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Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports (2021)

Chapter: Chapter 3 - Setting Emissions Goals, Baselines, and Targets

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Suggested Citation:"Chapter 3 - Setting Emissions Goals, Baselines, and Targets." National Academies of Sciences, Engineering, and Medicine. 2021. Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports. Washington, DC: The National Academies Press. doi: 10.17226/25677.
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Suggested Citation:"Chapter 3 - Setting Emissions Goals, Baselines, and Targets." National Academies of Sciences, Engineering, and Medicine. 2021. Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports. Washington, DC: The National Academies Press. doi: 10.17226/25677.
×
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Page 31
Suggested Citation:"Chapter 3 - Setting Emissions Goals, Baselines, and Targets." National Academies of Sciences, Engineering, and Medicine. 2021. Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports. Washington, DC: The National Academies Press. doi: 10.17226/25677.
×
Page 31
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Suggested Citation:"Chapter 3 - Setting Emissions Goals, Baselines, and Targets." National Academies of Sciences, Engineering, and Medicine. 2021. Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports. Washington, DC: The National Academies Press. doi: 10.17226/25677.
×
Page 32
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Suggested Citation:"Chapter 3 - Setting Emissions Goals, Baselines, and Targets." National Academies of Sciences, Engineering, and Medicine. 2021. Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports. Washington, DC: The National Academies Press. doi: 10.17226/25677.
×
Page 33

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29   Setting Emissions Goals, Baselines, and Targets This chapter describes a 5-step process for setting an emissions goal, based on guidance from the Greenhouse Gas Protocol on emissions mitigation goal setting (WRI 2014). As with other chapters, steps presented in this chapter, shown in Figure 10, should be performed iteratively and in conjunction with the other steps. C H A P T E R 3 Section 3.1: Conduct Greenhouse Gas Inventory Section 3.3: Choose Goal Type Section 3.2: Define Goal Boundary Section 3.4: Define Target Years Section 3.5: Define Allowable Emissions in Target Years Figure 10. Steps for setting emissions goals, baselines, and targets. 3.1 Conduct Greenhouse Gas Inventory A first step to setting an emissions goal is to conduct a GHG inventory—that is, an accounting of all emission sources and sinks from airport activities. For an airport, this involves the following steps (see ACRP Report 11 and ACRP Synthesis 85 for additional guidance): 1. Review background information, including understanding any new protocols or standards that have been implemented since the airport’s prior emissions inventory; 2. Collect energy and emissions documentation, such as utility bills, fuel logs, airport activity levels, and other similar information; 3. Calculate emissions at the airport using tools, calculators, and established processes—a recommended tool for U.S. airports is the Airport Carbon and Emissions Reporting Tool (ACERT); and 4. Develop an inventory report, which clearly communicates emis- sions trends with the public. Resources that provide detailed information on how to conduct a GHG inventory are included in Table 8. Additional Benefits of Collecting Emissions and Energy Data Collecting data for a GHG inventory can present some initial hurdles regarding internal processes and figuring out what departments hold what information. However, communication across departments to collect this information and having these departments talk to each other can offer benefits. For example, Austin-Bergstrom International Airport saved about $1 million just by tracking and more closely monitoring its utility bills.

30 Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports Using ACERT ACI developed the Airport Carbon and Emissions Reporting Tool (ACERT), a free, Excel- based tool for airports to develop carbon emissions inventories. The tool is supported by ACI staff and is regularly updated. At the time of this guidebook’s publication, version 6.0 is available. ACERT is consistent with the internationally recognized Greenhouse Gas Protocol. The tool and a user manual can be downloaded from ACI’s website. ACERT can be used to develop emissions inventories for Scope 1, Scope 2, and Scope 3 and is also accepted for purposes of ACA. To use the tool, airports should read the user manual and the “Intro” tab in the Excel document prior to beginning the calculations to understand the data collection requirements. Airports should further confirm that the emissions factors built into the tool are the most accu- rate for the airport’s location or should manually enter the correct emission factor. Though the tool is intended for use by staff with no prior inventory development experience, it is recom- mended that the results be reviewed closely for accuracy. 3.2 Define Goal Boundary The next step is to define the goal boundary—that is, the geographic area, emission type, scope, timeline, and airport activities that will be within the goal. This boundary may differ from the boundary in the inventory and therefore is a separate step in Chapter 3. For example, the inventory may include all airport-owned (including tenant-operated) spaces, but the emissions goal may include only airport-owned and operated spaces. How the boundary is defined can have a significant impact on achieving the mitigation goal as well as on the opportunities avail- able for achieving that goal. Note that the airport should consider and harmonize its emissions goal with the goals of the surrounding regional governments. Another important note is that setting soft goals can sometimes be appropriate, especially if they are oriented toward the long term and their purpose is to set a specific intent. Soft goals are not as measurable or quantifiable as fixed goals that set the time frame, emission type, and scope and that are generally actionable. But soft goals can be acceptable if elements such as time frame cannot be ascertained at the time goals are set. One example is if an airport sets a long-term goal to achieve zero-emissions but cannot yet set a date for achieving it. Tool and Resource Author Description ACRP Report 11: Guidebook on Preparing Airport Greenhouse Gas Emissions Inventories Kim et al. (2009) This resource guide is designed to help airport operators and others prepare an airport-specific inventory of GHG emissions. Airport Carbon and Emissions Reporting Tool (ACERT) v. 6.0 ACI (2019) This tool provides a method to measure an airport’s GHG emissions by source and generates a comprehensive GHG emissions inventory report that highlights the airport’s performance based on emissions intensity. Guidance Manual: Airport Greenhouse Gas Emissions Management ACI (2009) This manual provides airport operators guidance on managing GHG emissions, including how to conduct a GHG emissions inventory and which airport sources to include. The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard WBCSD and WRI (2015) This widely adopted standard provides step-by-step guidance for companies and other organizations to use when quantifying and reporting their GHG emissions. Table 8. Tools and resources for conducting greenhouse gas inventory.

Setting Emissions Goals, Baselines, and Targets 31   3.3 Choose Goal Type All emissions goals share the same underlying objective—to reduce emissions—yet they can differ materially in how they are worded. An airport should seek to answer the four questions shown in Table 9 along with possible answers and examples. How best to answer these questions depends on airport-specific preferences, including the desired level of transparency, simplicity, and benchmarking desired. If the airport also uses a voluntary emission reduction and reporting program, the program may include requirements for the goal. 3.4 Define Target Years Choosing a target year—that is, the year in which an airport needs to meet its emissions goal—involves choosing a base year (if applicable), deciding whether to adopt a single-year or multiyear goal, and choosing the target year. These three steps are described below. Choose Base Year A base year is the reference year from which progress toward a goal is measured. Goals that go to zero (e.g., net zero, zero emission) do not need a base year since zero implies an absolute, not relative, reduction. For goals with a base year, the choice depends on the desired strin- gency of the goal. For example, an 80% reduction relative to 2005 levels may be much easier to achieve than an 80% reduction relative to 2015 levels if emissions grew in those 10 years. Another consideration is that having a single base year (e.g., 2005 levels) simplifies the process for goal setting, tracking, and reporting. However, caution should be taken if using a single base year because of year-to-year variations in emissions. Some organizations, therefore, average across an emissions period that uses multiple years. As of the writing of this guide- book, many airports are opting to set targets of carbon neutrality and carbon free, which do not require a base year. Choose Whether to Adopt a Single Target or Set of Targets Adopting a single target year may be simpler to convey to airport stakeholders, but multiple years may be advantageous from a climate change perspective to avoid situations in Question Options Example Reduction in what? Emissions 50% reduction in metric tons of CO2 by 2030 Emissions intensity 50% reduction in CO2 per passenger by 2030 Relative to what? Historical year 50% reduction in metric tons of CO2 by 2030, relative to 1990 levels Baseline scenario 50% reduction in metric tons of CO2 by 2030, relative to the baseline scenario No reference Carbon neutral by 2030 Reduction or stabilization? Reduction in emissions 50% reduction in metric tons of CO2 by 2030 Stabilization of emissions No growth in CO2 emissions after 2025 Which gases? CO2 emissions 50% reduction in metric tons of CO2 GHG emissions 50% reduction in metric tons of gases regulated under the Kyoto Protocol: CO2, CH4, N2O, HFCs, PFCs, SF6, and NF3 Table 9. Questions to answer when defining airport emissions goal.

32 Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports which an airport reduces emissions shortly before a target year. An example of Seattle-Tacoma International Airport’s multiyear targets, broken down by emission scope, is shown in the box. Indeed, the impact on climate change from airport activities is closely related to the total cumulative amount of GHG emissions released over time. If users of this guidebook have reasons to avoid multiple targets, then the minimum best practice is to set milestone years, which are less formal than official targets but still allow an airport to assess progress toward an ultimate emissions goal. Figure 11 shows a conceptual diagram of an emissions reduction target. Three pathways are shown that achieve the eventual emissions target: a linear reduction schedule, a fast-tracked reduction schedule, and a delayed reduction scheduled. Though all paths achieve the target, the fast-tracked path will have the fewest cumulative emissions by the target year, whereas the delayed path will have the highest. Cumulative (in addition to annual) emissions are an important consideration for airports interested in true contributions to climate change mitigation. Because cumulative emissions are what influences climate change, and because GHGs are long-lived, earlier action is preferable: faster reduc- tions provide benefits over a greater duration. Choose the Target Year The choice of the target year or years depends primarily on the desired stringency of the goal. Obviously, for a given level of emissions reduction, a nearer-term goal (e.g., 2030) does more for climate change mitigation than a longer-term goal (e.g., 2050). At the same time, a longer- term goal may allow an adequate time horizon to conduct the necessary capital planning and expenditures. Delayed Path Fast-Tracked Path Linear Path Goal Period Year 6 Target Years = Interim Target or Milestone Allowable emissions in the target period Year 4Year 2Base Year GH G Em iss io ns (M tC O 2e ) Figure 11. Delayed (top), linear (middle), and fast-tracked (bottom) emissions reduction schedules. Century Agenda Strategic Objectives of the Port of Seattle (Seattle-Tacoma International Airport) The Port of Seattle’s Century Agenda Strategic Objectives are an example of ambitious GHG goals (Port of Seattle 2017). • Scope 1 and Scope 2 emissions shall be: – 15% below 2005 levels by 2020. – 50% below 2005 levels by 2030. – Carbon neutral by 2050 or carbon negative by 2050. • Scope 3 emissions shall be: – 50% below 2007 levels by 2030. – 80% below 2007 levels by 2050.

Setting Emissions Goals, Baselines, and Targets 33   3.5 Define Allowable Emissions in Target Years A final step is to determine the maximum quantity of emissions in the target year. Best prac- tices for developing goals include being organized, ambitious yet reasonable, and concrete (EPA 2019). These three practices are summarized here in the context of an airport. Be Organized • Goals should be clear and concise. To best develop buy-in and make them understandable, a short direct statement is usually better. • Multiple tiers of goals can be useful. The highest tier might be qualitative and framed to relate to valued stakeholders. An example is to mitigate the airport’s impacts to climate change and thus climate change’s impacts on our communities. Subsequent tiers should be more specific and quantitative. Be Ambitious and Reasonable • Goals should inspire airport staff and community members to act but not be so ambitious that they intimidate. Some goals could be more aggressive to complement more achievable ones, or each goal could seek to meet an ambitious yet reasonable balance. • Consider including goals for which the airport has already made some progress. This early progress can help accelerate the initial momentum and encourage further changes. Be Concrete • Qualitative goals can be useful from a communications and buy-in perspective, but quantita- tive, measurable goals are most useful for actually driving emissions reductions. An additional consideration when setting the level of an emissions goal is to make the goal a science-based target (SBT). A target is science-based if it is developed in line with the scale of decarbonization necessary to keep the average global temperature increase below 2°C from preindustrial levels, as discussed in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). The SBT Initiative (SBTi) is a joint venture between CDP, World Resources Institute, the World-Wide Fund for Nature, and the United Nations Global Compact and is dedicated to encouraging private businesses to set and promote science-based decarbonization goals. As of January 2021, there are 604 businesses registered and taking action toward reducing GHG emissions with the SBTi. The latest guidance from the SBTi recommends setting temperature targets at either 1.5°C or well below 2°C from preindustrial levels. Currently, the only airports or port authorities in the world that are registered with the SBTi are the Port Authority of New York and New Jersey (PANYNJ), Auckland International Airport, and Heathrow International Airport. For PANYNJ, for example, the SBT is a 35% reduction in GHGs by 2025 and a long-term goal of 80% by 2050 (CDP et al. 2020).

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Airports worldwide are setting aggressive zero- or low-emissions targets. To meet these targets, airports are deploying new strategies, adopting innovative financing mechanisms, and harnessing the collective influence of voluntary emissions and reporting programs. In tandem, new and affordable zero- or low-emissions technologies are rapidly becoming available at airports.

The TRB Airport Cooperative Research Program's pre-publication draft of ACRP Research Report 220: Guidebook for Developing a Zero- or Low-Emissions Roadmap at Airports covers all steps of roadmap development, from start to finish, using conceptual diagrams, examples, best practices, and links to external tools and resources. While the main focus of this Guidebook is airport‐controlled greenhouse gas (GHG) emissions, it provides discussion about airport‐influenced emissions from airlines, concessionaires, and passengers.

Whereas other guidebooks and reference material provide airports with information on emissions mitigation and management (for example, the Federal Aviation Administration’s Airport Carbon Emissions Reduction, ACRP Report 11: Guidebook on Preparing Airport Greenhouse Gas Emissions Inventories, and the Airport Council International’s Guidance Manual: Airport Greenhouse Gas Emissions Management), this Guidebook articulates steps for creating an airport‐specific emissions roadmap.

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