal (26%), residential (18%) and commercial (8%)
buildings can be attributed to population and employment growth and growth in
associated community services without additional policies and programs beyond
those currently in place to encourage building efficiencies.
Across all buildings, growth in energy use for space heating is low (2%) and growth in
energy use for space cooling is much higher (29%) due to milder winters and hotter
summers.
44
GRAPH 10
Projected emissions from buildings,
2018-2050
45
46
Building Emissions
Emissions from buildings are projected to increase
from around 5.6 to 5.9 MtCO2e per year by 2050.
Initially emissions from buildings decrease due to the
drop in the grid emissions factor for electricity in 2019.
This efficiency gain is soon overtaken by increased
energy demand in buildings across all sectors and fuel
types.
47
GRAPH 11
Projected transportation energy use,
2018-2050
48
49
Transportation Energy Use
Overall energy use in transportation is projected to decrease by 29% during the
period.
Gas consumption decreases by 53% between 2018 and 2050, reflecting Ames
meeting the federal goal of 50% of vehicles sales being electric by 2030.*
Diesel use decreases by 9% from 2018 levels, reflecting diesel efficiency standards
and the displacement of some diesel vehicles with electric.
Electricity used for transportation increases from near 0% to 21% of the energy
consumption in the sector as electric vehicles become more common.
*Note that the federal standard, if achieved, does not reflect what will happen in each individual
community across the country. Electric vehicle sales may make up 70% of vehicle sales in some
communities and 30% in others. This highlights the need for continued local action to reach this target.
50
GRAPH 12
Projected community transportation
emissions, 2018-2050
51
52
Transportation Emissions
Emissions in the transportation sector are projected to
decrease by 13% between 2018 and 2050
As electric vehicle sales in the car and light duty truck
categories increase over time, emissions decrease
between 2025 and 2040.
As the population increase and vehicle kilometers travelled
per person increases, emissions begin to climb again
around 2040. This increase also reflects the expectation
that there will still be emissions from grid electricity in
2040.
53
GRAPH 13
Projected emissions from waste,
2018-2050
54
55
Waste Emissions
The model uses a first order decay model for waste meaning that it accounts for methane
release from waste over time rather than during the year it was deposited.
In 2018 the Waste to Energy facility underwent a repair and only 30% of waste was
combusted in 2018, ramping back up to 73% by 2021. During this period more waste was
brought to the landfill, resulting in an increase in emissions as that waste decays over time.*
Emissions from waste are anticipated to grow by 91%. as a result of a growing community
without additional plans for increasing diversion rates.
Wastewater emissions are negligible due to a methane capture system in place at the
wastewater treatment facility.
*Emissions from the Waste to Energy facility are captured in the grid electricity emissions factor rather than under
the waste emissions category.
56
SECTION SIX
BAU Summary & Trend Analysis
57
The City’s of Ames projects significant ongoing population growth, reaching over 87,000 by 2050,a 33% increase over the 2018 population. This growth requires rethinking energy systems to accommodate growth while decreasing emissions.
The BAU projections for Ames indicate that emissions will decrease slightly from around 1240 ktCO2e in the 2018 baseline year to around 1176 ktCO2e in 2050. This reflects a period of anticipated employment and population growth that is offset by the phase-out of coal, growth of electrification in the transportation sector, and more efficient buildings.
58
Population and employment growth will influence energy and emissions use in Ames
Out of all fuel sources, grid electricity remains the most significant source of emissions. This highlights an opportunity for the grid to be further decarbonized through the addition of grid-tied and community- scale renewable energy. The City of Ames’ electric utility has already demonstrated the benefit of this action with the addition of wind-source energy that has decreased the emissions factor of the utility’s electricity.
Natural gas use also makes up a significant proportion of Ames’ emissions. Efforts to decarbonize this source or fuel-switch to electricity, which can be decarbonized through an increase in renewables, are key to reducing emissions.
59
Grid-tied renewable energy is an opportunity in Ames, given the City has direct control over one third of the community’s electricity supply through its own utility.
Amongst sectors, transportation is the largest source of emissions between 2018 and 2050 even as emissions in the sector decrease by 13% over the period. This calculation considers federal targets of 50% electric car sales by 2030.
Energy production is also a significant source of emissions although emissions from this source decrease during the projection period. This accounts for the central heating plant at the university and highlights the significant role the university plays in addressing energy and emissions reductions in the community due to its size.
Significant emissions from residential and commercial sectors highlight, once again, the need for renewables at the grid level and fuel-switching.
60
Ames’ emissions come from several sectors that pose unique opportunities and challenges for reducing emissions.
Emissions from waste are captured in two different portions of the BAU. The combustion of waste associated with the waste to energy system is included in the grid emissions factor. Emissions from landfill waste is included in the waste emissions sector.
Solid waste reduction and increased diversion from the landfill are necessary to meaningfully reduce GHG emissions from this growing emissions sector.
A closer look at the waste to energy facility as technology evolves may uncover more efficient processes for waste disposal.
61
Best practices and technologies addressing waste and emissions from waste are evolving at a rapid pace but reducing waste will remain a top priority.
Ames is in the process of setting a target for reducing greenhouse gas emissions. Based on the BAU, Ames would need to shift away from non-renewable natural gas, invest heavily in clean electrification and renewables, shift away from gasoline fueled vehicles, and undertake deep energy efficiency improvements in buildings to realize significant reductions in its current emissions. These changes will require changes in policies, regulations, and programs, the participation of residents and business-owners, and partnership and ongoing coordination with other levels of government, industry, and other emitters.
62
Reducing emissions between now and 2050 will require systems level changes in energy production, distribution, and use.
APPENDIX A
Business as Usual Technical Background
63
Developing a BAU Two steps were taken to develop
and quantify the BAU Scenario:
Data collection: A data request was produced and data was
collected with assistance and input from the City.
Assumptions were identified to supplement any gaps in
available data. A data, methods, and assumptions manual
was produced to ensure transparency about the data and
assumptions used.
Model calibration and baseline: The model is custom built
for the local context and includes data for: population,
population assignment to dwellings, jobs assignment to
buildings, a surface model of buildings, transportation, waste,
industry, and land-use. The baseline energy and emissions
inventory year is 2018. The modeling process involves regular
validation of observed data against broader state averages at
each modeling stage.
64
Units of Measurement in this Analysis
65
GHG emissions
1 ktCO2e =
1,000 tCO2e
One kilotonne (kt) of
carbon dioxide
equivalents (CO2e) is
equal to one thousand
tonnes of CO2e.
Energy
1 MMBTU =
1 thousand BTUs
One thousand metric
millions of British
Thermal Units (MMBTU)
is equal to one billion
BTUs.
Emissions are characterized as kilotonnes of
carbon dioxide equivalent (ktCO2e). To compare
fuels on an equivalent basis, all energy is reported
as units of energy content primarily as thousands
of Metric Million British Thermal Units (MMBTU).
These measures can be characterized as follows:
●A 1500 square foot house uses about 500
MMBTUs of energy in a year
●One gallon of gasoline provides about 0.12
MMBTU
●One gallon of diesel or heating oil provides
about 0.14 MMBTU
●A terawatt-hour is about 3.4 MMBTU
*Data provided by United States Environmental Protection Agency
APPENDIX B
Energy and Emissions Tables
66
2018 2050
% change
2018-2050
Employment 38,995 56,318 44%
Households 28,164 34,752 23%
Personal
Vehicles 26,088 32,367 24%
Population 65,993 87,770 33%
Community Demographics
67
Total GHG emissions by sector (ktCO2e)
Sector 2018 2018 Share 2050 2050 Share
% change
2018-2050
Commercial 229.0 18%225.9 19%-1%
District Energy (ISU)292.3 24%216.2 18%-26%
Fugitive 5.0 0%7.2 1%43%
Industrial 97.1 8%122.0 10%26%
Municipal 43.6 4%45.4 4%4%
Residential 205.8 17%201.6 17%-2%
Transportation 331.2 27%287.9 24%-13%
Waste 36.7 3%70.1 6%91%
TOTAL 1240.7 100%1176.3 100%-5%68
Total GHG emissions by fuel type (ktCO2e)
Fuel Type 2018 2018 Share 2050 2050 Share % change 2018-2050
Coal 150.9 12%0.0 0%-100%
Diesel 71.8 6%65.2 6%-9%
Fuel Oil 2.0 0%2.3 0%18%
Gasoline 257.1 21%121.3 10%-53%
Grid Electricity 453.6 37%533.9 45%18%
Jet Fuel 2.1 0%2.7 0%32%
Natural Gas 258.2 21%369.0 31%43%
Non Energy 41.7 3%77.3 7%85%
Propane 3.3 0%4.6 0%40%
TOTAL 1240.7 100%1176.3 100%-5%69
Total GHG emissions (MtCO2e)Total GHG emissions per capita (tCO2e)
2016 2050 % change, 2016-2050
18.8 13.4 -29%
70
Total energy consumption by sector (MMBTU, thousands)
Sector 2018 2018 Share 2050 2050 Share
% change
2018-2050
Commercial 3,563.2 30%3,857.3 32%8%
Industrial 1,151.9 10%1,739.7 15%51%
Municipal 406.5 3%514.0 4%26%
Residential 2,022.1 17%2,377.1 20%18%
Transportation 4,784.2 40%3,413.7 29%-29%
Total 11927.9 100%11901.8 100%0%
71
Total energy consumption by fuel type (MMBTU, thousands)
Fuel Type 2018 2018 Share 2050 2050 Share % change 2018-2050
Diesel 967.6 8%877.6 7%-9%
District Energy (ISU)1,597.4 13%1,443.3 12%-10%
Fuel Oil 26.4 0%31.1 0%18%
Gasoline 3,646.3 31%1,720.9 14%-53%
Grid Electricity 1,973.5 17%3,279.1 28%66%
Local Energy (Solar PV)2.4 0%4.3 0%81%
Natural Gas 3,351.1 28%4,136.8 35%23%
Other 290.6 2%306.4 3%5%
Propane 53.9 0%75.3 1%40%
RNG 18.7 0%27.0 0%44%
Total 11927.9 100%11901.8 100%0%
Total energy consumption by end use (MMBTU, thousands)
End use 2018 2018 Share 2050 2050 Share
% change
2018-2050
Industrial
Processes 883.9 7%1,330.2 11%50%
Lighting 250.9 2%334.1 3%33%
Major Appliances 209.3 2%258.3 2%23%
Plug Load 768.3 6%965.2 8%26%
Space Cooling 587.4 5%755.9 6%29%
Space Heating 3,416.8 29%3,478.9 29%2%
Transportation 4,784.2 40%3,413.7 29%-29%
Water Heating 1,027.1 9%1,365.6 11%33%
Total 11927.9 100%11901.8 100%0%
Total Energy Use Per Capita
(MMBTU, thousands)
2018 2050 % change, 2018-2050
180.9 135.6 -33%
74
Sector Summary: Buildings Energy Use (MMBTU, thousands)
By End Use 2016 2016 Share 2050 2050 Share
% change
2016-2050
Industrial
Processes 883.9 12%1,330.2 16%50%
Lighting 250.9 4%334.1 4%33%
Major Appliances 209.3 3%258.3 3%23%
Plug Load 768.3 11%965.2 11%26%
Space Cooling 587.4 8%755.9 9%29%
Space Heating 3,416.8 48%3,478.9 41%2%
Water Heating 1,027.1 14%1,365.6 16%33%
Total 7,143.7 100%8,488.1 100%19%75
Sector Summary: Buildings Energy Use (MMBTU, thousands)
By Fuel Type 2018 2018 Share 2050 2050 Share
% change
2018-2050
District Energy
(ISU)1,597.4 22%1,443.3 17%-10%
Fuel Oil 26.4 0%31.1 0%18%
Grid Electricity 1,972.5 28%2,587.1 30%31%
Local Energy
(Solar PV)2.4 0%4.3 0%81%
Natural Gas 3,351.1 47%4,136.8 49%23%
Other 121.4 2%183.3 2%51%
Propane 53.9 1%75.3 1%40%
RNG 18.7 0%27.0 0%44%
Total 7,143.7 100%8,488.1 100%19%76
Sector Summary: Buildings Energy Use (MMBTU, thousands)
By Sector 2018 2018 Share 2050 2050 Share
% change
2018-2050
Commercial 3,563.2 50%3,857.3 45%8%
Industrial 1,151.9 16%1,739.7 20%51%
Municipal 406.5 6%514.0 6%26%
Residential 2,022.1 28%2,377.1 28%18%
Total 7,143.7 100%8,488.1 100%19%
77
Sector Summary: Buildings Emissions (ktCO2e)
By End Use 2018 2018 Share 2050 2050 Share
% change
2018-2050
Industrial
Processes 72.0 13%89.3 15%24%
Lighting 49.9 9%47.6 8%-5%
Major Appliances 38.2 7%34.2 6%-11%
Plug Load 146.4 25%132.5 22%-9%
Space Cooling 35.4 6%41.1 7%16%
Space Heating 170.8 30%172.2 29%1%
Water Heating 62.9 11%78.0 13%24%
Total 576 100%595 100%3%
78
Sector Summary: Buildings Emissions (ktCO2e)
By Fuel Type 2016 2016 Share 2050 2050 Share
% change
2016-2050
Fuel Oil 2.0 0%2.3 0%18%
Grid Electricity 392.7 68%368.8 62%-6%
Natural Gas 177.6 31%219.2 37%23%
Propane 3.3 1%4.6 1%40%
Total 576 100%595 100%3%
79
Sector Summary: Buildings Emissions (ktCO2e)
By Sector 2016 2016 Share 2050 2050 Share
% change
2016-2050
Commercial 229.0 40%225.9 38%-1%
Industrial 97.1 17%122.0 21%26%
Municipal 43.6 8%45.4 8%4%
Residential 205.8 36%201.6 34%-2%
Total 575.5 100%595.0 100%3%
80
Sector Summary: Transportation Energy Use (MMBTU, thousands)
By Vehicle Type 2018 2018 Share 2050 2050 Share
% change
2018-2050
Car 1,947.9 42%891.1 27%-54%
Heavy Truck 767.1 17%736.9 22%-4%
Light Truck 1,848.5 40%1,611.2 49%-13%
Urban Bus 51.4 1%51.4 2%0%
Total 4,614.9 100%3,290.6 100%-29%
81
Sector Summary: Transportation Energy Use (MMBTU, thousands)
By Fuel Type 2018 2018 Share 2050 2050 Share
% change
2018-2050
Diesel 967.6 21%877.6 27%-9%
Gas 3,646.3 79%1,720.9 52%-53%
Grid Electricity 1.0 0%692.1 21%68711%
Total 4,614.9 100%3,290.6 100%-29%
82
Sector Summary: Transportation Emissions (ktCO2e)
83
2018 2018 Share 2050 2050 Share % change
2018-2050
Car 137.8 42%80.4 28%-42%
Heavy Truck 56.6 17%54.4 19%-4%
Light Truck 130.8 40%146.5 51%12%
Urban Bus 3.8 1%3.8 1%0%
Total 329.1 100%285.2 100%-13%
Sector Summary: Transportation Emissions (ktCO2e)
84
2018 2018 Share 2050 2050 Share % change
2018-2050
Diesel 71.8 22%65.2 23%-9%
Gas 257.1 78%121.3 43%-53%
Grid Electricity 0.2 0%98.7 35%49176%
Total 329.1 100%285.2 100%-13%
Sector Summary: Waste GHG Emissions (ktCO2e)
85
2018 2018 Share 2050 2050 Share % change
2018-2050
Biological 0.0 0%0.0 0%33%
Landfill 36.7 100%70.1 100%91%
Wastewater 0.0 0%0.0 0%33%
Total 36.7 100%70.1 100%191%
Ames Climate Action Plan and Target Setting
Data, Methods, and Assumptions (DMA)
Manual
July 2021
Purpose of this Document
This Data, Methods, and Assumptions (DMA) manual details the modeling approach used to
provide community energy and emissions benchmarks and projections while providing a
summary of the data and assumptions used in scenario modeling. The DMA makes the modeling
elements fully transparent and illustrates the scope of data required for future modeling efforts.
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CONTENTS
Glossary 3
Accounting and Reporting Principles 5
Scope 6
Geographic Boundary 6
Time Frame of Assessment 6
Energy and Emissions Structure 7
Emissions Scope 8
Table 1. GPC scope definitions.8
The Model 9
Model Structure 10
Sub-Models 11
Population and Demographics 11
Residential Buildings 11
Non-Residential Buildings 12
Spatial Population and Employment 12
Passenger Transportation 12
Waste and Wastewater 13
Energy Flow and Local Energy Production 13
Finance and Employment 14
Consumption Emissions 14
Model Calibration for Local Context 14
Data Request and Collection 14
Zone System 14
Figure 5. Zone system used in modelling.15
Buildings 15
Residential Buildings 15
Non-Residential Buildings 16
Population and Employment 16
Transportation 17
Waste 17
Data and Assumptions 18
Scenario Development 18
Business-As-Usual Scenario 18
Methodology 18
Low-Carbon Scenario 19
Policies, Actions, and Strategies 19
Methodology 19
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Addressing Uncertainty 20
Appendix 1: GPC Emissions Scope Table for Detailed Model 21
Appendix 2: Building Types in the model 25
Appendix 3: Emissions Factors Used 26
Glossary
BAU Business as usual
CBECS Commercial Buildings Energy Consumption Survey
CHP Combined heat and power
DMA Data, methods, and assumptions manual
GHG Greenhouse gases
GIS Geographic information systems
GPC Global Protocol on Community-Scale GHG Emissions Inventories
IPCC Intergovernmental Panel on Climate Change
VMT Vehicle Miles Travelled
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Accounting and Reporting Principles
The municipal greenhouse gas (GHG) inventory base year development and scenario modeling
approach correlate with the Global Protocol for Community-Scale GHG Emissions Inventories
(GPC).1 The GPC provides a fair and true account of emissions via the following principles:
Relevance:The reported GHG emissions appropriately reflect emissions occurring as a result
of activities and consumption within the City boundary. The inventory will also serve the
decision-making needs of the City, taking into consideration relevant local, state, and national
regulations. Relevance applies when selecting data sources and determining and prioritizing
data collection improvements.
Completeness:All emissions sources within the inventory boundary shall be accounted for
and any exclusions of sources shall be justified and explained.
Consistency:Emissions calculations shall be consistent in approach, boundary, and
methodology.
Transparency:Activity data, emissions sources, emissions factors and accounting
methodologies require adequate documentation and disclosure to enable verification.
Accuracy:The calculation of GHG emissions should not systematically overstate or understate
actual GHG emissions. Accuracy should be enough to give decision makers and the public
reasonable assurance of the integrity of the reported information. Uncertainties in the
quantification process should be reduced to the extent possible and practical.
1 WRI, C40 and ICLEI (2014). Global Protocol for Community-Scale Greenhouse Gas Emissions Inventories. Retrieved
from:https://ghgprotocol.org/sites/default/files/standards/GHGP_GPC_0.pdf .
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Scope
Geographic Boundary
Energy and emissions inventories and modeling for the project will be completed for the City of
Ames’ current boundary (Figure 1) and new growth areas as identified in the Ames Plan 2040 draft
(Figure 2). The land-use and density targets modeled will be in line with what is identified in the
2040 plan.
Figure 1. Current geographical boundary for Ames
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Figure 2. Future geographical boundary for Ames and land-use types in growth areas.
Time Frame of Assessment
The modeling time frame will include years 2018-2050. The year 2018 will be used as the base year
since it aligns with the City’s existing inventory and the latest census, and 2050 is the relevant
target year. Model calibration for the base year uses as much locally observed data as possible.
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Energy and Emissions Structure
The total energy for a community is defined as the sum of the energy from each of the aspects:
EnergyCity= Energytransport + Energybuildings + Energywaste&wastewater
Where:
Energytransport is the movement of goods and people.
Energybuildings is the generation of heating, cooling and electricity.
Energywastegen is energy generated from waste.
The total GHG emissions for a community is defined as the sum from all in-scope emissions
sources:
GHGlanduse =GHGtransport +GHGenergygen +GHGwaste&wastewater+GHGagriculture +GHGforest +GHGlandconvert
Where:
GHGtransport is emissions generated by the movement of goods and people.
GHGenergygen is emissions generated by the generation of heat and electricity.
GHGwaste&wastewater is emissions generated by solid and liquid waste produced.
GHGagriculture is emissions generated by food production.
GHGforest is emissions generated by forested land.
GHGlandconvert is emissions generated by the lands converted from natural to modified conditions.
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Emissions Scope
The inventory will include emissions Scopes 1 and 2, and some aspects of Scope 3, as defined by
GPC (Table 1 and Figure 2). Refer to Appendix 1 of this DMA for a list of included GHG emissions
sources by scope.
Table 1. GPC scope definitions.
Scope Definition
1 All GHG emissions from sources located within the municipal boundary.
2 All GHG emissions occurring from the use of grid-supplied electricity, heat, steam and/or
cooling within the municipal boundary.
3 All other GHG emissions that occur outside the municipal boundary as a result of activities
taking place within the boundary.
Figure 2. Diagram of GPC emissions scopes.
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The Model
The model is an energy, emissions, and finance tool developed by Sustainability Solutions Group
and whatIf? Technologies. The model integrates fuels, sectors, and land-use in order to enable
bottom-up accounting for energy supply and demand, including:
●renewable resources,
●conventional fuels,
●energy consuming technology stocks (e.g., vehicles, appliances, dwellings, buildings), and
●all intermediate energy flows (e.g., electricity and heat).
Energy and GHG emissions values are derived from a series of connected stock and flow models,
evolving based on current and future geographic and technology decisions/assumptions (e.g., EV
uptake rates). The model accounts for physical flows (e.g., energy use, new vehicles by technology,
VMT) as determined by stocks (buildings, vehicles, heating equipment, etc.).
The model applies a system dynamics approach. For any given year, the model traces the flows
and transformations of energy from sources through energy currencies (e.g., gasoline, electricity,
hydrogen) to end uses (e.g., personal vehicle use, space heating) to energy costs and to GHG
emissions. An energy balance is achieved by accounting for efficiencies, technology conversion,
and trade and losses at each stage in the journey from source to end use.
Table 2. Model characteristics.
Characteristic Rationale
Integrated The tool models and accounts for all city-scale energy and emissions in relevant sectors
and captures relationships between sectors. The demand for energy services is modelled
independently of the fuels and technologies that provide the energy services. This
decoupling enables exploration of fuel switching scenarios. Feasible scenarios are
established when energy demand and supply are balanced.
Scenario-based Once calibrated with historical data, the model enables the creation of dozens of
scenarios to explore different possible futures. Each scenario can consist of either one or
a combination of policies, actions, and strategies. Historical calibration ensures that
scenario projections are rooted in observed data.
Spatial Built environment configuration determines walkability and cyclability, accessibility to
transit, feasibility of district energy, and other aspects. The model therefore includes
spatial dimensions that can include as many zones (the smallest areas of geographic
analysis) as deemed appropriate. The spatial components can be integrated with GIS
systems, land-use projections, and transportation modeling.
GPC-compliant The model is designed to report emissions according to the GHG Protocol for Cities (GPC)
framework and principles.
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Economic
impacts
The model incorporates a high-level financial analysis of costs related to energy
(expenditures on energy) and emissions (carbon pricing, social cost of carbon), as well as
operating and capital costs for policies, strategies, and actions. This allows for the
generation of marginal abatement costs.
Model Structure
The major components of the model and the first level of their modelled relationships (influences)
are represented by the blue arrows in Figure 3. Additional relationships may be modelled by
modifying inputs and assumptions—specified directly by users, or in an automated fashion by
code or scripts running “on top of” the base model structure. Feedback relationships are also
possible, such as increasing the adoption rate of non-emitting vehicles in order to meet a GHG
emissions constraint.
The model is spatially explicit. All buildings, transportation, and land-use data are tracked within
the model through a GIS platform, and by varying degrees of spatial resolution. A zone type
system is applied to divide the City into smaller configurations, based on the City’s existing traffic
zones (or another agreeable zone system). This enables consideration of the impact of land-use
patterns and urban form on energy use and emissions production from a base year to future
dates using GIS-based platforms. The model’s GIS outputs will be integrated with the City’s
mapping systems.
For any given year various factors shape the picture of energy and emissions flows, including: the
population and the energy services it requires; commercial floorspace; energy production and
trade; the deployed technologies which deliver energy services (service technologies); and the
deployed technologies which transform energy sources to currencies (harvesting technologies).
The model is based on an explicit mathematical relationship between these factors—some
contextual and some part of the energy consuming or producing infrastructure—and the energy
flow picture.
Some factors are modelled as stocks—counts of similar things, classified by various properties. For
example, population is modelled as a stock of people classified by age and gender. Population
change over time is projected by accounting for: the natural aging process, inflows (births,
immigration), and outflows (deaths, emigration). The fleet of personal use vehicles, an example of
a service technology, is modelled as a stock of vehicles classified by size, engine type and model
year, with a similarly classified fuel consumption intensity. As with population, projecting change in
the vehicle stock involves aging vehicles and accounting for major inflows (new vehicle sales) and
major outflows (vehicle discards). This stock-turnover approach is applied to other service
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technologies (e.g., furnaces, water heaters) and harvesting technologies (e.g., electricity generating
capacity).
Figure 3. Representation of the CiS model structure.
Sub-Models
Population and Demographics
City-wide population is modelled using the standard population cohort-survival method,
disaggregated by single year of age and gender. It accounts for typical components of change:
births, deaths, immigration and emigration. The age-structured population is important for
analysis of demographic trends, generational differences and implications for shifting energy use
patterns. These numbers are calibrated against existing projections.
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Residential Buildings
Residential buildings are spatially located and classified using a detailed set of 30+ building
archetypes capturing footprint, height and type (single, double, row, apt. high, apt. low), and year
of construction. This enables a “box” model of buildings that helps to estimate the surface area,
and model energy use and simulate the impact of energy efficiency measures based on what we
know about the characteristics of the building. Coupled with thermal envelope performance and
degree-days the model calculates space conditioning energy demand independent of any space
heating or cooling technology and fuel. Energy service demand then drives stock levels of key
service technologies including heating systems, air conditioners, water heaters. These stocks are
modelled with a stock-turnover approach capturing equipment age, retirements, and
additions—exposing opportunities for efficiency gains and fuel switching, but also showing the
rate limits to new technology adoption and the effects of lock-in (obligation to use
equipment/infrastructure/fuel type due to longevity of system implemented). Residential building
archetypes are also characterized by the number of contained dwelling units, allowing the model
to capture the energy effects of shared walls but also the urban form and transportation
implications of population density.
Non-Residential Buildings
These are spatially located and classified by a detailed use/purpose-based set of 50+ archetypes.
The floorspace of these archetypes can vary by location. Non-residential floorspace produces
waste and demand for energy and water, and provides an anchor point for locating employment
of various types.
Spatial Population and Employment
City-wide population is made spatial through allocation to dwellings, using assumptions about
persons-per-unit by dwelling type. Spatial employment is projected via two separate mechanisms:
●population-related services and employment, which is allocated to corresponding building
floorspace (e.g., teachers to school floorspace), and
●floorspace-driven employment (e.g., retail employees per square foot).
Passenger Transportation
The model includes a spatially explicit passenger transportation sub-model that responds to
changes in land-use, transit infrastructure, vehicle technology, travel behaviour change, and other
factors. Trips are divided into four types (home-work, home-school, home-other, and
non-home-based), each produced and attracted by different combinations of spatial drivers
(population, employment, classrooms, non-residential floorspace). Trips are distributed and trip
volumes are specified for each zone of origin and zone of destination pair. For each
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origin-destination pair, trips are shared over walk/bike (for trips within the walkable distance
threshold), public transit (for trips whose origin and destination are serviced by transit), and
automobile. A projection of total personal vehicles miles travelled (VMT) and a network distance
matrix are produced following the mode share calculation. The energy use and emissions
associated with personal vehicles is calculated by assigning VMT to a stock-turnover personal
vehicle model. The induced approach is used to track emissions. All internal trips (trips within the
boundary) are accounted for, as well as half of the trips that terminate or originate within the
municipal boundary. Figure 4 displays trip destination matrix conceptualization.
Figure 4. Conceptual diagram of trip categories.
Waste and Wastewater
Households and non-residential buildings generate solid waste and wastewater. The model traces
various pathways to disposal, compost, and sludge including those which capture energy from
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incineration and recovered gas. Emissions accounting is performed throughout the waste
sub-model.
Energy Flow and Local Energy Production
Energy produced from primary sources (e.g., solar, wind) is modelled alongside energy converted
from imported fuels (e.g., electricity generation, district energy, CHP). As with the transportation
sub-model, the district energy supply model has an explicit spatial dimension and can represent
areas served by district energy networks.
Finance and Employment
Energy related financial flows and employment impacts are captured through an additional layer
of model logic (not shown explicitly in Figure 2). Calculated financial flows include the capital,
operating, and maintenance cost of energy consuming stocks and energy producing stocks,
including fuel costs. Employment related to the construction of new buildings, retrofit activities
and energy infrastructure is modelled. The financial impact on businesses and households of
implementing the strategies is assessed. Local economic multipliers are also applied to
investments.
Consumption Emissions
Emissions attributable to the production of some items produced outside, but consumed in, Ames
are estimated and included in the emissions inventory and modeling (e.g., those for electronics,
food, and clothing). These are estimated based on the number of households and a weighted
average consumption per household across all income levels. A total base year emissions value is
derived by multiplying the weighted average emissions per household intensity by number of
households. This methodology enables accurate comparison to previous Ames inventories.
Model Calibration for Local Context
Data Request and Collection
Local data was supplied by the municipality. Assumptions were identified to supplement any gaps
in observed data. The data and assumptions were applied in modeling per the process described
below.
Zone System
The model is spatially explicit: population, employment, residential, and non-residential floorspace
are allocated and tracked spatially within the City’s zone system (see Figure 5). These elements
drive stationary energy demand. The passenger transportation sub-model, which drives
transportation energy demand, also operates within the same zone system.
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Figure 5. Zone system used in modelling.
Buildings
Buildings data, including building type, building footprint area, number of stories, total floorspace
area, number of units, and year built was sourced from City property assessment data. Buildings
were allocated to specific zones using their spatial attributes, based on the zone system. Buildings
are classified using a detailed set of building archetypes (see Appendix 2). These archetypes
capture footprint, height and type (e.g., single-family home, semi-attached home, etc.), enabling
the creation of a “box” model of buildings, and an estimation of surface area for all buildings.
Residential Buildings
The model multiplies the residential building surface area by an estimated thermal conductance
(heat flow per unit surface area per degree day) and the number of degree days (heating and
cooling) to derive the energy transferred out of the building during winter months and into the
building during summer months. The energy transferred through the building envelope, the solar
gain through the building windows, and the heat gains from equipment inside the building
constitute the space conditioning load to be provided by the heat systems and the air
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conditioning. The initial thermal conductance estimate is a regional average by dwelling type from
a North American energy system simulator, calibrated for the Midwest. This initial estimate is
adjusted through the calibration process as the modelled energy consumption from the market
profile in the 2015 Residential Energy Consumption Survey (RECS) and City property assessment
data.
Non-Residential Buildings
The model calculates the space conditioning load as it does for residential buildings with two
distinctions: the thermal conductance parameter for non-residential buildings is based on floor
space area instead of surface area, and incorporates data from Ames.
Starting values for output energy intensities and equipment efficiencies for non-residential end
uses are taken from the 2012 Commercial Buildings Energy Consumption Survey (CBECS). All
parameter estimates are further adjusted during the calibration process. The calibration target for
non-residential building energy use is the observed commercial and industrial fuel consumption in
the base year.
Using assumptions for thermal envelope performance for each building type, the model calculates
total energy demand for all buildings, independent of any space heating or cooling technology and
fuel.
Population and Employment
Federal census population and employment data was spatially allocated to residential (population)
and non-residential (employment) buildings. This enables indicators to be derived from the model,
such as emissions per household, and drives the BAU energy and emissions projections for
buildings, transportation, waste.
Population for 2018 was spatially allocated to residential buildings using initial assumptions about
persons-per-unit (PPU) by dwelling type. These initial PPUs are then adjusted so that the total
population in the model (which is driven by the number of residential units by type multiplied by
PPU by type) matches the total population from census/regional data.
Employment for 2018 was spatially allocated to non-residential buildings using initial assumptions
for two main categories: population-related services and employment, allocated to corresponding
building floorspace (e.g., teachers to school floorspace); and floorspace-driven employment (e.g.,
retail employees per square foot). Like population, these initial ratios are adjusted within the
model so that the total employment derived by the model matches total employment from
census/regional data.
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Transportation
The model includes a spatially explicit passenger transportation sub-model that responds to
changes in land-use, transit infrastructure, vehicle technology, travel behaviour change, and other
factors. Trips are divided into four types (home-work, home-school, home-other, and
non-home-based), each produced and attracted by a different combination of spatial drivers
(population, employment, classrooms, non-residential floorspace). Trip volumes are distributed as
pairs for each zone of origin and zone of destination. For each origin-destination pair, trips are
shared over walk/bike (for trips within the walkable distance threshold), public transit (for trips
whose origin and destination are serviced by transit), and automobile. Total personal vehicle miles
travelled (VMT) is produced when modeling mode shares and distances. The energy use and
emissions associated with personal vehicles is calculated by assigning VMT to model personal
vehicle ownership.
The passenger transportation model is anchored with origin-destination trip matrices by trip
mode and purpose, generated by the City’s transportation department. The results are
cross-checked against indicators such as average annual VMT per vehicle. For medium-heavy duty
commercial vehicle transportation, the ratio of local retail diesel fuel sales to State retail diesel fuel
sales was applied to estimate non-retail diesel use.
The modelled stock of personal vehicles by size, fuel type, efficiency, and vintage was informed by
regional vehicle registration statistics. The total number of personal-use and corporate vehicles is
proportional to the projected number of households in the BAU.
The GPC induced activity approach is used to account for emissions. Using this approach, all
internal trips (within boundary) as well as half of the trips that terminate or originate within the
municipal boundary are accounted for. This approach allows the municipality to understand its
transportation impacts on its peripheries and the region.
Transit VMT and fuel consumption was modelled based on data provided by Ames in the 2018
emissions inventory data.
Waste
Solid waste stream composition and routing data (landfill, composting, recycling) was sourced
from local data sources. The base carbon content in the landfill was estimated based on historical
waste production data. Total methane emissions were estimated for landfills using the first order
decay model, with the methane generation constant and methane correction factor set to default,
as recommended by, and based on values from, IPCC Guidelines for landfill emissions. Data on
methane removed via recovery was provided by the landfills.
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Data and Assumptions
Scenario Development
The model supports the use of scenarios as a mechanism to evaluate potential futures for
communities. A scenario is an internally consistent view of what the future might turn out to
be—not a forecast, but one possible future outcome. Scenarios must represent serious
considerations defined by planning staff and community members. They are generated by
identifying population projections into the future, identifying how many additional households are
required, and then applying those additional households according to existing land-use plans
and/or alternative scenarios. A simplified transportation model evaluates the impact of the new
development on transportation behaviour, building types, agricultural and forest land, and other
variables.
Business-As-Usual Scenario
The Business-As-Usual (BAU) scenario estimates energy use and emissions volumes from the base
year (2018) to the target year (2050). It assumes an absence of substantially different policy
measures from those currently in place.
Methodology
1.Calibrate model and develop 2018 base year using observed data and filling in gaps with
assumptions where necessary.
2.Input existing projected quantitative data to 2050 where available:
-Population, employment and housing projections by transport zone
-Build out (buildings) projections by transport zone
-Transportation modeling from the municipality
3.Where quantitative projections are not carried through to 2050, extrapolate the projected
trend to 2050.
4.Where specific quantitative projections are not available, develop projections through:
-Analyzing current on the ground action (reviewing action plans, engagement with
staff, etc.), and where possible, quantifying the action.
-Analyzing existing policy that has potential impact and, where possible, quantifying
the potential impact.
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Low-Carbon Scenario
The model projects how energy flow and emissions profiles will change in the long-term by
modeling potential changes in the context (e.g., population, development patterns), projecting
energy services demand intensities, waste production and diversion rates, industrial processes,
and projecting the composition of energy system infrastructure.
Policies, Actions, and Strategies
Alternative behaviours of various energy system actors (e.g., households, various levels of
government, industry, etc.) can be mimicked in the model by changing the values of the model’s
user input variables. Varying their values creates "what if" type scenarios, enabling a flexible
mix-and-match approach to behavioral models which connect to the physical model. The model
can explore a wide variety of policies, actions and strategies via these variables. The resolution of
the model enables the user to apply scenarios to specific neighbourhoods, technologies, building
or vehicle types or eras, and configurations of the built environment.
Methodology
1.Develop a list of potential actions and strategies;
2.Identify the technological potential of each action or group of actions to reduce energy and
emissions by quantifying the actions:
a.If the action or strategy specifically incorporates a projection or target; or,
b.If there is a stated intention or goal, review best practices and literature to quantify
that goal; and
c.Identify any actions that are overlapping and/or include dependencies on other
actions.
3.Translate the actions into quantified assumptions over time;
4.Apply the assumptions to relevant sectors in the model to develop a low-carbon scenario
(i.e., apply the technological potential of the actions to the model);
5.Analyze results of the low-carbon scenario against the overall target;
6.If the target is not achieved, identify variables to scale up and provide a rationale for doing
so;
7.Iteratively adjust variables to identify a pathway to the target; and
8.Develop a marginal abatement cost curve for the low-carbon scenario.
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Addressing Uncertainty
There is extensive discussion of the uncertainty in models and modeling results. The assumptions
underlying a model can be from other locations or large data sets and do not reflect local
conditions or behaviours, and even if they did accurately reflect local conditions, it is exceptionally
difficult to predict how those conditions and behaviours will respond to broader societal changes
and what those broader societal changes will be.
The WhatIf?/SSG modeling approach uses four strategies for managing uncertainty applicable to
community energy and emissions modeling:
1.Sensitivity analysis:One of the most basic ways of studying complex models is sensitivity
analysis, which helps quantify uncertainty in a model’s output. To perform this assessment,
each of the model’s input parameters is drawn from a statistical distribution in order to
capture the uncertainty in the parameter’s true value (Keirstead, Jennings, & Sivakumar,
2012).
Approach:Selected variables are modified by ±10-20%to illustrate the impact that an error of
that magnitude has on the overall total.
2.Calibration:One way to challenge untested assumptions is the use of ‘back-casting’ to
ensure the model can ‘forecast the past’ accurately. The model can then be calibrated to
generate historical outcomes, calibrating the model to better replicate observed data.
Approach:Variables are calibrated in the model using two independent sources of data. For
example, the model calibrates building energy use (derived from buildings data) against actual
electricity data from the electricity distributor.
3.Scenario analysis:Scenarios are used to demonstrate that a range of future outcomes are
possible given the current conditions and that no one scenario is more likely than another.
Approach:The model will develop a reference scenario.
4.Transparency:The provision of detailed sources for all assumptions is critical to enabling
policy-makers to understand the uncertainty intrinsic in a model.
Approach:Modeling assumptions and inputs are presented in this document.
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Appendix 1: GPC Emissions Scope Table for Detailed Model
Green rows = Sources required for GPC BASIC inventory
Blue rows = Sources required GPC BASIC+ inventory
Red rows = Sources required for territorial total but not for BASIC/BASIC+ reporting
Exclusion Rationale Legend
N/A Not Applicable, or not included in scope
ID Insufficient Data
NR No Relevance, or limited activities identified
Other Reason provided in other comments
GPC ref
No.Scope GHG Emissions Source Inclusion Exclusion
rationale
I STATIONARY ENERGY SOURCES
I.1 Residential buildings
I.1.1 1 Emissions from fuel combustion within the city boundary Yes
I.1.2 2 Emissions from grid-supplied energy consumed within the city boundary Yes
I.1.3 3 Emissions from transmission and distribution losses from grid-supplied
energy consumption
Yes
I.2 Commercial and institutional buildings/facilities
I.2.1 1 Emissions from fuel combustion within the city boundary Yes
I.2.2 2 Emissions from grid-supplied energy consumed within the city boundary Yes
I.2.3 3 Emissions from transmission and distribution losses from grid-supplied
energy consumption
Yes
I.3 Manufacturing industry and construction
I.3.1 1 Emissions from fuel combustion within the city boundary Yes
I.3.2 2 Emissions from grid-supplied energy consumed within the city boundary Yes
I.3.3 3 Emissions from transmission and distribution losses from grid-supplied
energy consumption
Yes
I.4 Energy industries
I.4.1 1 Emissions from energy used in power plant auxiliary operations within the
city boundary
Yes
I.4.2 2 Emissions from grid-supplied energy consumed in power plant auxiliary
operations within the city boundary
Yes
I.4.3 3 Emissions from transmission and distribution losses from grid-supplied
energy consumption in power plant auxiliary operations
Yes
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I.4.4 1 Emissions from energy generation supplied to the grid No NR
I.5 Agriculture, forestry and fishing activities
I.5.1 1 Emissions from fuel combustion within the city boundary Yes
I.5.2 2 Emissions from grid-supplied energy consumed within the city boundary Yes
I.5.3 3 Emissions from transmission and distribution losses from grid-supplied
energy consumption
Yes
I.6 Non-specified sources
I.6.1 1 Emissions from fuel combustion within the city boundary No NR
I.6.2 2 Emissions from grid-supplied energy consumed within the city boundary No NR
I.6.3 3 Emissions from transmission and distribution losses from grid-supplied
energy consumption
No NR
I.7 Fugitive emissions from mining, processing, storage, and transportation of coal
I.7.1 1 Emissions from fugitive emissions within the city boundary No NR
I.8 Fugitive emissions from oil and natural gas systems
I.8.1 1 Emissions from fugitive emissions within the city boundary Yes
II TRANSPORTATION
II.1 On-road transportation
II.1.1 1 Emissions from fuel combustion for on-road transportation occurring within
the city boundary
Yes
II.1.2 2 Emissions from grid-supplied energy consumed within the city boundary for
on-road transportation
Yes
II.1.3 3 Emissions from portion of transboundary journeys occurring outside the city
boundary, and transmission and distribution losses from grid-supplied
energy consumption
Yes
II.2 Railways
II.2.1 1 Emissions from fuel combustion for railway transportation occurring within
the city boundary
No N/A
II.2.2 2 Emissions from grid-supplied energy consumed within the city boundary for
railways
No N/A
II.2.3 3 Emissions from portion of transboundary journeys occurring outside the city
boundary, and transmission and distribution losses from grid-supplied
energy consumption
No N/A
II.3 Water-borne navigation
II.3.1 1 Emissions from fuel combustion for waterborne navigation occurring within
the city boundary
No NR
II.3.2 2 Emissions from grid-supplied energy consumed within the city boundary for
waterborne navigation
No NR
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II.3.3 3 Emissions from portion of transboundary journeys occurring outside the city
boundary, and transmission and distribution losses from grid-supplied
energy consumption
No NR
II.4 Aviation
II.4.1 1 Emissions from fuel combustion for aviation occurring within the city
boundary
Yes
II.4.2 2 Emissions from grid-supplied energy consumed within the city boundary for
aviation
Yes
II.4.3 3 Emissions from portion of transboundary journeys occurring outside the city
boundary, and transmission and distribution losses from grid-supplied
energy consumption
No ID
II.5 Off-road
II.5.1 1 Emissions from fuel combustion for off-road transportation occurring within
the city boundary
Yes
II.5.2 2 Emissions from grid-supplied energy consumed within the city boundary for
off-road transportation
No ID
III WASTE
III.1 Solid waste disposal
III.1.1 1 Emissions from solid waste generated within the city boundary and disposed
in landfills or open dumps within the city boundary
No NR
III.1.2 3 Emissions from solid waste generated within the city boundary but disposed
in landfills or open dumps outside the city boundary
Yes
III.1.3 1 Emissions from waste generated outside the city boundary and disposed in
landfills or open dumps within the city boundary
No N/A
III.2 Biological treatment of waste
III.2.1 1 Emissions from solid waste generated within the city boundary that is
treated biologically within the city boundary
Yes
III.2.2 3 Emissions from solid waste generated within the city boundary but treated
biologically outside of the city boundary
No ID
III.2.3 1 Emissions from waste generated outside the city boundary but treated
biologically within the city boundary
No N/A
III.3 Incineration and open burning
III.3.1 1 Emissions from solid waste generated and treated within the city boundary Yes
III.3.2 3 Emissions from solid waste generated within the city boundary but treated
outside of the city boundary
No N/A
III.3.3 1 Emissions from waste generated outside the city boundary but treated
within the city boundary
No N/A
III.4 Wastewater treatment and discharge
III.4.1 1 Emissions from wastewater generated and treated within the city boundary Yes
23
III.4.2 3 Emissions from wastewater generated within the city boundary but treated
outside of the city boundary
No NR
III.4.3 1 Emissions from wastewater generated outside the city boundary No N/A
IV INDUSTRIAL PROCESSES AND PRODUCT USE (IPPU)
IV.1 1 Emissions from industrial processes occurring within the city boundary No ID
IV.2 1 Emissions from product use occurring within the city boundary No ID
V AGRICULTURE, FORESTRY AND LAND USE (AFOLU)
V.1 1 Emissions from livestock within the city boundary Yes
V.2 1 Emissions from land within the city boundary No NR
V.3 1 Emissions from aggregate sources and non-CO2 emission sources on land
within the city boundary
No ID
VI OTHER SCOPE 3
VI.1 3 Other Scope 3 Yes
TOTAL
24
Appendix 2: Building Types in the model
Residential Building Types Non-residential Building Types
Single_detached_1Storey_tiny
Single_detached_2Storey_tiny
Single_detached_3Storey_tiny
Single_detached_1Storey_small
Single_detached_2Storey_small
Single_detached_3Storey_small
Single_detached_1Storey_medium
Single_detached_2Storey_medium
Single_detached_3Storey_medium
Single_detached_1Storey_large
Single_detached_2Storey_large
Single_detached_3Storey_large
Double_detached_1Storey_small
Double_detached_2Storey_small
Double_detached_3Storey_small
Double_detached_1Storey_large
Double_detached_2Storey_large
Double_detached_3Storey_large
Row_house_1Storey_small
Row_house_2Storey_small
Row_house_3Storey_small
Row_house_1Storey_large
Row_house_2Storey_large
Row_house_3Storey_large
Apartment_1To4Storey_small
Apartment_1To4Storey_large
Apartment_5To14Storey_small
Apartment_5To14Storey_large
Apartment_15To24Storey_small
Apartment_15To24Storey_large
Apartment_25AndUpStorey_small
Apartment_25AndUpStorey_large
inMultiUseBldg
college_university
school
retirement_or_nursing_home
special_care_home
hospital
municipal_building
fire_station
penal_institution
police_station
military_base_or_camp
transit_terminal_or_station
airport
parking
hotel_motel_inn
greenhouse
greenspace
recreation
community_centre
golf_course
museums_art_gallery
retail
vehicle_and_heavy_equiptment_service
warehouse_retail
restaurant
commercial_retail
commercial
commercial_residential
retail_residential
warehouse_commercial
warehouse
religious_institution
surface_infrastructure
energy_utility
water_pumping_or_treatment_station
industrial_generic
food_processing_plants
textile_manufacturing_plants
furniture_manufacturing_plants
refineries_all_types
chemical_manufacturing_plants
printing_and_publishing_plants
fabricated_metal_product_plants
manufacturing_plants_miscellaneous
_processing_plants
asphalt_manufacturing_plants
concrete_manufacturing_plants
industrial_farm
barn
25
Appendix 3: Emissions Factors Used
Category Value Comment
Natural gas CO2: 53.02 kg/MMBtu
CH4: 0.005 kg/MMBtu
N2O: 0.0001kg/MMBtu
ICLEI–Local Governments for Sustainability USA. "US
community protocol for accounting and reporting of
greenhouse gas emissions." (2012).
Electricity 2018
CO2e: 1,098 lbs CO2e per MWh
MROW average emissions factor per US EPA eGRID
(www.epa.gov/egrid/data-explorer)
Gasoline CO2: 0.07024 MT/MMBtu
CH4: 0.000000017343 MT/mile
N2O: 0.000000009825 MT/mile
ICLEI–Local Governments for Sustainability USA. "US
community protocol for accounting and reporting of
greenhouse gas emissions." (2012).
Diesel CO2: 0.073934483 MT/MMBtu
CH4: 0.000000001 MT/vehicle mile
N2O: 0.0000000015 MT/vehicle mile
ICLEI–Local Governments for Sustainability USA. "US
community protocol for accounting and reporting of
greenhouse gas emissions." (2012).
Fuel oil CO2: 73.9 kg per mmBtu
CH4: 0.003 kg per mmBtu
N2O: 0.0006 kg per mmBtu
Environmental Protection Agency. "Emission factors for
greenhouse gas inventories."Stationary Combustion Emission
Factors," US Environmental Protection Agency2014, Available:
https://www.epa.gov/sites/production/files/2015-07/documents/e
mission-factors_2014.pdf (2014).
Table 1 Stationary Combustion Emission Factor, Fuel Oil No. 2
Wood CO2: 93.80 kg per mmBtu
CH4: 0.0072 kg per mmBtu
N2O: 0.0036 kg per mmBtu
Environmental Protection Agency. "Emission factors for
greenhouse gas inventories."Stationary Combustion Emission
Factors," US Environmental Protection Agency2014, Available:
https://www.epa.gov/sites/production/files/2015-07/documents/e
mission-factors_2014.pdf (2014).
Table 1 Stationary Combustion Emission Factor, Biomass fuels:
Wood and Wood Residuals
Propane CO2: 62.87 kg per mmBtu
CH4 : 0.003 kg per mmBtu
N2O: 0.0006 kg per mmBtu
For mobile combustion:
CO2: 5.7 kg per gallon
Environmental Protection Agency. "Emission factors for
greenhouse gas inventories."Stationary Combustion Emission
Factors," US Environmental Protection Agency2014, Available:
https://www.epa.gov/sites/production/files/2015-07/documents/e
mission-factors_2014.pdf (2014).
Table 1 Stationary Combustion Emission Factor, Petroleum
Products: Propane
Table 2 Mobile Combustion CO2 Emission Factors: Propane
Waste Landfill emissions are calculated from
first order decay of degradable
organic carbon deposited in landfill.
Derived emission factor in 2018 to be
determined based on % recovery of
Landfill emissions: IPCC Guidelines Vol 5. Ch 3, Equation 3.1
26
landfill methane and waste
composition.
Wastewater CH4: 0.48 kg CH4/kg BOD
N2O: 3.2 g / (person * year) from
advanced treatment
0.005 g /g N from wastewater
discharge
CH4 wastewater: IPCC Guidelines Vol 5. Ch 6, Tables 6.2 and
6.3; MCF value for anaerobic digester
N2O from advanced treatment: IPCC Guidelines Vol 5. Ch 6,
Box 6.1
N2O from wastewater discharge: IPCC Guidelines Vol 5. Ch 6,
Section 6.3.1.2
Greenhouse
gases
Carbon dioxide (CO2), methane
(CH4) and nitrous oxide (N20) are
included.
Global Warming Potential
CO2 = 1
CH4 = 34
N2O = 298
Hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur
hexafluoride (SF6), and nitrogen trifluoride (NF3) are not
included.
27
City of Ames Climate Action Plan (CAP) and Target-Setting
Briefing note: GHG reduction targets for consideration
November 2021
Issue
The City Steering Committee needs to establish a target for the Climate Action Plan to be
developed. The first step in establishing this target is for the Steering Committee (SC) to
understand the different target options and their implications in order to establish a target
that best meets the needs of the Ames community.
Context
The City of Ames is responding to the climate emergency by setting a greenhouse gas
(GHG) emissions reduction target and developing a Climate Action Plan (CAP). The CAP will
provide a framework including a recommended pathway and set of doable actions for
reaching Ames’ greenhouse gas reduction target, once it has been set.
The process is both technical and community-based. The CAP planning process provides
the opportunity for the community to rethink how homes and businesses are built and
heated, how to move around the city, and how to reduce and manage waste. Input from
stakeholders, including the public, is being sought as technical analysis is being conducted
to understand Ames’ current situation and opportunities to forge a new pathway.
At this point in the project, SSG, the consultant assisting the City in developing the CAP, has
developed a business-as-usual (BAU) scenario. The BAU outlines a plausible scenario of
energy use and greenhouse gas emissions in the community out to 2050 if new climate
actions are not pursued. In this scenario, emissions in Ames are similar in 2018 and 2050.
With the BAU established, SSG has been tasked with proposing GHG emissions reduction
targets for the City Steering Committee to consider. The targets proposed in this briefing
draw on insights from best practices nationally and globally, the science-based guidance
from the Global Covenant of Mayors, and targets from other similar-sized cities in the
mid-west, from state governments, and from the federal government. Potential benefits
and challenges relating to each target are in line with case studies and SSG’s direct
experience in other communities and. They also consider the results of the BAU scenario.
The targets are being shared with the SC at this time for consideration, and to
provide an opportunity for questions. Following the project plan, the SC is scheduled
to decide on a target after consultation with the Supplemental Input Committee and
the public has occurred and the results from the engagements have been presented.
Background
Greenhouse gas emissions targets at the local government level are an important planning
tool for decreasing emissions. A target also demonstrates a commitment to climate action.
Since 2018, net-zero by 2050 has been the benchmark target for all jurisdictions around the
world, including national, state, and local governments, with significant discussion around
the importance of interim targets and pathways to the 2050 target. Net-zero by 2050 aligns
with the goals of the United Nations Framework Convention on Climate Change (UNFCCC)
Paris Agreement and the Intergovernmental Panel on Climate Change (IPCC) Special Report
on Global Warming of 1.5°C. Achieving this target decreases the likelihood of catastrophic
global climate change impacts. As of June 2021, 137 national governments around the
world, including the United States, have pledged to reach net-zero emissions by 2050 or
sooner . Many state and local governments have also set net-zero by 2050 targets, some1
with more aggressive interim targets than their national governments, recognizing that
interim targets and the pathway to net-zero are as or more important than the 2050
net-zero target itself.
Discussion
This briefing explains net-zero by 2050 as a standard goal, and its alignment with the U.S.
federal target, the UNFCCC Paris Agreement, and IPCC recommendations. It also details
four pathways to reach net-zero.
The pathways to an emissions target can vary greatly (Figure 1) and the appropriate
pathway for Ames is the subject of consideration for the SC. Different pathways result in
much more (right figure) or much fewer (left figure) emissions being released overall
between now and 2050. The amount of emissions released over the next thirty years is just
as significant for staying within the 1.5°C to 2.0°C warming threshold (recommended by the
IPCC and UNFCCC Paris Agreement)as reaching net-zero by 2050. Delaying action results in
more emissions released over the period before the target year. It also requires a transition
so rapid as the target year approaches that actions may contribute to or create undesirable
social and financial impacts. At the same time, it is important for each local government to
carefully consider the rate at which it can transition to a low carbon economy given the
constraints in which it operates.
1 Energy & Climate Intelligence Unit | Net Zero Tracker (eciu.net)
Figure 1. Emissions reductions pathways are associated with the timing of actions and setting interim
targets.
This briefing proposes four potential pathways to net-zero for the Ames community. The
pathways explored include:
●A science-based target (general)
●A science-based target using a carbon budge and fair share approach
●A target aligning with the United Sates’ federal target
●An evidence-based target
This briefing discusses the associated 2050 and 2030 emissions reductions for each target,
the source of the target, the background behind the target being described, and a brief
analysis of the target from SSG’s perspective with supporting evidence from other sources.
This briefing also compares the targets, and their respective benefits and challenges.
Science-Based Target (General)
Target:45% minimum reduction in greenhouse emissions from 2005 levels by 2030, and
net-zero emissions by 2050.
Target Source:The Intergovernmental Panel on Climate Change (IPCC), in their 2018
report Global Warming of 1.5°C, “an IPCC Special Report on the impacts of global warming of
1.5°C above pre-industrial levels and related global GHG emission pathways, in the context
of strengthening the global response to the threat of climate change, sustainable
development, and efforts to eradicate poverty .”2
Background:In 2018, the IPCC released a report with analysis showing that in order for
the world to meet the targets set out in the UNFCCC Paris Agreement, every jurisdiction in
the world would need to decrease greenhouse gas emissions by 45% over 2005 levels by
2030, and be at net-zero emissions at or before 2050. This is based on earlier IPCC work
that states that the world must stay within 1.5°C to 2°C of warming above pre-industrial
levels to avoid the most catastrophic global impacts of climate change. The earlier work of
the IPCC is referenced in the Paris Agreement, which calls for signatory nations to create
plans that will reach net-zero emissions by 2050 and limit global warming to 1.5°C to 2°C by
calculating a nationally determined contribution (NDC) to identify the country’s interim
(2030) emissions reduction target.
Analysis:This target is ambitious and the minimum the IPCC calls for in order to, with
moderate confidence, keep global warming within the threshold of 1.5°C above
pre-industrial levels. As more recent research points out, however, this method does not
account for global equity concerns including the responsibility of wealthier nations and
their local governments to act faster to decrease emissions, allowing developing nations
more time to develop and build the capacity to decarbonize. More recent reports also raise
concerns that emissions need to begin to trend downward now to reach the 1.5°C rather
than putting off action to reach the interim and end goals just in time.
It must be made clear though that even a 45% reduction, between now and 2030 will
require transformational and systems-level change in the way that local government,
businesses, community members, institutions, other levels of government, and energy
suppliers make decisions and behave.
2 IPCC, 2018: Summary for Policymakers. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels
and related global GHG emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts
to eradicate poverty. [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia,
Science-Based Target: Carbon Budget & Fair Share Approach
Target:83% reduction in greenhouse emissions from 2018 levels by 2030, and net-zero
emissions by 2050.
Target Source:The C40 Cities Climate Leadership Group,made up of 97 cities around the
world that represents one-twelfth of the world's population and one-quarter of the global
economy and focused on addressing climate change through urban action .3
Background:The C40 Cities Climate Leadership Group has developed the methodology
used for setting the carbon budget. Along with general emissions per capita information,
the methodology takes into consideration factors such as how much GHG emissions should
be allocated to countries with high levels of poverty versus wealthy countries. This is
referred to as a ‘fair-share approach’. In order to achieve a fair-share science-based target,
cities are encouraged to create a carbon budget outlining the fair share of carbon
emissions they can emit before they hit net-zero emissions and the amount they can emit
each year before hitting their target. Cities can then plan for the actions that will help them
achieve their carbon budget.
According to the Science-Based Targets Network, “Equity is a consideration in all
recommended methodologies when calculating a city’s carbon budget. Carbon budgets are
a simplified measurement of the additional emissions that a city or country can still emit if
the world is to limit global heating to 1.5 °C. The carbon budget of a city or country will vary
based on the following factors:
1.Responsibility:GHG emissions, particularly CO2 emissions,accumulate in the
atmosphere over time. Many industrialized countries have been the source of
dangerous carbon emissions for the past 200 years. These past emissions are termed
historical emissions. Other countries are still developing their economies and are
permitted to peak their emissions later. These are called late emissions. Carbon
budgets take into account historical emissions and late emissions, tasking those
countries and cities who are most responsible for global CO2 accumulation with
reducing their emissions.
2.Capacity:it is acknowledged that different cities and countries have varied capacities to
respond to the challenge of climate change based on their respective levels of
socio-economic development.
3.Inter-generational justice: present generations have certain duties towards future
generations, in terms of decreasing climate change risks, increasing the availability of
natural resources and the health of the planet’s ecosystems.”4
4 Science Based Targets Network. November 2020. Science-Based Climate Targets: A Guide for Cities, 15p.
3 C40
Analysis:Science-based targets using a carbon budget and equity approach are
considered the current best practice for target setting and are now recommended by the
world’s leading climate organizations, including C40, CDP, Global Covenant of Mayors, ICLEI,
World Wildlife Fund, and the World Resources Institute. These targets are also among the
most aggressive emissions reductions targets. If every jurisdiction across the world were to
adopt this target and implement it, the world has the best chance of staying within the 1.5
°C threshold while, arguably, realizing equity and co-benefits to climate action.
Implementation requires swift action including capital investments, coordination at
multiple levels of government and with other stakeholders, and social and behavioral
changes at multiple scales, making this target very challenging to achieve.
Alignment with Federal Target
Target:50-52% reduction in greenhouse emissions from 2005 levels by 2030, and net-zero
emissions by 2050.
Target Source:This target is in line with the United States’ federal emissions reduction
target announced in April 2021. The target is based on the United States’ Nationally
Determined Contribution in line with Article 4 of the Paris Agreement.
Background:Nationally Determined Contributions (NDCs)are non-binding national plans
that communicate a nation’s intended climate target and the climate policies and actions
the government intends to implement to reach their stated target. An NDC is established
independently by the contributing country and must be based on:
●Climate neutrality by 2050
●Limiting global warming to well below 2 °C and pursuing efforts to limit it to
1.5 °C
●Reducing emissions of greenhouse gases (GHGs) from an established baseline
●Increasing adaptation to the harmful effects of climate change
●Adjusting financial flows to align with reducing GHG emissions
The United States only recently rejoined the Paris Agreement and developed a new NDC.
Policies and actions the current administration has outlined to reach their target include:
●100% carbon-free electricity by 2035
●Supporting energy efficiency upgrades and electrification in buildings
o A job-creating retrofit program
o Sustainable affordable housing
o Wider use of heat pumps and induction stoves
o Adoption of modern building codes for buildings
●Reducing carbon pollution from the transportation sector
o 50% of personal and light-duty vehicles sales are electric by 2035
●Industry decarbonization
o Research, development, demonstration, commercialization, and deployment
of very low-carbon and zero-carbon industrial processes and products.
o Incentivizing carbon capture
o Incentivizing new sources of hydrogen produced from renewable energy,
nuclear energy, or waste
●Agriculture decarbonization and land management
o Supporting scaling of climate-smart agricultural practices including
reforestation, rotational grazing, and nutrient management practices
o Investing in forest protection and forest management
o Supporting nature-based solutions and sequestration in waterways through
blue carbon
Analysis:Aligning with the federal target requires a 5%-7% greater decrease in emissions
by 2030 compared to a general science-based target and signifies an increase in effort at
the local level. However, if the measures identified at the federal level are implemented this
should ease the burden on local government to act, regardless of the interim target chosen
at the local level. In fact, policies identified at the federal level to achieve the United States’
NDC, including 100% carbon-free electricity by 2030 could significantly decrease the burden
on all local governments. As we have seen in the past, however, not all targets are achieved
at the national level and changes in administration can disrupt climate action, so it is critical
that local governments continue to pursue action at the local level and collaborate with
higher orders of government and other local governments.
According to an analysis of the new federal target, full implementation would see emissions
in the United States drop to a level that limits global warming to 2 °C (if all countries were
to adopt a similar goal) but would not reach the ideal 1.5 °C limit. The U.S. target does not
take into account a fair share target .5
5 USA | Climate Action Tracker
Evidence-Based Target
Target:Greenhouse emissions reductions by 2030 to be determined through modeling
using a bottom-up approach, and net-zero emissions by 2050.
Target Source:This target is a hybrid of a science-based target approach and a bottom-up
approach to identifying a target.
Background:Evidence-based targets are sometimes used when a community recognizes
the need to implement a science-based approach based on best practices (option two in
this briefing) but has legitimate concerns about its ability to reach the target due to the
local conditions and constraints the community faces. Local conditions and constraints that
cause significant concern around reaching an interim target may include the financial and
economic situation of the City, significant industry presence in the community which the
City and its residents have little agency to influence, and/or a lack of commitment from
higher orders of government that control energy assets used by the community. During the
modeling process, the consulting team may find additional constraints relating to the
feasibility of decarbonization in all sectors. In this situation, a community may choose to
recognize the need for a science-based target while stating what is within their agency to
achieve, and committing to working towards changing conditions to realize a science-based
target or get closer to it.
Analysis:This approach likely does not meet the threshold for a science-based target as
defined by the IPCC, the Science-Based Reporting Network, or emissions reporting bodies,
including the Global Covenant of Mayors. It is a pragmatic and conservative approach
rooted in the realities of local constraints, and can still include aggressive and
transformative action at the local level. Setting this target should still recognize the need to
work towards changing conditions and best practices. A community establishing an
evidence-based target should be prepared to exercise adaptive management and reassess
the target over time as conditions change. In other words, a community choosing this type
of target should still put actions in motion and identify a pathway to get as much done as
quickly as possible but set the race to the carbon budget and science-based target aside
while it works on addressing systemic constraints, rather than simply waiting for changes
by others.
Comparing Target Approaches
Other than continuing with the business-as-usual scenario, all targets outlined result in
net-zero emissions by 2050. As presented in the table below, the pathways to get there can
differ greatly. A general science-based target and aligning with the federal target have
similar trajectories, with emissions in the 600-700 ktCo2e range by 2030. Note that the
2030 reductions for the general science-based target and aligning with the federal target
are currently based on reductions from 2018, and SSG would conduct a comprehensive
analysis of the 2030 target based on the 2005 baseline if one of these targets is selected.
The current projections should be treated as estimates. The science-based target using a
carbon budget and fair share approach reduces emissions much sooner, to around 215
ktCO2e by 2030. An evidence-based trajectory is not included in the chart because a
trajectory is not clear until the scenario is built from the bottom-up.
Each of the targets and pathways is also subject to some benefits and challenges. The table
below summarizes some of these but the lists are not exhaustive.
Benefits Challenges
Science-based
target
●Aligned with the UNFCCC Paris Agreement
●Aligned with the 2018 IPCC
recommendations
●Similar target to many other jurisdictions
(local and national) which may create
synergies, peer exchange, and reduce
legislative issues and resistance
●Avoids some costly infrastructure lock-in
●Has potential to realize co-benefits at a
local level- clean air, connected community
●Does not address global equity concerns
●Does not align with the most recent evidence
for requirements for staying within the 1.5°C
threshold
●Challenging systems-level changes required
●Extensive behavior change required
●Ongoing political will required
●Some costly infrastructure lock-in will occur
●Significant up-front capital costs
Science-based
target using a
carbon budget
and fair-share
approach
●Aligned with the UNFCCC Paris Agreement
●Aligned with the 2018 IPCC
recommendations for limiting warming to
1.5 °C
●Aligns with the Science-Based Target
Network’s recommendations for cities
●Avoids costly infrastructure lock-in
●Maximizes co-benefits - equity, cleaner air,
more connected communities
●Has potential to realize co-benefits at a
local level sooner
●Significant up-front capital costs
●Challenging systems-level changes required
●Extensive behavior change required
●Ongoing political will required
●Potential for resistance due to quick,
transformative changes
Aligning with
the United
Sates’ federal
target
●Aligned with the UNFCCC Paris Agreement
●Aligned with the 2018 IPCC
recommendations
●Similar target to many other jurisdictions
(local and national) which may create
synergies, peer exchange, and reduce
●Does not address global equity concerns
●Does not align with the most recent evidence
for requirements for staying within the 1.5°C
threshold
●Challenging systems-level changes required
●Extensive behavior change required
legislative issues and resistance
●Avoids some costly infrastructure lock-in
●Ongoing political will required
●Some costly infrastructure lock-in will occur
●Significant up-front capital costs
Evidence-based
approach
●Provides the local government with the
ability to focus on what it controls rather
than spending time and energy on levers it
cannot control
●The plan may be viewed as more localized
and decrease resistance or skepticism
●May not meet the threshold for the UNFCCC
Paris agreement
●May not be science-aligned
●Does not address global equity concerns
●Does not align with the most recent evidence
for requirements for staying within the 1.5°C
threshold
●Challenging systems-level changes required
●Extensive behavior change required
●Ongoing political will required
●Some costly infrastructure lock-in will occur
●Can create a discourse of changes being
someone else’s problem
Summary and Next Steps
The City Steering Committee has been presented with four targets options to consider. The recommendation on the City
project team and the consulting team is for stakeholder engagement on the targets with the Supplemental Input Committee
and the public to continue as planned, and for the SC to hear a summary of the stakeholder feedback before selecting a target
during the next SC meeting on December 21st, 2021.
City of Ames Climate Action Plan and
Target-Setting
Backgrounder: Carbon budgets
November 2021
Introduction
In order to prevent dangerous levels of climate change, scientists have quantified the total
greenhouse gas emissions that can be emitted in order to limit the temperature increases.
In 2017, C40 published a report titled Deadline 2020:How cities will get the job done. The
report assessed the contribution of the C40 cities to COP21 Paris Agreement’s aspirations
of limiting climate change to 1.5°C and 2°C degrees respectively. Specific greenhouse gas
(GHG) emissions reduction trajectories were identified for each of the C40 cities, as well as
potential actions to achieve those trajectories. The report concluded that the next four
years will determine whether or not the world’s megacities can achieve the reductions
required to be consistent with the Paris Agreement. Since that report, other cities around
the world have adopted C40’s approach to determining a carbon budget to determine their
emissions reduction trajectories required to limit warming to 1.5°C.
Carbon budget Overview
A carbon budget can be defined as the maximum amount of greenhouse gases that can be
emitted worldwide without increasing the global average temperature by more than 1.5°
Celsius. Using carbon budgets as a decision-making tool for managing greenhouse gas
(GHG) emissions was pioneered by the City of Oslo It has some key features worth noting:1
1 City of Oslo, “Climate Budget 2019,” 2019 [Online].Available:
https://www.klimaoslo.no/wp-content/uploads/sites/88/2019/03/Climate-Budget-2019.pdf. [Accessed: 17-Apr-2019]
●Annual targets can be derived from the pathway identified by the carbon budget for
five- or ten-year periods.
●Like a financial budget, the carbon budget provides an accountability framework for
achieving the organization’s objectives
●A carbon budget provides an overarching framework for GHG emissions
management, extending over multiple years and over all aspects of community
social and economic activity.
●When combined with effective emissions monitoring, the carbon budget also
provides a framework for reporting progress on a consistent basis from
year-to-year, while ensuring transparency and the feedback needed to make
periodic adjustments to the budget.
The latest science indicates that in order to restrict warming to less than 2°C, total CO2
emissions from all anthropogenic sources since 1870 likely need to be limited to about
2,900 GtCO2, and approximately 1,900 GtCO2 had been emitted by 2011, leaving
approximately 1,000 GtCO2, assuming a 66% degree of confidence.Restricting GHG2
emissions to 1.5° implies an even more strict budget of 400 GtCO2 as of 2016.With3
emissions since 2016, this puts the carbon budget under 200 GtCO2 in 2021.
C40’s Approach to Carbon Budgeting
C40 is a group of the largest cities in the world that recognize their influence over a large
portion of the world’s population and economies. They share their practices widely and
aspire to influence the remaining cities and national governments across the world. The
approach used to calculate a carbon budget is applicable to any city and can place the
community on an aggressive pathway to limiting climate change.
In its Deadline 2020 report, C40 used a three-step approach to identify carbon budgets for
its targeted cities:
1.Determine the global carbon budget for safe levels of warming of below 1.5°C and
2°C;
2.Identify an approach to allocate a fair portion of this budget to the C40 cities with
global equity concerns taken into consideration; and
3 Carbon countdown (2016). Carbon Brief. Analysis: Only five years left before 1.5C carbon budget is
blown. Retrieved from:
https://www.carbonbrief.org/analysis-only-five-years-left-before-one-point-five-c-budget-is-blown
2 Allen, M. R., Barros, V. R., Broome, J., Cramer,W., Christ, R., Church, J. A., ... & Edenhofer, O. (2014).
IPCC fifth assessment synthesis report-climate change 2014 synthesis report.
3.Calculate the resulting total C40 carbon budget using the chosen approach in step 2
and the relevant carbon budgets in step 1.
Under step 1, member cities in C40 were allocated a collective budget of 22 GtCO2e to
meet the 1.5 degree Celsius limit and 67 GtCO2e for the 2 degree Celsius between 2016
and 2100. All other cities were given a limit of 307 GtCO2e in the 2 degree scenario, and 97
GtCO2e in the 1.5 degree scenario as shown in figure 2 below. C40 used the global carbon
budgets with a 66% degree of confidence of limiting global temperature rises to 1.5 and 2
degrees Celsius respectively.
Figure 30: Global Carbon Budgets under the 1.5 degrees Celsius Scenario (Left) and 2 degrees Celsius scenario
(Right)4
For step 2, C40 selected the year of 2030 where member cities need to achieve 2.9 tonnes
of carbon dioxide equivalent (tCO2e) per capita, to be consistent with a 1.5 degrees Celsius
pathway.By 2050, the selected cities are required to reach 0.9 tCO2e.5
This same methodology can be extrapolated to determine the carbon budget for other
cities.
5 For the selected C40 cities, 3.2 tCO2e per capita is approximately half of the current global per capita
emissions.
4 Deadline 2020 (2017) C40 Cities. Retrieved from: https://www.c40.org/researches/deadline-2020
City of Ames
Climate Action Plan +
Target Setting
City Steering Committee:
Target Setting Overview
Nov. 16, 2021—6:00-8:00 PM
Meeting Objectives
●To inform Steering Committee members about:
○Business-as-usual (BAU) results;
○Engagement outputs to date; and
○Target options developed by SSG.
●To consult Steering Committee members about their
questions, comments, and concerns today regarding the
BAU results, engagement outputs, and target options.
Reminder
●This evening is about sharing information, asking
questions and providing feedback
●We will share how we would like to engage the community
between this evening and the next SC meeting
●At the next SC meeting, we encourage you to set a target
Meeting Agenda
●Introduction
●Engagement Update + Q&A
●Business-as-usual results + Q&A
●Target Setting Overview + Q&A
●Wrap-Up & Next Steps
Project Overview
Engagement Update
Engagement Summary to Date
●Website launched
●Community visioning exercise
●Supplemental Input Committee
●Town Hall
Project launch and business-as-usual
phase (information-sharing)
8
What makes Ames a great place to live?
1.Sense of community
2.Parks & nature
3.Services
4.Safety
5.ISU + education
9
Are there any environmental initiatives in Ames
that you think have been really successful?
1.Renewables
2.Transit
3.Parks, trees &
nature
4.Waste diversion
5.Not enough
10
Are there other problem-solving examples in
Ames that have been really effective?
1.Renewables
2.EV infrastructure
3.Transit
4.Food at First
5.Parks (Miracle Park,
Ada Hayden)
11
Are there climate action examples in other
jurisdictions that you find inspirational?
1.Iowa City
2.Des Moines
3.Illinois
4.Boulder, CO
5.Europe
12
In considering opportunities to transition to a
low carbon future, what gives Ames a unique
advantage in tackling this issue?
1.Expertise & education
2.Community involvement
3.Students & young people
4.Availability of clean
energy
5.ISU
13
If there were no constraints, what is the first
thing you would want to see happen in Ames to
tackle the issues of climate change?
1.Increase renewables
2.Lower transportation
emissions
3.Increase waste diversion
4.Net-zero by 2030
5.City design and zoning
14
What are your desired outcomes from this plan?
1.100% clean energy
2.Net-zero by 2030
3.Implementation
15
When the plan is complete what do you want
the community to look like?
1.Sustainable
2.Green
3.Equitable
Upcoming Engagement
●Community survey
●Supplemental Input Committee
outreach support
●Supplemental Input Committee Two
●Ongoing website updates
Target-setting phase (consult &
involve)
Engagement
Q+A
Business-as-Usual Results
Business-as-Usual Scenario
Assumptions
Analysis and
interpretation of data
and information
Data and
Information
Data from city and
other trusted sources
Policies and plans
approved and/or
underway
Projections
Projections for individual factors
modelled together to create a future
scenario for community energy-use
and emissions
About Scenarios
A scenario is an internally consistent view of
what the future might turn out to be - not a
forecast, but one possible future outcome; one
of many possible views of the future.
Total GHG Emissions by Sector
Total Emissions by Fuel
Total Energy Use by Sector
Electricity supply emission factors
Electricity supply 2018
Energy & Emissions Source Descriptions
Legend Description
Local energy Solar PV
RNG Renewable natural gas
Fuel oil, propane,
natural gas
Direct to consumer (residential, commercial,
industrial)
District energy ISU combined heat and power (CHP) system
Grid electricity From all utility providers
Fugitive Emissions from the production and transportation of
natural gas
26
Business-as-usual
Q+A
Target Setting Overview
Target-setting Review
29
The Process
Present the four options to the City Steering Committee
A.Target-setting briefing
B.Tonight’s presentation and opportunity for questions and comments
Present the four options to the Supplemental Input Committee
A.Target-setting briefing
B.Workshop on December 1st (to inform and to involve)
Present the four options to the public
A.Via the website, social media, press release and their access to this presentation (to inform)
B.Via a community survey (to consult)
City Steering Committee sets the target
A.Meeting on December 21st
B.With engagement outputs available for consideration
The Target Options
Science-based
(general)
Aligned with Federal
Target
Science-based
(Fair-share)
Evidence-based
Net-zero 2050 commitments
Not all targets are created equal
Science-based Target (General)
34
35
Science-based Target (general)
●45% reduction in
greenhouse emissions from
2005 levels by 2030, and
net-zero emissions by 2050.
●In line Paris Agreement and
the 2018 recommendation
from the Intergovernmental
Panel on Climate Change
●Based on staying below 2°C
and ideally 1.5°C in
warming above
pre-industrial level.
The World is not on track
37
Science-based Target (general)
Benefits
●Aligned with:
○UNFCCC Paris Agreement
○2018 IPCC recommendations
●Similar target to many other
jurisdictions
●Avoids some costly infrastructure
lock-in
●Has potential to realize co-benefits at
a local level- clean air, connected
community
Challenges
●Does not address global equity
●Does not align with the most recent
evidence for staying within 1.5°C
●Challenging systems-level changes
required
●Extensive behavior change required
●Ongoing political will required
●Some costly infrastructure lock-in will
occur
●Up-front capital costs
●Impacts of climate change
Aligned with Federal Target
38
39
Aligned with Federal Target
●50-52% reduction in
greenhouse emissions from
2005 levels by 2030, and
net-zero emissions by 2050.
●In line with the federal
emissions reduction target
announced in April 2021.
●Based on the United States’
Nationally Determined
Contribution in line with
Article 4 of the Paris
Agreement.
40
Nationally Determined Contributions
●Non-binding
●Self-imposed
●Climate neutrality by 2050
●Minimum 2°C aligned
●Based on a baseline figure
●Adaptation considerations
●Adjusting financial flows to align with
reducing GHG emissions
41
Federal Commitments
●100% carbon-free electricity by 2035
●Supporting energy efficiency upgrades and
electrification in buildings
●Reducing carbon pollution from the
transportation sector
●Industry decarbonization
●Agriculture decarbonization and land
management
42
Source: United States | Energy Policy Solutions
43
Federal Target
Benefits
●Aligned with:
○UNFCCC Paris Agreement
○2018 IPCC recommendations
●Similar target to many other
jurisdictions (local and national)
●Avoids some costly infrastructure
lock-in
●Has potential to realize some
co-benefits at a local level (e.g. clean
air)
Challenges
●Does not address global equity
●Does not align with the most recent
evidence for staying within 1.5°C
●Challenging systems-level changes
required
●Extensive behavior change required
●Ongoing political will required
●Some costly infrastructure lock-in will
occur
●Up-front capital costs
●Impacts of climate change
Science-based Target: Carbon Budget + Equity
44
45
Science-based Target (Carbon Budget + Equity)
●83% reduction in
greenhouse emissions from
by 2030, and net-zero
emissions by 2050.
●In line with the
Science-Based Targets
Network & C40 Climate
Leadership
recommendations
●Based on staying within 1.5°
C in warming while
considering equity.
46
Carbon Budget + Equity Principles
1.Responsibility
2.Capacity
3.Intergenerational justice
Equitable distribution
48
Carbon Budget
The maximum amount of greenhouse
gases that can be emitted world-wide
without increasing the global average
temperature more than 1.5° Celsius.
Pre-industrial:
2,500 GtCO2e
How much is the global carbon budget?
2020:
296 GTCO2e
Carbon Budget - Ames (2018)
The carbon
deficit (aka “the
opportunities”)
30 MtCO2e
~9900
ktCo2e
Carbon Budget Opportunities Example
135 MtCO2e
The opportunities
This chart is an example and does not represent Ames
52
Science-based Target (Carbon Budget + Equity)
Benefits
●Aligned with:
○UNFCCC Paris Agreement
○2018 IPCC recommendations
○Science-based Target Network
●Avoids costly infrastructure lock-in
●Maximizes co-benefits - equity, cleaner
air, more connected communities
●Has potential to realize co-benefits at
a local level sooner
Challenges
●Up-front capital costs
●Challenging systems-level changes
required
●Extensive behavior change required
●Ongoing political will required
●Potential for resistance due to quick,
transformative changes
Evidence-based Target
53
54
Evidence-based Target
●45% reduction in
greenhouse emissions from
2005 levels by 2030, and
net-zero emissions by 2050.
●In line Paris Agreement and
2018 pathway identified by
the Intergovernmental
Panel on Climate Change
●Based on staying below 2°C
and ideally 1.5°C in
warming above
pre-industrial level.
55
Evidence-based Target Example
56
Evidence-based Target
Benefits
●Provides the local government with
the ability to focus on what it controls
rather than spending time and energy
on levers it cannot control
●Change may be accepted because it
was ‘locally-built’
●May avoid costly infrastructure lock-in
●Has potential to realize co-benefits
Challenges
●May not meet the threshold for the
UNFCCC Paris agreement
●May not be science-aligned
●Does not address global equity
●Challenging systems-level changes
required
●Extensive behavior change required
●Ongoing political will required
●Some costly infrastructure lock-in will
occur
●Can create a discourse of changes
being someone else’s problem
Targets Summary
57
58
Targets Compared
*Evidence-based not shown
because it needs to be
modeled first
Net-Zero by 2050 Goals
Des Moines, IA
Iowa City, IA (approaching net-zero)
Sioux Fall, SD
Bloomington, IN
Lawrence, KS (100% renewable by 2050)
Madison, WI
LaCrosse, WI
Middleton, WI
Your Neighbors
Target Setting
Q+A
Wrap Up + Next Steps
Thank You!