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Measuring Scope 3 Emissions from Waste at Stanford University

Annabelle Bardenheier, Scope 3 Emissions Analyst

Stanford University

CURC Webinar, April 21, 2022

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Agenda

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Scope 3 Emissions Refresher
Data Collection & Calculation Basics
Overview of Emissions Calculation Options
Waste Transport Emissions
Special considerations around Waste
Q&A

In this session, I will give everyone an overview of what Scope 3 emissions are, and how the waste stream creates the emissions we’d like to measure.

Then, I’d like to overview the whole process with you all, starting with what kind of data we used, and a method we are using to estimate the emissions from waste. I’m also going to break down our process for estimating emissions from transportation of our waste so you all can replicate that process if you are interested.

Additionally, I will touch a bit on how we try to assess emissions from waste in a holistic way to promote synergy with other sustainability and environmental justice goals, and other insights gained from Stanford’s initial steps in this work.

Then, I’m happy to take any questions that the attendees may have about our work or on anything that would be helpful to discuss.

~2 minutes long intro.

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Refresher: Scope 3 Emissions

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Definitions

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Scope 1: direct on-premise fossil fuel combustion and other direct greenhouse gas emissions
Scope 2: direct off-premise emissions from purchased grid electricity
Scope 3: indirect emissions from sources that occur as a result of an institution’s operations but are from sources not owned or directly controlled by the institution. There are 15 categories of Scope 3 emissions.

Stanford will have reduced Scope 1 & 2 emissions by 80% as of 2022 from its 2011 baseline.

Stanford also has a pathway for 100% reduction of Scopes 1 & 2 emissions.

I’m hoping that this slide either refreshes your knowledge on greenhouse gas accounting and the 3 scopes, or, if you haven’t heard about how greenhouse gas accounting is done according to these scopes, give you the basics you need to know today. So scopes 1 and 2 are meant to reflect all of the emissions associated with your gas consumption, and your electricity consumption. So, natural gas being burned to heat up a building, and the electricity being produced to power that building comes from a power plant who’s burning that fuel, perhaps a mix of natural gas and a few other things. Stanford has a pretty good understanding of these parts of its footprint. In fact, it’s already reduced its scope 1 and 2 emissions by 80% as of 2022 from its 2011 baseline.

We’ve really started getting work on Scope 3, which is a bit different conceptually so it requires a slightly different approach. In Scope 3, we want to quantify all of the emissions in our supply chain, like the emissions embodied in all of the goods we purchase, and that are generated by the waste we produce. This scope is very important because it captures

ADD DETAIL: importance of Scope 3. Scope 3 is other people’s scopes 1 and 2. leverage position to encourage efficiency outside of our realm. We are able to influence our emissions and we have leverage over those emissions even if we are not the ones emitting.

2 minutes

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Overview of 3 scopes of greenhouse gas emissions

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Business Travel

Upstream Leased Assets

Employee

Commuting

Waste

Purchased Goods

Capital Goods

Fuel & Energy Related Activities

Processing of Sold Products

Investments

End of Life of Sold Products

Downstream Transportation of Sold Products

Downstream Leased Assets

Upstream Transportation of Sold Products

Franchises

Use of Sold Products

Company

Facilities

Company

Vehicles

Scope 1 Emissions

Upstream Scope 3

Emissions

Upstream Activities

Reporting Company

Downstream Activities

Purchased

Electricity

Scope 2

Emissions

Downstream Scope 3

Emissions

Scopes 1, 2, and 3 are all outlined here. There are commonly 15 categories of Scope 3 emissions categories, which are shown above in relation to Scope 1 as well as Scope 2 emissions. So in the middle here we have the pink arrow pointing upwards, and that reflects Scope 1. Any gas that’s being burned on your site to heat up your buildings, and any gas that’s being used to fuel your owned fleet is involved in Scope 1. On the top left, the shorter arrow represents Scope 2 emissions which reflect what emissions were produced by a power plant in order to get you your electricity. Tracking the gas and electricity you purchase is relatively easy, since all institutions are keeping a record of these purchases. Everything else on the curved arrows is a bit harder to account for. These are scope 3 emissions, the emissions associated with everything you buy, transporting everything you buy, the emissions from your employees commuting to work, and the emissions associated with people going on business trips just to name a few. Scope 3 emissions help to account for the full lifecycle of products and services, from the point of resources extraction all the way through to the end-of-life of those resources. About half the Scope 3 emissions are considered ‘upstream’ of the reporting institution while the other half are downstream.

For many organizations/institutions, the total emissions from Scope 3 can be much larger than Scopes 1 & 2. It is important to Stanford to begin to calculate these emissions so it can better understand the sources of the emissions and related strategies to reduce them.

~3 minutes (5 minutes total so far)

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Data Collection & Calculation Basics

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The following summarizes the basic process for calculating any emissions associated with the University.

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Collect Stanford Data

Apply Emissions Factors

Supplier-specific: emissions based on custom data for each supplier (i.e. a waste hauler publishes that its service produces 0.30 MT carbon for every .1 short ton hauled)

Spend-based: emissions based on dollars spent by the university

(i.e. $700k spent on Landfill hauling)

Unit-based: emissions based on the most applicable unit

(i.e. short tons of plastic recycled)

Preferable: Unit-based (lbs, kg)

Suitable: Spend $

When performing carbon footprinting on any of our activities, we perform the following process. First, we collect the best quality data we have. Either we can collect the dollars spent on an activity, such as $700,000 spenton landfill hauling, or the weight of a good. As a general rule of thumb, unit based or physical weights of goods, what’s in the orange here such as short tons of plastic recycled, is preferred over just the price paid to haul that waste. Since emissions are really the result of a chemical and physical process, we want to know how much physical material is leaving our facilities and how it’s going to be disposed of or treated. Unfortunately, many Scope 3 categories are hard to track down at a physical level. Most of the time, institutions just have the dollars they’ve spent on a good, and have less documentation about quantities. Getting an estimate of that physical weight is ideal. Based on either the spend we have or the physical weights we have, we can choose an appropriate set of emission factors. I would like to focus on the orange box primarily here, and then the purple one secondarily. There are many publicly available datasets from reputable institutions like the EPA that publish the average emissions per pound of each kind of waste, so you can rely on that research for your emission factor estimates. In the purple box, we have the supplier –specific emission factors, which is something I see far less often, and that’s used in a case where a company has published their average emission factors. Like for example they may publish that its service produces .30 MT carbon for every 10^th of a short ton hauled. I see this less often because most companies haven’t had the resources to calculate their emissions, and of course we’d want to have a third party verify the emissions they report to us so we know it’s accurate. For the purposes of this presentation, I want to really focus on that unit or physical based emission factors which are here in orange. This is really the ideal here. 45 sec-1min

Change supplier specific example: just add one sentence, get rid of extra explanation

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We chose the Unit-based approach since it matched our highest level of data quality. Weights of wastes were provided by our Hauler.

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Collect Stanford Data

Apply Emissions Factors

Supplier-specific: emissions based on custom data for each supplier

Spend-based: emissions based on dollars spent by the university

Unit-based: emissions based on the most applicable unit

(i.e. short tons of plastic recycled)

For waste, collect physical weight of waste types that go into each waste stream

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Example data:

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Material	Waste Stream	Weight (short tons)
Aluminum Cans	Recycle	4,000
MSW	Landfill	1,000
Yard Trimmings	Compost	1,000
Food scraps	Compost	1,500

Data above is hypothetical and for example only. Real waste weight data was provided by Stanford’s waste-haulers.

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Waste Reduction Model (WARM) – currently ver. 15

Calculation: EPA-published Tool

I’m going to be focusing on a really commonly used and respected tool published by the EPA called WARM. WARM is short for Waste Reduction model. WARM is a tool that estimates the potential GHG emissions, energy savings and economic impacts of baseline and alternative waste management practices, including source reduction, recycling, combustion, composting, anaerobic digestion, and landfilling. The model calculates emissions, energy units and economic factors across a wide range of material types commonly found in municipal solid waste in the following categories:

Metric tons of carbon dioxide equivalent (MTCO2E),
Energy units (million British Thermal Unit - BTU),
Labor hours,
Wages ($), and
Taxes ($).

Of course what we’re really focusing on today is metric tons of carbon dioxide equivalent, but it’s worth mentioning that other aspects of the waste stream are considered, and it’s really designed to help institutions compare waste options.

Next I’ll dive a bit into the key value adds of this tool before giving you a preview of how to use it.

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WARM by EPA

Key Value Adds of Tool:

Credible (as created by the epa)
Transparent (significant documentation of sources and calculations)
Holistic (assesses net carbon impacts of entire waste-life cycle)
Allows multiple scenarios to be compared

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Source URL: https://www.epa.gov/sites/default/files/2019-06/documents/warm-users-guide-excel_v15_may2019.pdf

Moving on to the key value adds of the tool. The value adds are then that it’s credible, since it’s released and maintained by the EPA, and there’s significant transparency since there’s a lot of publicly available documentation to the tool. There are chapters on the overall basics of the tool and even chapters online about specific waste streams and waste types.

Another factor is that this tool doesn’t just calculate emissions associated with the products through processing. If we were just thinking about emissions that are released when a bottle is recycled, of course there are some emissions associated with transporting that plastic bottle and for firing up the plant that is performing the recycling. In that approach, pretty much every material is going to be producing emissions after leaving your site. In this tool, the greater product life cycle is taken into account, and includes a consideration of the potential greenhouse gases the waste is displacing. For example, recycling an aluminum can will emit greenhouse gases as its being processed and turned in to other products, but this process emits way less than what it would take to harvest new aluminum from the earth and process it into a new product, so there are additional savings that you are credited in the accounting. So in other words, the results you’re going to get are going to be reflective of how emissive your choices are as compared to other options for that waste type.

One of the interesting aspects of in this option is that it allows you to indicate a “baseline” waste stream set of practices, and allows you to present alternative scenarios so that you can compare the outcomes. This can be particularly helpful if you’re thinking about how different waste management choices may impact your greenhouse gas reduction goals. Say for example you’re introducing an organics composting program, you can model what the current emissions would be if you currently send all your food waste to landfill, and you can model what would happen if you were to send those all to be composted. So that’s why this tool is really beneficial for decisionmakers.

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WARM by EPA

Key Steps:

Review warm model published guidance at https://www.epa.gov/warm/documentation-chapters-greenhouse-gas-emission-energy-and-economic-factors-used-waste

Download and open the excel version of the tool at https://www.epa.gov/warm/versions-waste-reduction-model-warm#15

Determine current footprint using “baseline” data input, or compare scenarios by entering different data in “baseline” and ‘alternative” scenarios

Get results!

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Source URL: https://www.epa.gov/sites/default/files/2019-06/documents/warm-users-guide-excel_v15_may2019.pdf

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Tool Preview

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Example data from earlier to use in WARM

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Material	Waste Stream	Weight (short tons)
Aluminum Cans	Recycle	4,000
MSW	Landfill	1,000
Yard Trimmings	Compost	1,000
Food scraps	Compost	1,500

Data above is hypothetical and for example only, real waste volume data was provided by Stanford’s waste-haulers.

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WARM by EPA

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As you can see here, I’ve decided to play with two scenarios. On the top, I’ve input all the waste generated in the previous side as going to landfill. This is just a baseline hypothetical I’m using here for illustration. Based on everything going to landfill, there’s an estimated emissions of 935 metric tons of CO2 equivalent. You can see that pretty much every value has a positive emissions impact, since they’re expected to produce greenhouse gas emissions in the landfill. Food waste has a positive emissions output and this is can be explained by the fact that food scraps contain a lot of moisture, and the tool categorizes this material as going under “wet digestion.” Wet digestion includes anaerobic digestion which produces a lot of methane, which is a very potent greenhouse gas. Yard trimmings, however, are very dry organic matter, so the tool considers it as undergoing “dry decomposition.” This dry decomposition doesn’t produce any gases out of the short-term carbon cycle like methane, and is considered a carbon sink, since there is carbon being sequestered into the ground.

On the bottom, I’ve input all the waste in their respective streams as indicated on the previous slide. Specifically, the organics have been composted and the aluminum cans have been recycled. This leads the WARM model to produce a negative input value, as it takes into account all of the avoided emissions from things like harvesting and refining new virgin aluminum material to be put into cans, and the methane emissions reductions from food waste not being sent to landfill. So from this example, you can see the reductions impact of your proposed scenario. You can set the baseline as your current waste stream output, and consider what the impacts would be if you were to make those changes.

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Emissions from Transporting Waste

EXAMPLE CALCULATIONS

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Calculating emissions from transporting your waste: example

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Processing Facility	Waste Type	Trips	Round Trip Mileage	Total Miles Traveled
Facility A	Recycling	178	82.2	14,632
Facility B	Landfill	1331	37.4	49,779
Facility C	Landfill	2	48.6	97
Facility D	Composting	121	30	3,630
Facility E	Composting	649	37.4	24,273
Facility F	Recycling	345	48.6	16,767
Facility G	Landfill	3	59.8	179
Facility H	Recycling	117	49	5,733
Facility I	Recycling	12	27.2	326
Facility J	Composting	349	7	2,443
Facility K	Recycling	2	61.8	124
Facility L	Landfill	304	32.4	9,850
Facility M	Recycling	1859	32.4	60,232

Waste Stream	Total Miles Traveled by Truck in CY
Landfill	59,905.60
Recycling	97,813.20
Composting	30,345.60

Source: EPA Emission Factor Hub, 2022

Emission Factor	Kg CO2e/Vehicle-Mile	MT CO2e/Vehicle Mile
Medium-And-Heavy Duty Truck	1.45	0.00145

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Calculating emissions from transporting your waste: example using data from one Stanford Waste Hauler

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Waste Stream	Total Miles Traveled by Truck in CY	MT CO2e/Vehicle Mile	MT CO2e (Total Miles * MT CO2e/Vehicle Mile)
Landfill	59,905.60	0.00145	86.86
Recycling	97,813.20	0.00145	141.83
Composting	30,345.60	0.00145	44.00

Source: EPA Emission Factor Hub, 2022

Emission Factor	Kg CO2e/Vehicle-Mile	MT CO2e/Vehicle Mile
Medium-And-Heavy Duty Truck	1.45	0.00145

Total	272.69 MT CO2e

Equation: Metric Tons of CO2e = Vehicle-Miles * (MT CO2e/Vehicle-Mile)

Our value ended up being roughly 20% of our total landfill footprint!

So here I’ll walk through the calculations. I have on the top the equation that we’ll be using. It consists of just the miles traveled being multiplied by the average emissions per vehicle mile to get the total emissions. I’m using the EPA emission factor for Medium and Heavy Duty Trucks as seen on the table in the left, and I took this from the EPA’s most recent set of emission factors that were published a few days ago.

In the table on the right, I’ve broken down the mileage for each waste stream so we can have a look at the transport emissions by category, like recycling, landfill, and compost. I just multiplied the two columns in the middle of this table, so miles times the average metric tons of CO2e per vehicle mile, and I got the values on the far right column. So for landfill, I multiplied that 59,000 miles by th e0.00145 metric tons of CO2 to get that value on the right of 86.86. So really quite simple, all you need is the mileage and a number that estimates the average emissions per mile.

On the bottom I have that all of our waste streams transportation amounts to 273 metric tons of CO2e. For context, that’s around 1/5 of our total landfill footprint. It’s not a trivial amount, so you may be interested in finding out what your transportation emissions are, and how you can hone in on transportation as a specific aspect of the footprint in your strategizing. Reducing your load might help you take fewer trips, and of course the goal is to take as few trips as possible to minimize mileage. You may also consider alternative fuels for your transportation to reduce that emission factor provided by the EPA. The default gas being used in this example is diesel, but there are emerging alternatives.

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Calculating emissions from transporting your waste: other fuel/vehicle emission factors available

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Source: EPA Emission Factor Hub, 2022

Vehicle Type	Fuel Type	Vehicle Year	CH₄Factor �(g / mile)	N₂O Factor �(g / mile)
Light-Duty Trucks	Diesel	1960-1982	0.0011	0.0017
		1983-2006	0.0009	0.0014
		2007-2019	0.0290	0.0214
Medium- and Heavy-Duty Vehicles	Diesel	1960-2006	0.0051	0.0048
Medium- and Heavy-Duty Vehicles	Diesel	2007-2019	0.0095	0.0431
Light-Duty Cars	Methanol		0.0080	0.0050
	Ethanol		0.0080	0.0050
	CNG		0.0810	0.0050
	LPG		0.0080	0.0050
	Biodiesel		0.0300	0.0190
Light-Duty Trucks	Ethanol		0.0120	0.0090
	CNG		0.1210	0.0090
	LPG		0.0120	0.0120
	LNG		0.1210	0.0090
	Biodiesel		0.0290	0.0210
Medium-Duty Trucks	CNG		4.200	0.0010
	LPG		0.0140	0.0340
	LNG		4.200	0.0010
	Biodiesel		0.0090	0.0430
Heavy-Duty Trucks	Methanol		0.0750	0.0280
	Ethanol		0.0750	0.0280
	CNG		3.70	0.0010
	LPG		0.0130	0.0260
	LNG		3.70	0.0010
	Biodiesel		0.0090	0.0430

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Reasons to calculate your own emissions related to transportation

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Your calculations include the exact distances traveled, rather than country-wide average estimates

Higher Accuracy than using transportation assumptions in WARM model

Different emission factors can be used to model alternative transportation options (e.g. using electric vehicles or biofuel) and assess changes to the transportation footprint

Allows consideration of alternative transportation methods

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Additional Considerations Around Waste

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System-wide thinking: Challenges

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Credits for avoided emissions from recycling and composting can incentivize increasing recycling and composting volume, which may disincentivize reducing & reusing
Quantify emissions from “Purchased Goods & Services” and keep those emissions in mind; aim to reduce and reuse purchases as much as possible

Reducing & Reusing

Each management option triggers some environmental concerns, including air emissions, potential groundwater and surface water contamination, and soil contamination.
Examine how chosen and proposed changes to waste disposal treatments will affect their surrounding communities, and aim to minimize impact

Environmental Justice

Here are some special considerations I’d like to talk about that are some challenges. As we discussed earlier, negative carbon emissions as shown in the warm model show how your actions in recycling and composting are leading to fewer carbon emissions than alternatives. However, if you take that information at face value, you may be incentivized to maximize your compost and recycling output weight to give yourself the highest amount of negative credits. However, this may take away from efforts to reduce and reuse and minimize the overall load of the waste generation. Of course, ideally, we’d like to purchase less, which would decrease the footprint in purchased goods and services, and reuse materials to use them as efficiently as possible. So, reducing the overall volume by purchasing less and reusing more is definitely key here and important to remember in the way you contextualize your results and set your goals.

Second, I’d like to talk about some environmental justice concerns. Each management option triggers some environmental concerns, like air emissions or potential groundwater and surface water contamination. This disproportionately affects any community near disposal sites, and historically these have been communities that have fewer resources than others which compounds the associated impact on their health and wellbeing. Of course the the environmental consequences associated with each waste management option with regards to each waste stream vary, but we can’t forget these considerations when we’re thinking about changing destinations of our waste streams.

~3 minutes

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System-wide thinking: Challenges

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Many goods may be marked as recyclable but are not accepted as recyclable goods by the local recycling plant
Connect with local recycling facilities to learn what kinds of waste are accepted (& advocate for more materials to be added to the list)
Educate the University community about which goods are recyclable to minimize contamination

Minimizing contamination

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System-wide thinking: opportunities

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Waste data can help identify excess purchased goods 🡪 reduce volume purchased
Fewer items purchased can mean fewer embodied emissions (and $ savings)
Fewer trips to waste disposal facilities means fewer transportation-related emissions (and $ savings)

Lowering purchase volumes

Examine which waste products lead to high emissions
Look for substitute products with less embodied carbon (upstream) and less emissions as they are disposed of (downstream)

Substituting products

There are a lot of cross cutting synergies associated with the task of quantifying Scope 3 emissions from waste. Although waste is a discrete Scope 3 category, addressing the emissions in this category also has several impacts for the institution from an emissions standpoint and a financial one. The first one I’m going to talk about is how your waste data can help you set goals to reduce the goods purchased. I’m going to focus on produce here as an example. Say your organization purchases 100 pounds of apples and learns that 20 pounds ended up going bad and ended up as food waste. Perhaps this insight could lead the procurement group to decide to purchase closer to 80 pounds to minimize waste. Then, not only are 20 pounds of apples not going into the waste stream, but you don’t have to account for all of the upstream emissions associated with you buying those 20 apples, and you save the money from not buying them.

Another benefit of being acquainted with your waste stream is in helping you think about alternative products. In other words, looking for substitute products that give off fewer emissions than the current product when it goes to be disposed of. For example, substituting recyclable plastic cups with recyclable paper cups can present more carbon savings, since recycling paper products is typically less emissive than recycling plastic products, when considering the products whole life cycle (Source: EPA WARM model emission factors, comparing paper and plastic products).

Approximate time: 4 minutes

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System-wide thinking: opportunities

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Not all municipalities and regions collect organic materials for compost. Advocating for regional composting plans could significantly reduce methane production from landfill.
Use the college or university as a living and learning lab by setting up a pilot composting program

Advocate for organics

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Call to Action and live Q&A

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Call to Action

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Calculating your own Waste Footprint

Get started on first steps of data collection!
Note ways to improve data collection in future years.

Flexibility/Choice

Be realistic about data availability

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Thank You!

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Contact:

Annabelle Bardenheier

abardenheier@stanford.edu

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Scope 1 & 2 Solutions at Stanford

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Central Energy Facility outcomes using district-level thermal heat recovery:

Stanford’s Solar Generating Station

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Scope 3 Categories Sorted by Data Availability at Stanford

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Full Data & Reporting Available

2019-2020

Partial Data Available

Additional data needed

Exploring Feasibility/

Need Help

Not applicable

)

In the end, Stanford ended up calculating six categories!

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Scope 1 & 2 Solutions at Stanford

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SESI: Stanford Energy System Innovations

(planned)

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Sources for Researching Frameworks

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Published research (e.g. academic journals, IPCC reports)

Stanford’s existing reporting protocols (i.e. AASHE STARS and The Climate Registry)

Climate Action Plans from industry leaders and peer universities

Governmental resources (e.g. US and California Environmental Protection Agencies, United Nations)

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Importance of Scope 3 Carbon Reduction

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Purposeful university: Indirect emissions reflect Stanford’s influence and connection to regional economy, community and social good.
Efficiency driver: Strategic procurement decisions drive efficiency and savings in the long run.
Innovation driver: Supply chain innovations will connect the dots between sustainability, circular economy and sustained growth.
Institutional choices: Scope 3 is deeply integrated with environmental and social justice opportunities.
Accelerate sustainability: Knowledge and mitigation of scope 3 emissions represent a leadership (research and action) opportunity for Stanford.